2013 Winter VHF/UHF Field Day

22nd June 2013


This has been the first VHF/UHF Field Day for a while that I haven’t gone out and set up a portable station – but I do have a reasonable excuse. Realistically, I was almost portable even if it was from the ‘new’ back yard at QG62LG51.

We moved the home QTH just 3 weeks beforehand and at least some of the normal FD station gear is somewhere in the shed, not quite sure exactly where in some cases. The trailer that I normally use as a “shack” for these events has been in almost continual use for the last 5+ weeks ferrying rubbish to the dump and belongings from the old QTH to the new one so one of the rotators had been removed so that it wouldn’t get damaged. It would only have taken a short time to re-mount it but I wasn’t going to have the opportunity to set up in the field this time around anyway.

The only alternative was to set up my set of turnstile antennas (horizontally polarized crossed dipoles for those of you who don’t know what a turnstile is) for 6M, 2M and 70CM plus a Diamond SG7400 dual band 2M/70CM vertical whip as an alternative antenna for the event, mounted on a 6M long thin-wall galvanised pipe roped to a vertical post on the afore-mentioned shed. A later thought led me to set up a 70CM home-brew collinear whip on a shorter pipe (3M) and rope it to another vertical shed post.

The radio gear was a switch-mode 12V power supply powering the IC-706MK2G transceiver for 6M (to the antenna via a LDG Z-100 auto ATU), and then via a coax switch for 2M and 70CM. I also had a Yaesu FT-1802M 2M mobile set up for 146.500 simplex (using the SG7400 whip) and an IC-249 70CM mobile set up for 439.000 simplex (using the homebrew collinear), all powered off the same power supply. There was no microwave gear set up this time, it is all “somewhere in the shed”.

The “portable shack” was the family caravan parked under the awning of the shed, which was just as well as it wasn’t too warm even here just south of Brisbane, and at least the van was reasonably draught-free. I guess that if I had run the radios off the internal 12V supply in the van itself, I really would really have been able to enter the portable category

The “best plans” still come unstuck even when operating a temporary setup from home in lieu of the top of some mountain somewhere, the difference being that you generally have access to the bit you need to solve the problems. In this case, the SWR on the 2M turnstile was high (if you call >4:1 high) so I elected to drop the mast tube to connect another feeder in lieu of the original one. A search through the piles of coax in the shed provided a suitable length of RG213-sized cable with N-connectors at each end so it was duly fitted. That partially solved the SWR issue in that it was now 2:1 and with the FD due to start in about ¾ hour time, that was going to have to do. Up went the mast pole again, tied in place with the rope and the SWR  rechecked – yes, still around 2:1. Perchance I also checked the 70CM turnstile at that point in time and it was up around 5:1 where beforehand it was down around 1.6:1, but with time running out, that was going to have to do.  That SWR result is now on the list of things-to-be-checked before the next time it is used…..

The other issue that I noted was the presence of wide-band noise due to the mains power adapter for the Asus Netbook, it being bad enough to make me do this event using a paper log. Pity I didn’t think to unplug it and just run off the internal battery and then re-charge it during my “off” periods, but hindsight is wonderful isn’t it ?

The FD kicked off on the Saturday at 12PM local, 0200Z, and within a few minutes I had made contacts on 6M, 2M and 70CM, SSB and FM. The initial list of stations soon dwindled such that there weren’t any that I hadn’t worked that I could work so I took a break to do other things and returned just on 3 hours later for the re-work option. It was during this period that I weakly heard Grant VK2MAX on my turnstile on 2M SSB, a phenomenal occurrence for a 375Km path, given I had no effective antenna gain, or least of all any directional gain. It bodes well for this new QTH though.

I returned again after 6PM local to provide a few more re-contacts and then departed my “shack” again. Pity I hadn’t read the rules for home stations beforehand because I could have handed out some more numbers on the Sunday morning, but here I was, expecting to enter an 8 hour home station segment only to find that there isn’t one !!

My efforts resulted in 57 contacts, two of which were non-scoring due to timing issues (and I can only blame myself and the paper log method for these), with a nominal score of 513 points.

If nothing else, this event gave me a good idea what I can expect to work on VHF/UHF/microwave from this new QTH.


Mouse-over to see the images larger...



The family caravan used as a "shack for this field day


Only a small radio setup this time, mains power supply at bottom, IC-706MK2G above, LDG Z-100 ATU, IC-249 then finally, on top, a FT-1802M. Asus Netbook at the RHS for logging - which, as it turns out, wasn't used due to power supply noise.


70CM homebrew collinear in foreground, top of the turnstile set in the background.


Better view of the antennas..