John Moyle Field Day 2014 At Mt Torbreck

Hi all,

Most of my activations are lightweight, and even more so these days, using a KX1 with a random wire antenna. Once a year, I go in an entirely different direction, and that is for the John Moyle Field day contest. This is a contest with both HF and VHF and up sections. It also rewards making seperate contacts on phone, CW and digital. It has a 6 hour section that can be timed for three rounds of contacts for each station, and they can be contacted per band.

It’s the VHF and up section that interests me. Currently that interest is on three bands 6m, 2m and 70cm.

A few years ago, I identified Mt Torbreck VK3/VN-001 as a suitable site to operate for the contest, and I went there in 2012, and again in 2013. This year, I sought to improve on previous year scored. I had dispensed with the Quadruple Quads that I had used on previous expeditions and built a 6 element yagi for 2m.

Access to the summit was the usual Barnewell Plains Rd up from Eildon Jamieson Rd. It’s a little rough, but there is no real trouble getting the Prius up here. As per last year, I would need two trips up to carry the gear.

Gear included:

  • FT-897
  • FT-817
  • Laptop and power adaptor that could take 12V in
  • Signalink USB for digital modes
  • A HT for 2/70 FM
  • 8 3S 5000mAh LIPOs
  • 3 3S 2200mAh LIPOs
  • A 12 V regulator
  • Various coax pieces both LMR195 and LMR400
  • Two 7m squid poles plus the lightweight 4.7m squid pole
  • Two 1.5m al pole sections
  • Turnstyle antenna for 6m
  • Coax based colinears for 2 and 70
  • A PVC based and squid pole mounted 6 element yagi for 2m

With the removal of the Quadruple Quads, it was less gear than last year. I had also taken up less battery capacity because I used little more than 50% of it last year.

As everything was carried in by hand and was battery powered, all my contacts here were SOTA contacts.

Conditions were nice during the setup. I finished the second trip up at about 11am and proceeded to setup all the gear.

Here’s the 2m colinear:

2m colinear squid pole mounted at Mt Torbreck

2m colinear squid pole mounted at Mt Torbreck

The 70cm colinear was built the previous day before the contest, and was then tested with the MiniVNAPro and Extender. It is a little hard to get the element spacing just right – I built it a little longer than a version from last year, but it still ended up a little out of band. SWRs of mid 3s to 4 are really too high, so I’ll need to make a match for it.

Zplots view of 70cm colinear

Zplots view of 70cm colinear

The gain is still very nice, and I get away with these high SWRs because the FT-897 does not develop as much power on 70. It also cuts back the power in presence of higher SWRs. Still, I need to get the SWR below 2 to give my radio an easier time and so a match will be needed – otherwise I would have to build the thing again, even longer per segment – I’m a little over building these things now!

Physically, the lightweight 4.7m squid pole was able to take the weight of the colinear, however, given that I was also attaching some LMR400 coax, I needed to support the weight of that against a tree, otherwise the pole would start to bend so that the bottom of the colinear was not far from the ground.

Next up, the 2m yagi:

2m yagi squid pole mounted at Mt Torbreck

2m yagi squid pole mounted at Mt Torbreck

In light winds, the setup for this was fine. I am going to need to guy it for stronger winds. I can guy it just below where the yagi is mounted. The mounting is a PVC pipe t piece on the pole, with the stem of the T allowing me to put on another T piece for the beam. I am going to modify the physical construction a little more along the lines of what Peter VK3PF has done, putting the elements through the beam, rather than using a wingnut to tie them onto the top of it. This will make setup and tear down simpler.

I was pretty happy with the measured results of this antenna:

2m yagi VNAPro measurements shown in Zplots

2m yagi VNAPro measurements shown in Zplots

This gives an SWR below 1.1 at 144.18MHz. The front to back was predicted by NEC2 to be over 30dB, and it was clearly high as I moved the yagi around. Predicted free space gain was about 16dBi. I was able to use it to work VK1DA/P during the contest, although by then, winds were very high and I had trouble keeping the thing up. So improvements for next year is a guying mount and physical improvements to the element mounting. I will also put in a BNC socket just after the common mode choke. The common mode choke on this antenna is simply 6 turns of the coax around the PVC beam right next to the feed point.

Last antenna up, the 6m turnstyle from last year. It’s not the most high gain antenna out there, but it does enough to put me in the game on 6m. I’m still thinking about whether I might put in a 2 element yagi to replace it next year, however the advantage of this thing is that I don’t need to do anything to adjust it during the contest. This is handy when in the tent because it’s raining outside.

6m turnstyle at Mt Torbreck

6m turnstyle at Mt Torbreck

You may notice the dark cloud in the above photo. Unfortunately, it was a sign of things to come.

So what’s missing. I have nothing horizontal polorisation for 70cm, and my plan for that is to build a 70cm yagi for next year. I’ll take the lessons learnt from building the 2m yagi this year. I am not going to bother with any vertical polorisation antenna for 6m.

The radios were setup in the vestibule of the tent:

Radios in tent vestibule

Radios in tent vestibule

A look at the batteries – these were 3 parallel by 2 in series (effectively the cells are 6S3P) which then feeds a 12V regulator.

Mind the computer

Mind the computer

It does take a little bit of work to get the workspace clean enough in the small tent. The computer was here to provide VKCL logging during the contest and to run the PSK software (Fldigi). An alternative is to run something like DroidPSK on my phone or tablet through one of my radio interfaces.

I operated for about 4 hours in the contest. There were fewer portable stations out compared to last year, and a notable absence of picking up people participating in and around Melbourne using 2/70 FM HTs. I picked up a lot of contacts last year that way.

A number of strong showers passed through, but I heard from other contest stations further southwest that conditions were getting wild. There was sounds of distant thunder, and the radar looked bad out 100km to the west, so I pulled the plug. It felt a shame to end 2 hours early – I missed a whole available contest window. Conditions were looking not so good and there was lightning around, so I did not want to risk it.

I quickly pulled down the antennas and took the high priority gear (radios, computer, etc) down to the car first. On the way back up, a decent electrical storm came through with lightning every 3 or 4 seconds. Some strikes were within 500m. That storm passed when I got back up to the top, but now it was time to take down some of the metal gear. I actually thought about abandoning it, but banked on getting off the ridge before the next storm arrived. As it turned out, I was not quite off the ridge when the next squall came through. It was lightning every 2 or 3 seconds, the rain was driving hard and the track was a river under 30cm of flowing water. There was water absolutely everywhere. I was glad that I had taken down the electronic gear on the first trip and it was in the dry car! I still was not too happy about carrying 1.5m metal poles in the middle of an electrical storm. I felt much safer once off the ridge and about 20 minutes later the storm had passed. The rain then backed off to a more usual level. I was pretty wet for the drive home!

This was quite an experience, and hopefully the summit will be more forgiving next time and allow me to get a 6 hour activation in. I got 846 points, which I felt was not bad given the 4 hours operation, plus the lower number of portable stations. I look forward to next year with 2 yagis and a matched 70cm colinear to help extend the scores above my 2013 high.

Regards, Wayne VK3WAM

Northern Victoria 4 summits trip

Hi all,

I’ve fallen a little behind in maintaining my blog, so I will try to catch up over the next little while.

On the 19th of July, I headed up to Bendigo and gave a SOTA talk at the Bendigo Amateur Radio and Electronics Club. There was quite a lot of interest. I had previously telegraphed my intention to go out and activate a few summits the next day. A few guys from the club looked past the not so good WX forecast, although chances were it would be cold with a few showers, rather than heavy rain.

