Candid 4m Write-up by Daniel M0ERA


4m: A nice relaxing day on the "Gentleman's band".  Shame, really.

Sunday morning: It was a fantastic day, with a beautiful sunrise after a good (albeit short) night on site.  Even early in the morning it was hot, but with a refreshing breeze.  The high pressure system has been over Great Britain and Central Europe for more than a week now, with lots of tropo enhancement.  Only yesterday, there had been sporadic E openings on 70MHz to Portugal!  And fortunately, it was not humid, so there was no threat of thunderstorms.  A great day for contesting!  And thanks to my older brother David, I had a fancy long-sleeved T-shirt protecting myself from the sun.

To make things even better, life was very comfortable: a reliable generator, tents to protect against the sun, plenty of water, strong tea and coffee prepared on the petrol burner, and fresh croissants (Thanks Belinda!).

At 06:00z, two hours before the contest, I started calling CQ to warm up the band.  Surprisingly, there were quite a few replies.  I got five new squares, "excellent audio" reports and had two ragchews with Scottish stations also preparing for the contest. Already more than 1200 points lined up - this was going to be good! I only hoped that we were not going to miss any sporadic Es to Portugal.  But there was the packet cluster to sort that out.

14:00z, eight hours later: We made it, but we have only seven hundred claimed points more than last year. The plan was to double the score.  The band conditions were good, so what happened?  We made a number of mistakes wrecking our performance.  Just minutes before the start, we realised that my home brew low pass filter was not good enough for the contest.  So we decided not to use the shiny new Spectrum Communications transverter with the 28MHz IF and the SGC SG-2020 to drive it, but to resort to our backup equipment: a RN transverter to 145MHz and a FT290R.  At least, the RN transverter didn't need an external low pass filter.  But we paid for that... Some lessons to be learned:

The 4m packet works very well and is a good tool to see what is going on during the contest.  No major sporadic E or tropo duct is going to be missed!  Of course, that only works if we have a frequency to run (and maybe additionally search and pounce at the same time).  Thanks to Michael and Fred for the support!  It was very generous of Michael to donate the AKD rig.  The necessary equipment is simple to set up.  It will be a fantastic tool for the 144 MHz contests (even for the Practical Wireless QRP event next year).  We should also install the cluster connection in the club shack.

However, it is not a good idea to run a 4m packet cluster and a 4m SSB station on the same site.  Although the packet station only transmits short bursts, it triggers the AGC of the contest receiver.  It sounds like "plop".  And there are plenty of these bursts.  As a result, our ODX came over as "location is IO75c-plop... repeat IO75-plop".  You need a lot of perseverance to work under these conditions!  It is easier to check the beacons for change of propagation than to suffer from that kind of QRM.  The 4m DX Of The Day (to LX, OZ and S5) were not spotted anyhow.  If we want a cluster connection on the next VHF NFD, we should either use the microwaves for the link or not bother with the 4m event.

It also is not a good idea to use a transverter with an IF on 2m.  The breakthrough from the 2m station next door is S9+10, and it sounds just like that elusive Danish station on the adjacent frequency.  We wasted much time chasing ghost stations!

The FT290R is not good enough for the CW traffic on 4m (and there is plenty).  It has no transmit/receive changeover switch, no suitable filter and the PLL steps are too wide.  We lost all of our CW QSOs in co-channel QRM.  However, to our surprise, it worked well to call the stations using SSB and have a chat.  But even on SSB, we kept getting comments about the poor audio quality.

The beam is very old design, and we can easily improve the performance of the station by using a modern yagi (there are really interesting designs with 7 elements out there).  When putting the dimensions of our 5 ele yagi into EZNEC, I get a front/back ratio of only 8dB.  No wonder we get about half of our contacts on the back of the beam.

We need to pay close attention to the computers on site.  My HP laptop, which was running the DX cluster, produces an awful sound on 4m.  But only just before the end of the contest, we realised where the QRN came from.  Strangely, the laptop was quiet when we started.  Maybe the level of noise changes when the battery is fully charged.

All in all, it was a nice relaxing day out.  But that wasn't the idea of the contest!  We need to improve the station if we want more points (a working low pass filter will be a good start).  On the other hand, it is amazing how far we got with all these self-made problems.  Maybe that is the real point of the National Field Day: to provide reliable communications in a sub-optimal environment.  But next year, we don't need to train ourselves for a disaster (we have done that now), but get serious about contesting.

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