Concurso Combinado V-UHF 2016

This weekend, being the first weekend in March, marks the start of the Spanish V-UHF contest season for this year. In previous years, I've been operating casually in some of these contests as a portable station. Sometimes I've worked on the countryside just outside my town, Tres Cantos, and on other occasions I've being enjoying the contest from a summit while doing a SOTA activation. My plan for this year is to participate in all (or almost all) of the contests and try to work from a summit as many times as I can. I pretend to work QRP (5 Watts) always and enter the 6-hour category, which allows working for a maximum of 6 consecutive hours.

Today, I've worked in the Concurso Combinado V-UHF. The weather forecast was too windy and cold to stay for several hours on a summit, so I decided to work from the countryside near town. I've worked this morning from 09:00UTC to 12:00UTC more or less. The equipment was, as usual, an FT-817ND and an Arrow satellite yagi antenna (3 elements on 144MHz and 7 elements on 432MHz). See below for a map of the stations worked. My position is marked in red, the stations worked in 144MHz only are marked in blue and the stations worked in both 144MHz and 432MHz are marked in green.

My position on the map is accurate, but the positions of the other stations are just taken from their 6 digit locator. The map has been generated essentially by hand. Perhaps I'll write some software in the future to automate this a bit.

In this contest I was testing some new equipment in the field for the first time. I was using a new camera tripod to hold my Arrow antenna. The nice thing about this new tripod is that its camera mount can be tilted 90º. This allows me to switch to the 432MHz yagi while maintaining horizontal polarization (the two yagis are on orthogonal planes). However, this trick didn't work as expected, because the thread in the camera mount didn't hold the antenna tight enough and it had to be held by hand. This probably explains why I didn't manage to work any good DX on 432MHz, as operating in this position was very uncomfortable. Indeed, many of the 432MHz contacts where done in the vertical polarization. I've modified the camera mount to solve this problem.

I was also using a computer headset instead of the usual hand mike. This setup has been in use in the shack for some months, but it was the first time I took it to the field. This morning it was quite windy at times, and another station reported that he thought that perhaps there was some problem with my equipment, since I sounded as if I was standing in the middle of a gale. I told him that I was working portable and I was literally in such a gale. Blocking the wind with the paper logbook seemed to make a good improvement.

I use a modified DYC-8x7 speech compressor to interface the headset with the FT-817ND. I was planning to operate until the contest end at 14:00UTC, but I had to finish early because the mic connection failed. The jack where I plug the mic was a bit loose and eventually one of the wires that connects it to the compressor PCB broke at the solder joint. This is something that is very easy to fix at the shack but impossible to deal with in the field. I have already fixed this and carefully glued the jack in place to prevent this from happening again.

Another thing to improve in the contest next month are the coax connections between the radio and antenna. In this contest I used one of the coax cables that I use for working satellites. It is a 120cm RG-58 coax, which is appropriate when the Arrow is hand-held. However, it is a bit short when the Arrow is held on a tripod. Moreover, the coax has to be switched to the 432MHz yagi when changing bands, and this is a bit awkward to do while wearing gloves. I think that a pair of 200cm cables will be much better, as I can connect the 144MHz yagi to the SO-239 connector in the FT-817ND and the 432MHz yagi to the BNC connector. I also have some spare Airborne 5, so this will be a small improvement over regular RG-58 coax.

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