Joining me on this trip was:

  • Phil VK3BHR
  • Ray VK3YAR – who also kindly put me up on the Friday night, and
  • Col VK3LED

As it is a little while since the actual activation, I can’t remember everyone who accompanied us.

Mt Kerang VK3/VU-010

Proceedings opened with this nice little summit. The summit requires access over private land, and look at the following photo of the gate as to how to make the necessary arrangements:

Access gate to Mt Kerang

Access gate to Mt Kerang

Ray had already arranged to obtain a key, so we were able to drive to the summit. It is a walk for an hour or so if vehicle access cannot be arranged.

The summit itself is quite open. We proceeded down the north side to lose about 30m vertical and then turned around to head up, making sure we had carried all of our gear with us.

Here’s a few pics of proceedings from the summit:

Inverted V mounted on the trig point at the summit of Mt Kerang

Summit of Mt Kerang

Phil VK3BHR operating at Mt Kerang

Phil VK3BHR operating at Mt Kerang

The interesting thing about Phil’s rig is that it is a self-built, self-designed rig. Might be a bit heavy for some SOTA work, but impressive nonetheless.

Mt Korong VK3/VU-012

Next up was Mt Korong, after a quick stop at a fish and chip shop. This is on a public reserve, however there is not a maintained track to the summit. The forest is reasonably open. There are some nice views from this summit.

Looking south west from Mt Korong

Looking south west from Mt Korong

My end-fed half wave on 40m, plus the 2m colinear were in action at the summit.

Antennas at Mt Korong

Antennas at Mt Korong

The terrain is quite open lower down, so the best bet might be to park at the main car park. There is a track marked on some maps, but this is very faint and we did not follow it. Nonetheless, it is likely to be easier to head straight up from the car park, rather than trying to traverse in along the ridge from the west. This is a good mountain for those not so experienced in off track walking to get started.

Mt Tarrengower VK3/VN-023

After Mt Korong, the guys were looking for an easy one. There is a sealed road to the top. We parked down a little, and did a little trip down a valley to ensure we were low enough to be out of the activation zone on the way to the top.

Proceedings were similar to Mt Korong, with my end-fed, the 2m colinear and Phil using an inverted V on 40m.

Operating at Mt Tarrengower

Operating at Mt Tarrengower

Mt Ida VK3/VU-009

With that, I bid my Bendigo friends farewell, and headed for Melbourne, but via Mt Ida. I expected to get there well after dark and would try activating on 2m only. Access to this summit is quite easy in taking the road nearly all the way to the top. It looks to be within 25m vertical of the top, so dropping about 10m from the car park would be advised. The road in from the Northern Hwy can be a little easy to miss in the dark when coming from the south.

It was fully dark during this activation. I operated from on the corner of the fenced area using the 2m colinear. A highlight of this activation was a 2m FM contact with some enhancement with VK2KRR near Wagga Wagga.

With that, I packed up and headed back to Melbourne.

Regards, Wayne VK3WAM

Gippstech 2013 and SOTA activations

Hi all,

Last weekend I headed over to Churchill for a fix of VHF and up at Gippstech 2013. The weather was poor, so I did not bring any radio gear for activations afterwards.

Gippstech 2013

The conference was held in the usual place at Monash University, Churchill campus. It was quite interesting with topics from 50MHz to the latest adventures on 10GHz and up. The mm bands have come a long way in recent years.

Of course, on weekends there is a lot of SOTA activity. Certain persons were seen disappearing into the car park where squid poles and other items suitable for SOTA chasing seemed to be appearing:

Peter VK3PF and Rik VK3KAN discussing a lightweight 4.3m squid pole

Peter VK3PF and Rik VK3KAN discussing a squid pole

Rik VK3KAN grabbed a lightweight squid pole that is less than 50cm retracted and very light weight. This could go in all overnight packs rather than being outside. Hmmm, quite interesting.

Other people were caught out at times:

Ron VK3AFW chasing SOTA

Ron VK3AFW chasing SOTA

The weather was rainy at times, but a good time was had at conference and SOTA discussion with le tour on the TV at Peter’s. My chaser score went up over 15% just this weekend!

Mt Useful VK3/VT-016

As Gippstech wound up, I planned to head home, but after consulting the radar, the idea grew to head up to Mt Useful with Andrew VK1DA and Peter VK3PF for a bit of SOTA fun. It had been raining all morning and early afternoon, but it seemed that the WX was lifting. Peter also informed us that there was a shelter that we could activate from. This emboldened us, so into Peter’s Subaru for the trip up. The road is quite good quality, and quite passable in a 2wd pretty much all the way to the top. With the wet conditions, the road was a little soft in places, but careful driving in a 2wd would still get through. Peter had already activated this summit recently, so he dropped us off near the edge of the activation zone and then he drove to the summit. Andrew and I headed down a little just to be certain that we were out of the activation zone and then headed in (carrying all of the activation gear).

We used Peter’s squid pole and 20/40 linked dipole. One of the links had come out, so it was 40 on one side and 20 on the other. After discovering this, the signal came up and it was good signals all around.


The road into Mt Useful passes another SOTA summit. Time was late, but this summit has a good path into the Latrobe Valley. Peter called some of his club members in the Latrobe Valley, who were willing to help us out on a quick 2m activation. We hoped to get to the summit before dark, but we were also uncertain if the access road was closed due to bushfires early in the year. We left the main Mt Useful Rd about 5km north east of the summit and headed across. The road is in good condition, again quite accessible in a 2wd. It goes right into the activation zone, but not quite to the top. We drove past the activation zone and parked about 35m vertical metres down from the top.

Conditions had cleared right up. We took turns, with two of us near the car, and one climbing up about 20 vertical metres to get well into the activation zone. Peter’s mates were good signals in, plus by taking turns, each of us also chased the summit. We decided not to use 40m, due to the approaching dusk meaning the skip zone would have been building by then. Also, we did not want to stretch the WX luck too far.

With that, it was 17 activation points – including three bonus points – from 2 summits. Not bad for a quick little side trip from the conference.

Regards, 73 Wayne VK3WAM

4 Summits in the Yarra Ranges

Hi all,

With all the fast and furious SOTA action going on in recent weeks, it was time to get out and clock up a few more points, lest I eventually lose my VK SOTA activator lead, but hang on, SOTA’s not supposed to be competitive, right?

Mt Richie and Mt Donna Buang form a summit pair that are quite easy to do in a day, and that’s what I did last year. This year the plan was to add two extra summits onto the day, Mt Bride and Britannia Ridge. I had not activated those last two before, but plenty of others have.

Mt Richie VK3/VC-003

This summit is accessible by a series of management vehicular tracks. There is a gate for Road 15 at Acheron Way. The large bolted concrete barrier is to stop the public driving up, but foot access is ok. The track log below shows the route.

GPS tracklog plot of Mt Richie access

Mt RIchie tracklog

The junction between road 10 and 15 is at the most southerly point on the tracklog. Turn left, and it’s about 5km walking from this point. The route involves over 500m of climbing, but it never feels too bad on the way.

I first put up the vertical, but I need to do a bit of soldering on the feedpoint as the connection was poor. The base of the loading coil seemed disconnected, I am going to have to look into this. No action on 12m with a poorly functioning antenna.

Lucky the end fed was in the bag. I took down the vertical and put up the end fed and worked a series of VK1,2 and 5 stations. Good reports. It would seem at this stage in winter in the hour or so after sunrise, sometimes there can be a large skip zone on 40m. Bernard VK3AMB reported hearing me very weakly, must have been ground wave over a 45km distance. I did not bring the 2m colinear for this summit.

