VWS Field Day 2017

Photo of VWS field day site including multiple operating positions.
Antennas set up at VWS Field Day 2017: the mobile-mounted VHF station (left) and multiband hexbeam HF station (right).

Over the summer, I managed to get back to Virginia just in time for ARRL Field Day with the Vienna Wireless Society. The trip itself wore me down – I had just spent a few weeks in the US, returned to Madagacar for a week (just long enough to get back on local time), and then back to the US for Field Day. However, because my brain was still on East Africa Time, I was unusually perky for the midnight to 8 am shift on 80m.

Our best year yet

Our numbers were just compiled and reviewed at the last club meeting; a really polished analysis is available online.  This year we did much better than last year; this year’s score of 12,302 points blew past the club’s 2009 all time record of 10,958 as a class 4A station. We essentially doubled the QSO count from the prior year, with all four stations pulling hard through the night to keep up the rate.

This was the second year that Mike, KA4CDN, served as FD trail boss, and the prior year’s experience no doubt helped everything run smoothly. Earlier in the year, the club’s Quartermaster, Mel, KI4WKZ, undertook the monumental task of organizing the club’s storage locker and creating an inventory management system for the pile of antennas, wires, rigs, and accumulated detritus owned by the club. He described this effort in a video. Largely thanks to his work, this year it was easy to find everything: all the plastic containers were labelled, and what was supposed to be in them actually *was* in them. It made field day deployment a pleasure.

The icing on the cake was new tents for the operating positions and central admin tent. The old tents were feeling their age. The new ones went up much easier than the previous generation and had removable side panels. Previously, when weather turned sour, the best we could do was to cover the tents in plastic tarp since the sides were open, but now we can operate through a substantial downpour. The removable side panels are just as important in the hot and muggy Virginia summer, since they allow ventilation, but also can be re-positioned as the sun moves to keep screens readable.

The 20/80 Data/CW Station

This year, we had a Flex rig set up for Data and CW on 20/80 meters, with choice of mode left up to the operator. A few years ago, we tried running data, and there were very few contacts on digital. This year, the number of contacts was up and included both PSK31 and RTTY. It still seems like there are a lot more CW operators than digital, but rate may also be an issue as it seems like data mode exchanges take longer, particularly if wordy macros are used. Over time, I would expect data modes to continue to gain in popularity. If the club does not have enough CW operators to continually staff the CW stations, it makes sense to fill schedule gaps with data mode. However, if there are enough CW ops, going 5A with a dedicated digital mode station may also be a good solution and allow the greatest number of club members to operate, regardless of skill with the paddles.

80m CW station at 4 am. If it is blurry, that’s accurate.

The 20/80 CW station was also significant for running an SDR as a contest rig. I thought the Flex rig integrated very well with N1MM, with no delay on paddle sending and only slight inter-character delay when sending from the keyboard. One laptop was handling both the rig and N1MM, which may account for that minimal delay. I did not have to use the Flex’s full filtering capability, and chose to keep the filter at about 400 Hz. I spent most of the time calling, but appreciated the waterfall display for both finding clear frequencies to call, and for spotting flighty stations when in S&P.

The CW tent, lawn, and sky. A flag hangs from the spiderbeam to the right of the tent.
Dawn over the 80m CW station.

Antenna Thoughts

Now that the event is over, thoughts turn to improvements for next year. One that has been batted about is high-band antennas. This year, we had a hexbeam and spiderbeam for SSB and CW, respectively. These worked well, providing some gain westward, with some reduction in off-beam interference. Because these are slightly less than 2-element beams, they also hear relatively well off the sides, so there was no need to rotate them to hear, for example, Florida stations. Despite their excellent performance, I’ve wondered whether it would make sense to go to band-specific 3-element beams for subsequent field days during the solar minimum.

In principle, the multiband antennas that we have enable use to jump on openings on 10m or even 6m. This chance is improved with Flex or similar rigs that can monitor these bands while operating on another band. However, the chances for such openings are less and less as we approach solar minimum, and the VHF station already covers 6m.

Here are my arguments for considering a three element beam: Our goal is to hit as many FD stations as possible. The number of sections doesn’t matter, as it is not a multiplier. I mapped out where those stations are using data from the list of stations that submitted logs in 2016.  On 20m, the big players are FL, TX, and generally the west coast, which accords with the general distribution of hams in the US:

Map of US State and Canadian Provinces and Territories
Map of FD sites based on 2016 logs submitted

Referring to an azimuthal projection from the FD site, the entire west coast falls between 270 and 300 degrees. All of Texas falls between 240 and 270.

For the antennas under consideration:

Type Forward Gain (dBd) Half-power beam width
Moxon 4 80 degrees
Hexbeam 3.8 90 degrees
3-ele yagi 7.5 60 degrees

So, the 3 ele-yagi could hit the arc from TX through Washington with up to a bit more than twice the power of our current set up. This year, west coast stations were relatively weak on 20m. Florida would fall to the side of the forward lobe, but the power radiated in that direction would be roughly on par with what we have now since we’re starting from higher gain; also, FL is closer than west coast, so less loss over distance.

In principle, adding an amp for another 50W gets us 1.7dB, but we gain at least 3.5 dB by adding an antenna element (or do both, 5.2 dB, almost an S-unit).

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