Two SOTA summits activated for VHF/UHF winter field day

I thought it would be interesting to be within reach of the Sydney and Blue Mountains areas  for this contest.  The Illawarra and Central Tablelands regions are the obvious choices.  I decided to go to Mt Wanganderry, Mt Alexandra and Mt Gibraltar and I optimistically planned to spend about an hour on each, which with travel time would probably consume 6 hours, assuming I was on site for the first summit at the start of the contest at 11 am local time, 0100 UTC.

The bands I could use in my FT817 were 50, 144 and 432 MHz.  Adding a SGLAB transverter I could extend that to 1296 MHz.  Antennas were

  • for 50 MHz, a half wave centre fed vertical in the configuration of a coaxial dipole, with a choke at the half wave point and another a quarter wave lower than the first choke.
  • for 144 and 432 MHz I used a horizontal wire dipole attached to two fibreglass spreaders, mounted onto the fibreglass mast using a hub
  • for 1296 MHz the antenna was a 4 element yagi, with the transverter mounted as close as possible to minimise losses in the RG58 coaxial cable.
    the 6m vertical above the 2m/70cm dipole mounted on the pole

    More detail of the 2m dipole with a CATV BNC/wire terminal adaptor at the feedpoint

I logged my contacts using the VK Port-a-log software on a Lenovo 7 inch tablet computer.  I had the option of trying the latest contest version of this package but the designer Peter VK3ZPF was concerned that the 2 hour repeat contact rule for this contest would not be accepted by the nearest contest option in the contest version.  So I decided to use the standard parks and peaks version of the package.  This worked but required a bit of scrolling up and down to find the gridsquare field when logging the details of each contact made.

The 6m/2m/70cm equipment, an FT817

After reaching the site later than ideal, around 12:30 local time, I set up the antennas and equipment.  To comply with SOTA rules my gear was powered by batteries and the entire station was portable and independent of the car.

The second FT817 was used for 1296 mhz contacts via the transverter
1296 transverter and antenna mounted on the camera tripod

I made some initial contacts on the lower bands followed by some attempted contacts with Tim VK2XAX on 1296 MHz SSB.  I could hear Tim but my 2.5w apparently wasn’t enough for him to hear me.  Then there was a good contact with Mike Vk2FLR close to the Sydney CBD, 96km away.

I was about to close the site and move to the next one when I noticed one of my tyres was flat and I needed to change it before I could move.  After changing the tyre I was able to make repeat contacts with several of the stations I had worked earlier, so I had been there at least 2 hours by that time.  (Not keeping to plan too well.)

But finally by 3:15pm I set off for the next summit, Mt Alexandra, about 20km away.  It is located directly to the north of the residental streets of Mittagong with a parking area at the end of a bush track leading up past the houses.  After packing the bag and hefting the antenna poles, tripod and 2nd FT817, I walked over to the start of the climb up the hill only to find a sign advising that the track was under repair and would not reopen until late July.  So I returned to the car, unpacked it all and set off for Mt Gibraltar, which was now my second and final summit for the day, arriving at about 4pm local time.

Setting up to the east of the first cyclone fenced compound, I was able to replicate my earlier setup fairly quickly and get onto the lower three bands. Connecting up the 1296 transverter and antenna, I found a very strong signal again from the VK2RSY beacon on 1296.420, then made a good contact with Mike VK2FLR albeit at lower signal levels than from the first location.  I don’t know whether I had changed something significant, or there was a connector problem, but signals were not as good as they had been.  There were trees obstructing the view towards Sydney so perhaps they were attenuating signals on 1296.  The distance was slightly shorter than the earlier contact, about 91km.

After uploading my log to the home computer, I found I had made 27 contacts but it is possible one of my contacts was made too early for a valid repeat.

On balance I think this operation confirmed that even a low power radio (5W) can be used effectively from a good location in these events.  I hope others who own similar radios and can make similar (very) simple antennas will be encouraged by these results and participate in future.  I think hearing strong signals on the VHF and higher bands is still fascinating to me and far more interesting than a totally predictable and reliable contact via a repeater.

4 thoughts on “Two SOTA summits activated for VHF/UHF winter field day

  1. An interesting day Andrew and well done for giving it a go. 27 contacts isnt to be sneezed at …sometimes I have only made a couple from my home station :0) . I couldn’t make it this time round as it clashed with a 1 in a 100 year event – my Aunty becoming a centenarian and wasnt on the road back until well after the event.

  2. The pole mounting sleeve and the boom mounting collar also made it to the event, thanks to you!

  3. Although 5 watts and ultra simple antennas can’t be expected to work as well as my usual field station, it was enough for me to have some fun and give the Sydney ops a signal to look for. Always interesting to see how directive a dipole can be. At 4m above ground, 2 wavelengths, that is how a 40m dipole would work at a height of 80m!! Congrats to your Aunty, how wonderful.

Comments are closed.