My phone struggles to take photos in cold conditions, so no activation photos from here.

Mt Donna Buang VK3/VC-002

It’s next off to Mt Donna Buang with the walk back to the car and then the drive up to the summit. The last car park before the gate is 40m vertical down from the summit, so I parked here. Looks a little strange with other members of the public parking at the summit itself, but it ensures my final access is non motorised. I set up near the lookout tower with the 2m colinear and the end fed both on the squid pole at the same time.

2m colinear and half wave end fed on the 7m squid pole at Mt Donna Buang near the lookout tower

Operating at Mt Donna Buang

The only implication of this set up with a 2m coax run from the feedpoint to the radio is the need to move about 5m when I want to move from 2m to 40m. Aside from that, it worked well. I used the Wouxun HT on 2m FM, and the FT-817 on 2m SSB and 40m.

Mt Bride VK3/VC-009

Mt Bride was my third summit of the day. With things running nicely to schedule, I decided to activate both on 2m and 40m at this summit. I used Mt Bride Rd off Old Warburton Rd. A road branches off to the left just under 2km from the summit. It’s a bit rough, but I got the Prius up without any real difficulty. I parked the car at the crest of this road and found the walking track branching off a little further along.

GPX tracklog screenshot of Mt Bride access

Tracklog to access Mt Bride

Someone had recently rode a dirt bike up here. Might have been “fun” with some of the low hanging branches!

I activated on the track as it was well in the activation zone, perhaps less than 5 vertical metres from the highest point.

Activating using a squid pole on the track near Mt Bride summit

Activating at Mt Bride

I again mounted both the colinear and the end fed on the squid pole. It’s working well. I was unable to get the full four contacts on 2m, but there was the usual pile on 40.

Britannia Ridge VK3/VC-011

Conditions up to this point had been quite sunny, but the clouds started rolling in. It was time to get this last activation in place. I accessed it by continuing to drive along Mt Bride Track until reaching the base of a track that goes up a spur towards the summit. Mt Bride Track is fine in a 2wd. The track going up the summit would need a much more capable vehicle. It’s about 200m down and 1300m away from the summit, so it is not a long walk.

GPX tracklog screenshot of Britannia Ridge access

Tracklog to Britannia Ridge

I headed up to where the track levelled off before going off track up to the summit. I did not look too closely at the map, but the track perhaps does not quite get in the activation zone. My way back down to the track was quite more open. Look to leave the track about 50m before it levels out at the top.

My operating site was quite cramped, and for this reason I did not put up the colinear and the end fed at the same time. I commenced operating on 2m. I did some coordination on VK3REC as I had no mobile signal. I worked 2 stations on 2m FM, and Bernard VK3AMB put out a call to see if anyone else was around and perhaps SSB might be a go. I tried getting Marshall VK3MRG, but I could just hear him and there would be little chance he could hear me on 5 watts. Just after pulling down the colinear, another station announced on the repeater that they had my signal booming into them, but they could hear nothing on the 2m 1/4 wave. Bernard himself could hear nothing on the 1/4 wave, but 57 on the colinear. It certainly makes a difference.

I put up the end fed and worked the usual pile on 40. Interesting that 40 was still open locally late in the day after being closed even an hour after sunrise on Mt Richie.

With that, packed up and got back to the car just a little after sunrise. A nice productive 30 point day, and the uniques count was expanded by 2.

73, Regards, Wayne VK3WAM
South west of the summit

SOTA activations in and around Bunyip State Park

Hi all,

This last Saturday it was time to head for the hills again. After last week’s trip, I was keen to get summits in on this trip that I had not activated before. There did not appear to be fire reduction burns in this area as well.

The plan was to activate the first, Spion Kojpe, on 2m and then the rest on 40m + other HF. I packed the end-fed for the 2nd and 3rd activations, and I planned to use my vertical on a squid pole for the 4th and 5th activations.

Spion Kojpe VK3/VT-040

It looks like the easiest approach to this summit is via Limberlost Rd, leaving the Noojee Rd at 016066 (remember this is the 10km, 1km 100m of the easting and then the same for the northing UTM or Map Grid of Australia). The road is quite good for 2wd, although some of the lower sections were a little soft due to recent logging activity. Higher up, the road was quite firm. I headed up to the junction of Limberlost Rd and Outlook Track at 986030. The track leaves here to the south west, easily seen from the road junction.

Time to get the gear ready. Squid pole, and 2m colinear, check. Put aside the HF antennas, grab the HT, FT-817 mike, CW key, batteries, power cable, all check. Good to go, but what about the FT-817 itself? Ahhh, not here. What am I going to do. I did want to do this summit on 2m, but all the others were for HF – well, it’s too far to drive back home. 2m FM it’s going to have to be and here’s hoping the 1700mAh battery in the Wouxun KG-UVD1P can last.

From just a few metres to the west of the road junction, the track heads off south west. It’s quite good for the first 200m, but then degrades. It can still be followed however, and it is best to stay on it. Look for the blue flagging tape, and if you lose it, simply retrace. It makes it’s way to a large flat rocky top where I put the squid pole up on a nearby tree.

Things worked quite well here, and I quickly got my required contacts on FM. I put the radio down to 1 watt to conserve the battery as things rolled along.

I went to take some pics in the quite misty conditions. The summit was in the clouds. The screen went black and the phone switched off. I turned it back on and it complained about low battery. Hmmm.


This was my first go at using this Android GPS app. It uses Oziexplorer maps, which for south east Australia can be obtained here. It also can load in a few internet based maps, of which the one I find most useful is the OpenCycleMap, which is a derivative of OpenStreetMap. Of course the internet maps need an internet connection to update. Phone coverage was patchy up here.

The app is fairly easy to use, and the navigation feature is nice. One thing though is that this app is heavy on the battery. Before my little hickup with the phone camera, my phone had gone from 100% at the car down to about 70% in one hour. That’s pretty heavy. It also crashed a few times and needed restarting. So there is a few bugs, but the heavy power consumption is something that is going to have to be looked at.

Gentle Annie VK3/VT-078

Next summit was Gentle Annie. I am driving a Prius up here, so I’ll avoid the 4wd tracks. I drove west along the main rd, which goes through a few names until I arrived at Bunyip Rd at 899037. Turning left, it was straight forward through Bunyip Gap and through to 958991. Gentle Annie track heads off from here. I would not like to get a low clearance vehicle up here, and it would be too steep for the Prius. I had planned to walk, and no FT-817, it was the 2m colinear heading up.

I got to the top and set up at the trig point. The trig structure looks like someone has crashed into it at some stage and it’s leaning over a little. Still ok for clamp the squid pole on. Setup the colinear and started calling. No responses. After about 10 minutes and the UTC change-over I was wondering what was going on. Of course the Wouxun has no SWR meter to tell me if all is not well. I tried with the 1/4 wave and got some responses. After a little detective work, using reports from chasers, I identified that the match for the colinear was playing up. I jury-rig fixed it, and the reports were much better. It was interesting that the reports were little different from matched (about SWR 1.15) vs unmatched (about SWR 2.3). The Wouxun is clearly not reducing power into a 2.3 SWR. Not ideal, but not too bad. It was also likely not reducing power into that shorted match setup that I had going at the start of the activation. Lucky the HT still works!

I tried to take a photo of the setup at Gentle Annie. The phone camera app came up after an unusual delay (and a black screen for about 3 seconds). I took the photo and the phone switched off. I turned it back on, again to a low battery warning and no actual photo had been taken. Well that’s it for photo shoots for today.

