Saturday the 21st of June saw the Trans Tasman contest on 160m phone and 160/80m CW and digital on. It was a 6 hour contest with the best 5 hours to count.
The Eastern Mountain District Radio Club (EMDRC) was going to enter this, so I thought I would get involved doing CW and digital. I have a SignaLink USB on my FT-897 at home and so I put my hand up to focus on 80m.
Operating Station setup
I would have liked to have posted photos on this post, but I was busy contesting. Someone else took some photos, so hopefully they will show the station and I will edit this post at a future time.
My operating station consisted of my FT-897 brought in from home, a MFJ1025 noise canceller, a MFJ T-match manual tuner, a LDG ZPro-II auto tuner and the SingaLink USB. The antenna was an inverted-V full length for 80 metres. I had low SWR on the antenna without using the T-match, but found I had significantly less interference from 160m operations if I left the tuner in.
What was the ZPro doing? I had this tune a 20 metre beam for 80m to use as a noise sense antenna for the MFJ noise canceller. This seemed to work. The noise canceller was not able to lower the general noise floor, but what it was good for was getting rid of specific QRM that appeared throughout the night. The ZPro was affected by RF in the shack from 160m operations, so I had to put it in manual mode to not try to retune every time there was a 160m operation. I wonder what I was exposing myself to in the shack last night!
The EMDRC has been encouraging members to use Anderson poles There is nowhere in the shack to plug them in however, so lucky I brought a cable with rings on one end and Anderson Poles on the other. I still had to wedge these in to the power supply as it wanted lugs, but oh-well. It worked and I was able to use Anderson Poles for the rest. From the converter, I had a 3 way Y-plug, with the FT-897 plugged into this. I had a second 3 way y-plug, which was a little overkill, but plugged into this was the ZPro and the noise canceller. I could have easily plugged in 2 more things if required – so the setup is very flexible for use here at the EMDRC away from my own shack, and also for my QRO and QRP SOTA setups.
Digital modes that are AFSK based – i.e. all of them where a sound card is used to feed a SSB type mode on a typical rig – need the rig to stay as linear as possible. It is very important that there is no processor or ALC action. I had my rig showing ALC on its meter and increased TX level as much as possible, but not so much to activate the ALC. On the SignaLink, this ended up being around “10am” on the TX potentiometer. Other stations were transmitting with clear ALC action on their signal. This causes splatter. One station had so much splatter on their PSK31 signal that it was taking up nearly a full 1KHz for a signal that is supposed to only take 31Hz. This is multiple orders of intermodulation! I could not decode this signal – and sent them a message to turn down their TX! They did so, and while the splatter was still bad, it was at least then decode-able. A number had one order of splatter – giving a head and shoulders look. You want all of your TX energy in what is supposed to be there, and the shoulders are a waste of energy. A few stations had PSK-31 stations that had no observable splatter.
PSK31 does not tolerate almost any drift. Even on 80m there was one particular station that drifted 10Hz or so, and this was enough to cause decoding to stop until I re-clicked on the signal to move the decoding bars. This has implications for use of PSK on higher bands, especially VHF/UHF where this issue would be more critical. Some have suggested for this reason that PSK is not suitable for VHF work.
In the end, I worked like a slave for the full 6 hours. My software was not that good at decoding CW, so lucky my brain can at least reasonably decode 20wpm. I operated the first 20 minutes or so of each hour CW, then the middle 20 minutes digital and the last 20 minutes CW again. The rules allowed for digital stations to be re-worked every half hour (once in the first half hour, and again in the second half hour), so I tried to take advantage of this – which mostly I was able to.
Most contest digital ops where PSK31. There was some RTTY near the start and occasionally later. One station was using Hell, but I had already worked them in that time slot. The key with Hell is to turn the software “squelch” all the way down. Hell is like reading a fax – the signal processing is in your brain.
In the end, contest activity was reasonably engaging. I found running got more contacts, so I spent about 75% of the time running. It was the first time ever that I had actually chased CW stations. This is because when I activate CW in SOTA, I am always the “running” station. I picked up the chaser caper without too much trouble. Of course in CW, one should not transmit on the running stations frequency, but offset 100Hz or so.
Having a narrow IF filter defiantly helps in both CW and digital. I would normally operate using the wide filter, but if something was happening 1KHz away that would affect the AGL, then I could quickly switch to the 300Hz Collins filter to get rid of it. The wide filter is good for seeing a broad picture on the waterfall when AGL action is not taking away the signal that I am interested in. I left the FT-897 menu on the selection where I could switch between the two filters with one press of the button.
In the end, it was an enjoyable contest. I had 87 non DUP contacts (1 DUP), so not too bad for a first effort.