With this activation, I had now activated 100 unique summits. It was something that I had targeted quite early in getting into SOTA, and it was my main objective for this trip.

Back down to the car, and I was going to have to try and get what charging I could into the phone while driving around.

North Hell’s Gate VK3/VT-050

With the phone battery low and the heavy battery use from Androzic and the dodgy camera, I would need to fall back to the old favourite, Trekbuddy with loaded Forest Explorer maps taken from screenshot grabs. Trekbuddy is reasonably light on the battery, and I have all the VK3 SOTA summits loaded in for that app as well. One side benefit of this is that with Trekbuddy having the GPS on and fixed, I could run Androzic for a quick look at an Oziexplorer map with a GPS fix already there. Look at it in that app, and then exit.

I had heard a few stories about this summit being somewhat hellish to access. I used Proposch Rd to access it. The road heads up to a point about 1.1km north west of the summit. It forks in two. One road quickly ends to the north east of there. The other goes over the top and heads south towards recent logging activity. I went up this and packed at the ridge top. There was an old track that I then used heading east from here. Distance to summit about 1km. This heads near point 584 at grid ref 992980. It continues east-nor-east down a shallow saddle and up again. I followed my nose a bit, and some tracks headed off and ended. I would head back and try to stay on the ridge. I was at about 220m bearing 140 from the top where I left the faint track I was on. I was to find out, I should have stayed on it a bit longer, I reckon it gets about 100m from the summit bearing 150 degrees (or from the summit head 330 degrees).

So as it stood I had about 220m of bush bash. There was some long grass and vine plants around that made it tough going. None the less, I got to the top and found a track goes to the top. Talking to others who had been here, this track goes nowhere, so I did not try to find out where it went.

I again activated on the 2m colinear. After finishing up, I headed north east. This was a bad move as the country drops away quickly and the vines and grass are far worse here. It was real tough going. Given Glenn VK3YY had lost his squid pole around this place, I was very concerned about losing mine. I had got about 200m with a bearing of 190 degrees to the summit, where I realised that I had gone too far east and needed to head west-nor-west and gain some height again to get back on the track. The forest did ease up, but I spend about 1 hour of needless bush bashing (all for an extra 200m!). At least it helps make you fit. I found my old track about 30m closer to the summit from where I left it on the way in, and noticed that it made its way from around here up almost straight for the summit. Being at the summit before, I know it does not go the whole way, but I suggest that future access should go along this track, go to the end, take a waypoint, and there could be less than 100m bush bash to the summit. Use the waypoint on the return trip.

South Hells Gate VK3/VT-059

So back to the car (much faster when on the tracks), and I attempted to find my way to South Hells Gate. First try was the logging road at the end of Proposch Rd. It heads underneath North Hells Gate, about 1km from that summit (west and then south west). Most of this side has been recently logged, and access across it would be quite fast, but I headed back to Forest Rd and made my way down that. There’s a track near Ryson Creek which I tried, but the start was too steep for the Prius. I then headed down to Bullock Link Track. It also looked steep, so it was time to park the car and walk it. About 4.5km and about 440 vertical metres to climb. It took about 55 minutes to walk this. This 4wd track would only be considered double diamond. It was hard to walk in some places, and somehow people are able to get 4wd cars up here!? I know they can ’cause I met a few using the track on my walk.

The summit itself has an activation zone about 500m long. I activated a little to the south-west of the marked summit, about 5m down from the top. Again, of course on 2m FM, but it looked like the HT battery was going to last the day, so I was now at 5 watts.

Dingo Ridge VK3/VC-028

The final summit of the day was a little 1 pointer kinda on the way home. 1 point, but also 1 unique for me, as I had not activated this before. When it comes to uniques, 1 pointers are worth as much as 10 pointers. After conferring with Peter VK3ZPF, I decided not to approach this summit from the south, but instead to approach from the west-nor-west using Lupton Track. This would be about a 5km walk. It took me about 55 minutes to do the walk in. I headed off with about 15 minutes before sunset, so it was pretty dark when I arrived. I needed to stop about 200m before I hit the junction with Dingo Ridge Track to get the headlamp on to read a sign. I activated at the track junction.

The first three contacts were quite quick, but then it was into a long period of calling with no responses. Bernard VK3FABA found someone else for me to work VK3UFO. I could here him fine, but he could barely hear me on FM. No SSB here. We had to be innovative to get the call-signs and reports exchanged, but it was done directly, with Bernard relaying any other information aside from these to make it easier. Calling Victor Victor Victor Victor, Kilo Kilo Kilo Kilo, 3 3 3 3, Whisky Whisky Whisky Whisky, Alpha Alpha Alpha Alpha, Mike Mike Mike Mike did seem to work. My received report was 2 and 1.

With that, and conditions totally dark now and windy, it was time to head for home. 5 summits all new uniques for me, and 11 points for a full SOTA day out.

Sorry no pics, but I did test the phone camera back at home and it worked fine. Hope it does not play up again on the next misty day out.

Regards, 73, Wayne VK3WAM

4 summits activation

Hi all,

Another weekend, another time to get out and have a look at some SOTA summits.

The plan

The plan for this trip was to activate four summits that I had not activated before, VK3/VN-006, 007, 008 and 010. VK3/VN-006 Keppel Ridge is a summit in the shadow of Lake Mountain. The other three are fairly close together a bit further to the east. I started off heading down the Eildon Warbuton Rd, which starts off quite wide, and made my way along to a road to go across to Mt Duffy VK3/VN-007. I found out that Gum Top Rd was closed due to a planned prescribed burn, along with Rough Hill Rd. Even Reefton Logging Rd was closed, so I could not access Mt Duffy, with the two other SOTA summits behind it. Well, I’m out here, I might as well activate something.

Keppel Ridge VK3/VN-006

This was my last planned summit of the day, but it ended up being the first. I headed up Sandstone Rd up to point (ed) 057485. This is a little down from saddle which has a lot of logging regrowth. We would like to avoid that horrible stuff. The forest a little lower down is quite open and gives reasonable access to the summit. Up on top, I ended up activating only a little late from my planned activation of VN-010, and there was plenty of chasers waiting on 40m.

Federation Ridge VK3/VN-003

Next up, to make for a complete day, I wanted to still get 4 summits in. I headed for Lake Mountain, after checking that I had not activated this summit this year. With many summits in VK3, I would rather get fresh activator points for each activation than not. As this summit can be worked on 2m I decided to go for that. Also, last time I was here, I could not use the 2m colinear. I was eager to have a look at the difference. Last time, I could only work Peter VK3PF on SSB, and signals were 51 both ways, good readability, but weak on a 1/4 wave. This time it was 58 and 53, so much better. All the other stations worked were different from last time. It was lightly raining, so I aimed to keep the activation short to not get too wet and to keep the chance of getting four summits in.

Sugerloaf Peak VK3/VN-011

Next up, a good sporting summit with a bit of a rock scramble. It had not rained here yet, so the rocks were dry on the way up. I was tempted to join the dog piles on 40m, but again this was a summit where V1 of the colinear had failed. I was keen to try it here again. This time it failed again! I checked things out and found it was my FM series match stub. I had to use the colinear unmatched, but VK3FABA reported me 58 on the 1/4 wave reported me 60 over on the colinear. Perhaps not really 60 over, but it’s more about 25dB to 30dB up.

Unmatched, the colinear has an SWR of around 2.5, which is not great but it still puts me in business. I’ll need a soldering iron to repair the stub.

I could here Peter VK3PF call on SSB, but he could only dimly hear the CW I sent back. I think a matched colinear could get to Churchill from here, on 5W QRP.

Mt St Leonard VK3/VC-006

Final activation of the day is an old favourite. I went for a quick activation, huddled underneath the public lookout platform for a little bit of shelter. The metal around improved the unmatched colinear to an SWR of around 1.7

It was nice to be able to work Peter VK3PF from here 2m into Churchill. Everyone else was LOS, so plenty of 59 signal reports.

In all, I missed out on the 4 new uniques, instead only adding one. Walked away with 26 SOTA activation points rather than 24. I think my priority order for SOTA is:
1/ New activation uniques
2/ Activation points
3/ S2S points
4/ Chaser points (nice to get if they are there)

Also, I like a challenge, and 2m provides more of that challenge (so long as it is a realistic challenge). 40m has plenty of pileups these days to keep SOTA quite active there, but where 2m is possible, I’ll think I’ll focus on that.

Maybe, I should try 40m CW only as a bit of a challenge and join VK3BYD!

One final note: The internal batteries on my FT-817 are not giving as much operating time as they used to. I reckon its down to about 50% of new. They have had a fair amount of use, but this is not really a fantastic service life. Looks like I’ll be going to an alternative soon. I think I will give the HobbyKing NiMH AA cells a good spin as they look good, otherwise a LiPO will be going in there.

73 Wayne VK3WAM

VK1 wilderness trip

Hi all,

I went out on an extended 4 day walk this last weekend. The aim of the trip was to visit a series of remote wilderness areas in the Bimberi Wilderness. This area contains many high value summits in the VK1 / ACT area for Summits on the Air, and my plans were to activate 10 of these summits.

Mt Ginini VK1/AC-008

Mt Ginini is located about halfway down the western side of the ACT border with New South Wales. There is a road coming in from Canberra, and another through the Brindabellas from Tumut. Coming from Melbourne, the Tumut access route was the one I chose, and the road is sealed, except for about 30km. It is a good high standard gravel for the rest. Some of these sections are steep, but some seal has been put down for the worst parts. Due to this, even in poor weather, this road could still be passable in a 2WD. Mt Franklin Rd can be accessed from these roads, and this goes through several gates (locked in winter) through to the summit. One can drive right to the top, so I turned around and drove down about 50 vertical metres to ensure I was well out of the SOTA activation zone.

I put up the 2m colinear, which was attached to the fence of the Air Services Australia site. The metal did seem to affect the feedpoint impedance of the antenna a little, but it still worked quite well. I put out a call on a repeater that services the VK1 area, VK1RGI. This repeater itself is located at Mt Ginini. A number of stations came back, most of which would become like old friends over the coming days.

Here’s a look at the peak in the late dusk light:

Late dusk light at Mt Ginini summit

Mt Ginini

With that, and a few big days ahead, I drove down to the track head near the summit for access further south. I camped there the night for a early 6:45am departure the following morning.

Mt Gingera VK1/AC-002

This summit is the most accessible 10 point summit in VK1. Access is via a continuation of Mt Franklin Rd as a MVO track. It’s about 5km to the start of a walking track that heads up to the summit. I dropped my phone on the track, and that was my camera – so no photos. I did recover it on the way back down – so at least there are more photos to come. I did at least get a picture of Pryor’s Hut.

The summit has a few small boulders plus some low snow gums, so it was reasonably sheltered from the wind. There are good views to the south west from here, with Mt Jagungal clearly visible. I remember doing an activation of that mountain a few years ago, but those were pre-SOTA days. It awaits my return when SOTA comes to VK2.

Again, the 2m colinear worked well here, and the VK1 chasers came up quick after a call was put out on VK1RGI. The feedpoint impedance of the 2m colinear was back to normal, with the FT-817 showing zero SWR bars most of the time.

Mt Ginger Ale VK1/AC-007

This summit is also accessible from what is now the Mt Franklin fire trail. Apparently this track is to be upgraded for fire management purposes, but I do not imagine that it will be opened to vehicles.

There is no track to the actual summit. I walked to a point about 700m south of Blackfellow’s gap, where the track stopped climbing and dropped my pack there. The top of my pack can be used as a small day pack, so I had my radio gear in there for the climb up to the summit, using the squid pole as a walking pole. It’s not as good as a real walking pole as a walking pole.

It’s about 260m vertical climbing through light scrub to the summit. There’s a few false tops along the way. Here’s a pic taken near the summit:

North east from Ginger Ale

North east from Ginger Ale

I worked Andrew, VK1NAM from VK1/AC-021 on the way up, just before UTC midnight, and then again summit to summit from the top. Again, the colinear worked a treat as it would until near the very end (it still worked, it just was a little sore from the beating it was to take)

I could hear VK3AFW calling for me on VHF CW, but he could not hear me. It was still a highlight to hear such a DX signal coming in.

Bimberi Peak VK1/AC-001

Next up was the ACT’s highest summit. First on the agenda was to draw water, which I did so at the junction of Laura Gap Trail and Mt Franklin Fire Trail. The next item, how to access the summit. Options were: 1) to take Leura Gap Trail up to the gap from the junction of Mt Franklin Fire Trail, 2) to go straight up from the junction, or 3) go about 1km to the east on Leura Gap Trail and take the next spur up. I went for option 2. I still am not sure about how options 1 or 3 would go. It was thick going with different types of scrub transitioning at 1400m and then some real rocky progress at around 1700m. This really slowed me up. Above 1700m, it’s clear. By that stage, I was quite tired and was experiencing cramping. I had to take it slow and easy up to the summit, set up the tent and then activate the summit, again using the colinear on 2m.

Here’s looking north from about 1750m altitude:

Looking north from Bimberi Peak

Looking north from Bimberi Peak

I did finally make the summit itself:

Camping and operating from Bimberi Peak summit

Camping and operating from Bimberi Peak summit

And here’s the view in the very late light.

Looking north from Bimberi Peak summit at late dusk

Looking north from Bimberi Peak summit

Mt Murray VK1/AC-003

And so the tour continues. I aimed to leave on first light and headed down, first a little to the west of the spur, but I made my way back on. The trick would be to leave south east, not south from the summit. It was good progress with light to medium forest down to Murray Gap. Much easier going than the previous day. Down there, I met some campers who were planning on ascending Bimberi Peak. Parks management had recently put a new sign in to mark Murray Gap, and hid the old one in a few trees:

Old sign for Murray Gap

Old sign for Murray Gap

I then headed straight up towards the summit of Mt Murray from there. It was steep, but the forest was open, so it was good progress right to the top. Here’s a view from the summit:

North east from Mt Murray

North east from Mt Murray

I then headed south east to a marked stream to get some water and then headed towards Yaouk Gap. The scrub started getting bad at around grid ref 632463, and it was just short of 2km of scrubby stuff which took about 2 hours to get to Yaouk Gap. Not looking good for Mt Scabby tonight.

Mt Scabby VK1/AC-005

From Yaouk Gap, this could be accessed by traversing along the ACT/NSW border which goes along Scabby Range, or heading south into NSW on Kennedy’s Rd – although I am not sure if some of this is on private land. Maurice Luton Trail proceeds parallel to Scabby Range and gets within 2k of the summit (but all the climbing still needs to be done). The climbing part is a moderate to heavy scrub bash all the way up. Going along Scabby Range is worse, some parts in there were not good at all, with progress down to 500m/hour. With so much time lost, I had to give up on activating Mt Scabby on the Saturday, instead aiming to make camp near water and activate the summit first thing the following morning. I ended up getting into the head waters of the Cotter River, just below the summit at 8:30pm and made camp there, well after dark.

The next morning, it was just a short walk up from camp to the SOTA summit.

Here’s a look at where I camped:

Camping underneath Mt Scabby

Camping underneath Mt Scabby

There was a VHF DX net on 144.2 that morning. I could hear many VK3 stations, but I could not work any of them. There were a few distant VK2’ers that went in the log, aside from the usual. I could not hear VK3HRA, but VK1NAM worked him on aircraft enhancement that morning.

Mt Kelly VK1/AC-004

Onward we go to Mt Kelly. Progress here was faster than yesterday, with odd scrubby sections, but mostly open. Here’s looking north from the Mt Scabby area towards Mt Kelly:

Mt Kelly from near Mt Scabby

Mt Kelly from near Mt Scabby

There is a lake marked at 688430, but it was dry. I had planned to camp here, lucky I didn’t. There was some water about 500m to the south, and likely water 500m to the north west.

From there it was moderate going up to Mt Kelly. Progress seemed to be faster on the western side of the ridge. There were some nice views from the summit:

South east from Mt Kelly

South east from Mt Kelly

After the activation, again using the 2m colinear, I headed down the eastern slopes of Mt Kelly. The scrub was thick in places, but it is easier going down than up. There was a large open area between Mt Kelly and Mt Namadgi called Rotton Swamp. It was not really a swamp, and the water I got from there was quite nice.

Mt Namadgi VK1/AC-006

From Rotton Swamp, it was time to head up Mt Namadgi. There seemed no obvious good way up, and the scrub was simply shocking in places, with progress down to a metre a minute at times. After about 2 hours of scratches, bashing and feeling exhausted, I found a large rock face to start heading up. The last 100m vertical was very steep, but progress was much faster than the scrub lower down. With significant time lost, I decided not to get out the colinear for this activation, instead activating simply using the handheld with it’s 1/4 wave antenna on FM only. This was more than enough.

I got this nice view of Mt Burbridge and “Rotton Swamp” on the higher slopes of Mt Namadgi:

Mt Burbidge and Rotton Swamp from Mt Namadgi

Mt Burbidge and Rotton Swamp from Mt Namadgi

Mt Scabby can be seen in the above pic, in the centre but in the distance.

Here’s the view looking north from Mt Namadgi:

North from Mt Namadgi

North from Mt Namadgi

Before dropping off the summit plateau, I found this interesting Aboriginal site, which you can read the sign for yourself:

Aboriginal initiation site on Mt Namadgi

Aboriginal initiation site on Mt Namadgi

Interpretive sign at Aboriginal initiation site

Interpretive sign at Aboriginal initiation site

With that, it was a drop down into the next valley to camp for the night. It was tough going to get started, but then the forest moderated. It was not open forest, but certainly less bad than what had been experienced earlier. It was good to have a little rag chew with Matt VK1MA on the VK1RGI repeater from inside the tent after another long hard day.

Mt Mavis VK1/AC-011

Next morning, up to leave at first light and to climb Mt Mavis. The first part of the climb was semi-open forest, but it didn’t last. The top of the mountain was not open, with heavy thick scrub, with lots of dead wood to make it harder. I ended up activating on a large bolder.

Activating at Mt Mavis

Activating at Mt Mavis

The colinear showed some signs of wear and tear at this activation, with a short developing. I was able to massage it to keep it working. The fix will be straight forward, by further reinforcing the joins on the 1/4 wave aluminium pole that joins at the feedpoint. It is this section, rather than all the soldered inner conductor to shield solder joins, which takes much of the physical stress, both in deploying the device, and during the large amount of scrub bashing that had been going on. I also secured the coax using some tape against the other end of the 1/4 wave pole to reduce the stress on this connection, and that had failed. I’ll just use more tape to make it physically secure, but still, this thing had preformed well – it still did this activation here – and it had taken an incredible amount of physical punishment.

A note about the squid pole. I had long lost the rubber stop at the end, but had replaced this with a rubber foot for chairs that Bunnings sells. That works much better for scrub bashing. I also put the squid pole in a 1m 50mm PVC pipe to protect it, and given all the scratches on this pipe, it is doing it’s job! I have reinforced the top and bottom of the largest squid pole section with tape. Even with all the scrub punishment, the squid pole shows no sign of harm.

After the activation finished, it was time to get out. I had hoped to work Micheal VK1XYZ from Bimbiri Peak s2s, but it was not to be.

Here’s a last look at the top:

Summit area of Mt Mavis

Summit area of Mt Mavis

Getting out meant dropping down from the summit, aiming for grid ref 744501 in the valley. I ended up working Michael from Bimberi Peak after 45 min of descending. I was very surprised about this because I was on the wrong side of Mt Mavis from him. It was a weak but readable signal. I also expected to lose the VK1RGI repeater, but did not lose it at any time. It was weakest at Murray Gap (with Bimberi Peak in the way), but still 1 watt from the HT from there could easily open it, I’m sure 5 watts would be readable.

It took nearly three hours to get down, with heavy scrub nearly the whole way over a 600m drop. The valley was easy going, with good water in the river. The track also goes up the valley further than marked on my map. I picked it up at around 750496. It crosses the (then small) river twice, but ends up on the western side of the valley heading downstream. Here’s a look at the lower valley:

Large open valley

Heading home down the valley

From there it was not long before Andrew VK1NAM and myself caught sight of each other. He had come to pick me up and ferry me back to the car. It was a change of plan from the original, but neither AC-006 or AC-011 would have been possible without it.

It was quite a big trip, with some days having nearly 12 hours of walking, but the summits are in the log, the views in the memory and taken with the camera, and that’s what counts.

Regards, 73 Wayne VK3WAM

Postscript: Equipment review

I took up three 2.2Ah LiPOs and used just short of two of them. One activation was done on the internal battery, which was used up about 50%. The Mt Ginini activation was done using a 18650 Lithum Ion pack, which I generally use on QRP activations, but that was not far from the car. I did that to keep the three LiPOs fresh for the pack carry part. The radio was a FT-817, generally operated at 5W.

I used a Wouxun HT for my comms to the VK1RGI repeater. By the end of the trip, I had gone through two 1400mAh packs, and had started on a 1700mAh pack. Most of the time I had this on 1 watt for the repeater, and 146.5 FM simplex at 5 watts. I really only used it on Mt Namadgi for actual activations, plus a few ones to chase others while I was transiting between peaks.

Sorry to the VK3 guys who might wanted to have got these summits. I would not carry a yagi for horizontal polorisation into this country. I did have the end-fed for 40m, but time did not permit putting it up.

Matching the 2m Colinear for FM

Hi all,

I have described my efforts in building a colinear for 2m over several posts. The base unmatched colinear was sort-of ok at 146.5, but not very good at 144.1, soI set about performing a match for 144.1 using data obtained using BlueVNA and the mrs MiniVNAPRO vector network analyser. This has resulted in a fairly good match, with an SWR around 1.7 and the FT-817 showing only one SWR bar. I can live with that.

Considering a match for FM

Back at 146.5, the FT-817 shows 3 bars. This is not so good – its not a disaster match, but it is not too special either. My earlier analysis suggested that I could put a stub out a few cm further from the feedpoint, but this did not work. I think the reason was that the data I was getting from the MiniVNAPRO was not that good. Recently, I sought to rectify that, as discussed in this post, which the discussion relates not only to the extender but the base MiniVNAPRO as well.

With that in mind, I set up the 2m colinear and did some tests. Here is a screenshot of Zplots showing the data I obtained:

Zplots showing resistance and reactance of the 2m colinear at the BNC connector

Impedance at the BNC connector

Just for piece of mind, I ran the analysis with the extender, and this is what it shows:

Impedance at BNC connector obtained using extender, which shows very similar results

Impedance at BNC connector obtained using extender

The results are quite close, and any analysis done with one data set will pretty much be matched from the other.

The T piece for the 144.1 match

As well as the BNC connector for the radio (or a cable going there), I also have another convenient point to consider matching – the same place I have the stub for 144.1 I have put a BNC t piece here to connect the stub (and disconnect it when I don’t want it). I know I can’t use another stub for 146.5 right at this point on the transmission line, but I could use some surface mount components for a shunt, or add an extra piece of coax and put a shunt off that. We’ll first look at the data from this point:

Impedance at the T piece

Impedance at the T piece

The interesting thing about this is that this is an effective transmission line transformation. If I use zplots to consider the effect of 36cm of RG58 on the impedance, I get the very similar results, and there is about 34cm of RG58, plus the BNC connectors in the middle. The results are not exactly the same – the empirical results are a little flatter because of loss in the cable.

The impedance looks quite different, but if you consider the plot on the smith chart over on the right, it is simply rotated nearly halfway around the centre of the chart. This is the effect of a 50 ohm coax transmission line.

Now I can’t use a stub right here, but lets see what linsmith suggests I can do:

Match design in linsmitch showing the untransformed impedance then two steps of transformation

Match design in linsmitch

First up is to use 15cm of RG58 to get to a point where a series stub could match. The untransformed impedance is the pink dots – this is taken from the Zplots data. If you look carefully at the smith chart from “Impedance at the T piece”, you’ll notice a subset of that curve is shown here. The 15cm of coax transforms this to the green dots. Putting the series stub with a short 18cm away then transforms it to the red dots.

Series stubs are more difficult to create than parallel stubs. The inner conductor of the coax must be broken, but the outer conductor allowed to continue. The stub inner conductor must be connected (eg via solder) to one side of the line inner conductor and the shield to the other. This is logistically quite difficult.

I also provided about 5cm of extra coax with another BNC connector on the other end. This will allow me to easily put this segment into the colinear when I want to match to 146.5, or to take it out. When I am operating on 144.1, I do not want this segment with this stub.

Here is the data with the match in place:

2m Colinear matched in the FM band segment

2m Colinear matched in the FM band segment

I didn’t quite get the match quite right, the best match is around 147.3, however I can live with this. A FT-817 shows no SWR from 146.2 all through to 148.

Now why did it not quite match? I think it’s because I might have stubbed about 10mm too short. Such is life. Here’s a linsmith look at this assumption:

linsmith analysis of the match result

linsmith analysis of the match result

Note: I’ve added an extra bit of transmission line to account for the measuring point of the VNA – it’s not right at the stub point. This means the red dots are replaced with a second lot of green dots, with the new red dots after the extra coax transformation – note that these calculated red dots fairly match the empirical data shown in the zplots smitch chart in “2m Colinear matched in the FM band segment” above.

This analysis shows that I might actually be able to take off about 5mm from the stub and I’ll further improve the match. I’ll not do that straight way – I’ve got a big trip to the Australian Capital Territory coming up and the match is already fairly good – good enough that further improvement might have only marginal effect.

Anyway it’s pleasing to have a good match now at 146.5, and I’ll be using this a lot in the next week.

73, best regards, Wayne VK3WAM

4 summit activation around Mt Dom Dom

Hi all,

Again, it’s time to head for the hills and get into some of that SOTA good oil. For this series of activations, I wanted to have a good look at 2m again, and the colinear was planned to see a lot of action. I did take the end fed for 40m, but the plan was to only use it if I could not get 4 contacts on each summit. We’ll see how things go.

Mt Vinegar VK3/VC-005

This summit is between Dom Dom saddle and Mt Donna Buang. From either place, it would take some time to get in, and this was my original plan. On looking at maps, I thought I might be able to get closer access from Acheron Way, and this proved to be the case.

Access can be via Caters Gap Rd and this is a forest road with large aggregate. Forest Explorer shows it becoming a 4wd track, but the road quality remains good. I thought I would use the Cleft Rock Walking Track, but could not find it. That area had been subject to recent logging, so the track would have been destroyed anyway. I proceeded to point 825356 and turned left, to head up the hill. This went through a logging area, but the track remained passable for a 2wd without too much difficulty. I climbed up the mountain and parked about 843345. I could have gone about another 500m before a locked gate about 1km from the summit. In any case, it was a much shorter walk than I had anticipated.

I put up the colinear and called on 146.5 FM. This was going to be the most difficult summit out of the three that I had planned for the day as Mt Vinegar is hidden from Melbourne by a few closer hills that are part of the Donna Buang system. Even on VK3REC, a EMDRC repeater, action was slow – but this was not because I could not reach it. Perhaps people were slow out of bed today. I was able to reach the repeater with just a HT with a 1/4 wave antenna, so I was able to keep the FT-817 on the colinear. I eventually had to try 144.1 SSB to get the 4th contact. The stub I have for the antenna gives a good SWR at 144.1, so it is good to see that this project has obtained a good result.

Here’s the operating location at Mt Vinegar:

Operating location at Mt Vinegar showing a squid pole. 2m colinear, a backpack, a FT-817 and other radio gear

Operating location at Mt Vinegar

When operating, it’s always nice to have a good rock to sit on:

The shack at Mt Vinegar showing a rock to sit on, plus the pack, a Wouxun HT, a Yeasu FT-817 and other gear

The shack at Mt Vinegar

With the car closer than planned, I thought I might be able to get to Mt Gordon a little before 11am for the UTC midnight change over.

Mt Gordon VK3/VN-027

This summit is part of the 2013 batch to join the SOTA program in Victoria. It is a summit located between Marysville and Narbethong. Access is via a 2wd track that heads off to the north from Marysville Rd which is shown in Forest Explorer as a 4wd track.

There is some commercial gear at the summit as shown below:

Commercial towers at Mt Gordon

Commercial towers at Mt Gordon

With these commercial towers, I imagined that I would suffer from QRM problems with overloaded frontends and it proved to be the case. The colinear is fantastic at bringing in weak signals, but the downside is an overloaded FT-817 front end. With the FT-817 overloaded, there was no point trying the Wouxun HT.

I was able to get two contacts before 11am, and a good number afterwards. I had enough FM contacts to get the SOTA activation points, but sometimes it took some patience. I was getting into Melbourne well enough, but the QRM would take out the readability of other stations. It came and went, and when it was absent, I had a sub s1 noise floor.

A nice touch at the end was getting VK3PF on SSB at 146.475 This frequency is turning out to be a SOTA vertical SSB frequency of choice, just a little down from the national FM calling frequency. I still go down to 144.1 for the SSB chasers down there still, although most of those have horizontal antennas at that frequency, so there’s a bit of a mismatch with my vertical colinear.

Here’s a look through some of the regrowth (and cooked dead trees) towards Marysville from the summit:

Marysville from Mt Gordon, with some dead trees in the foreground. The slopes of Lake Mountain can be seen in the background

Marysville from Mt Gordon

Here was a good view of the Cathedral Ranges from Mt Gordon:

Cathedral Ranges from Mt Gordon

Cathedral Ranges from Mt Gordon

Mt Dom Dom VK3/VN-017

Call me irrational, but a high profile search from a few years ago had me edgy about this place. Still, Mt Dom Dom likely to be the easiest of the three summits to activate on 2m, so the HF antenna would remain unused. I headed in from Dom Dom saddle to about point 813382 on what is marked a 4wd track but is a narrow but good 2wd track. The point where I left the car is about where Forest Explorer shows a walking track. This walking track does not exist. The southern side of Mt Dom Dom has been logged in recent years, so the growth is not too bad. I headed up the side of the mountain “following my nose”. Most of the time it was ok. I think the best approach is to head up the middle on any old logging vehicle tracks that still exist. In a few years, the whole place will be overgrown and access will have to be via the more mature forest on either side of the recently logged areas.

Here’s a look at my operating location there:

Operating location at Mt Dom Dom showing the squid pole and radio gear

Operating location at Mt Dom Dom

Action was still a little slow from Mt Dom Dom. I was getting strong reports from those who did come up from Melbourne, but there were not too many of them.

Got a nice view looking back towards Melbourne from near the summit. See if you can find my car:

Watt River valley and Melbourne from Mt Dom Dom

Watt River valley and Melbourne from Mt Dom Dom

A highlight of this activation was a QSO with Glenn VK3YY on Britannia Range VK3/VC-011. Mt Donna Buang is in the way, but we were able to get the QSO home on SSB. I’ll need to find out from Glenn what antenna he was using.

Mt Toolebewong VK3/VC-033

My final activation was actually an unplanned one, but because I was running ahead of schedule, I was able to put in for a bonus summit. Signals from here were stronger into Melbourne, as more paths were unobstructed. I had a lucky one at the end with Peter VK3ZPF, who called on 146.5 halfway through packing up, but I left the HT on. We were able to exchange reports, but I still had the colinear up in the air. This allowed us to compare the 1/4 wave “rubber ducky” with the colinear. Both ways were significantly up with the colinear.

And with that, it was time to head for home. A nice day with 4 new summits to add to the uniques collection and 18 SOTA points.

Regards, Wayne VK3WAM

Getting useful data from the MiniVNAPRO Extender

Hi all,

On a recent activation on Mt Torbreck as part of JMFD, I attempted to create a stub to tune a 70cm colinear where the antenna had been built physically too short. Tests at home showed that the feedpoint impedance was on a point on a Smith Chart where a shunt could bring it to around 50 ohms resistance.

It proved not to be. I’ve done a number of matches before, and all the theory in the world can’t be wrong. What could be wrong is the data obtained.

Overlap between the base MiniVNAPRO and Extender

The Mini radio solutions MiniVNAPRO is a vector network analyser device that operates from 100kHz up to 200MHz. It is a two port device that works in both transmission and reflection mode. Measuring antennas only makes use of the reflection mode. Transmission mode is useful for baluns and anything that does any kind of transformation.

The Extender is a device that like a transverter for the MiniVNAPRO. It effectively extends the operating frequency up to 1.5GHz. It can operate both in reflection and transmission mode, so like the base MiniVNAPRO, it is possible to both analyse antennas in reflection mode (s11 data) and transfer devices to obtain the full s11, s21, s12 and s22 data sets.

The Extender can actually report from about 50MHz up to 1.5GHz, so there is an overlap where both the base device, plus the extender can both report from 50MHz to 200MHz. This is quite useful because it can be used to check the performance of the extender. The data that is obtained should be similar to what is obtained from the base MiniVNAPRO. If the data obtained in this 50MHz to 200MHz range agrees between both devices, then data from the extender at higher ranges has at least more of a chance of being close to the mark.

Checking results on the 2m colinear

I have discussed the construction of this device before. I used the MiniVNAPRO and obtained s11 data which was then used with a smith chart tool called Linsmith to calcuate a required stub to match the antenna at 144.1 MHz. This was deployed my recent field day trip and worked well. This tells me that the data I am obtaining from the base MiniVNAPRO is good and useful for designing matching solutions.

While up at Mt Torbreck, I ran tests on the colinear which showed quite a substantial difference between the results that the base unit and the extender obtained. I did a quick test with a 50ohm standard and both the base unit plus the extender both agreed that there was a 50 ohm load. We’ll that’s fine but I need to have a good idea of what an unmatched impedance is so I can do something about it. I’m not going to need to do something that already is 50 ohms!

It would need to wait until I was back home to look at this issue further.

Environmental sensitivities in calibration

After sleeping on it for a day, I thought this problem could arise for several reasons:

1) Could be a fault with the Extender itself. Some on the net have a poor opinion about this device, but we have to rule out everything else before going here.
2) A software problem with BlueVNA. If this was true, then I could use VNA/j on the laptop and this would give substantially different results if this were true.
3) A problem with calibration in some way. It is interesting that the 50 ohm test worked ok, but non matched impedances showed substantial variances – this made me think that perhaps if something in proximity to the device when doing a calibration could impact on the open or short circuit results that could have impact practical results.

I did some tests using VNA/j and that showed some significant differences on a 2m antenna between the base MiniVNAPRO and the extender. My old calibrations were done with the unit lying on the table, but when I use it in the field, it is hanging off some antenna in free space. Perhaps I should try to do calibrations again holding the unit up in the air.

After doing this, I noticed that there was a shift in the results obtained. Calibrating the MiniVNAPRO with extender lying on the table does not seem a good idea. My table at home is wood, but has metal bracing underneath the surface. Still after holding the unit in the air did not bring agreed results, but one set was within 10%. Good, but could be better.

In the end, I grabbed on of those in car phone holders that have a suction cup to go on a car windscreen. I put one of these on my desk and used it to hold the device during calibrations. I also found that there is benefit doing an average calibation – 3 to 5 passes. Most of the benefit is obtained with 3. There is little point to a greater number of passes such as 10.

2m Jpole results using VNA/j with USB interface

Here is a smith chart plot of results obtained on a 2m jpole that is a little long – both in the results obtained here, and in real life.

Smith chart result of 2m Jpole using VNA/j with MiniVNAPRO

2m Jpole using VNA/j with MiniVNAPRO

Smith chart results of 2m Jpole using VNA/j with MiniVNAPRO Extender

2m Jpole using VNA/j with MiniVNAPRO Extender

We can see that the results are quite close. They aren’t exactly the same but they are much closer than the results I was previously obtaining. One thing I could observe is that the better dynamic range of the base unit does show through. Also, I used 20,000 calibration steps for both calibrations. On the extender, the steps are nearly 8 times further apart than for the base unit.

Still these results are close enough that these extender results are useful.

2m Jpole results using BlueVNA with Bluetooth interface

With the VNA/j results giving me greater confidence, I then moved over to look at BlueVNA. BlueVNA does not allow averaging of calibration data. I still tried doing the calibration in the phone holder. Here is what the Jpole looked like in BlueVNA.

Smith chart results of 2m Jpole using BlueVNA with MiniVNAPRO

2m Jpole using BlueVNA with MiniVNAPRO

Smith chart results of 2m Jpole using BlueVNA with MiniVNAPRO Extender

2m Jpole using BlueVNA with MiniVNAPRO Extender

Firstly, the results broadly match, both with the base unit and with the extender. The basic line on all four charts is the same. One thing that I have noticed is that the “noise” in the data is higher with these results. In terms of quality I would rank them from best to worse as follows:

1) MiniVNAPRO with USB
2) MiniVNAPRO with Bluetooth
3) MINIVNAPRO Extender with USB
4) MINIVNAPRO Extender with Bluetooth.

Having said that, all four results are quite usable, so I think I have got on top of this problem for now. Obviously I cannot compare the base unit at 70cm as only the Extender works there, but perhaps I could compare USB mode against Bluetooth. We’ll see how that goes with the 70cm colinear that I’ll still see if I can match it at 439 MHz.

73 and regards, Wayne VK3WAM