QRP Lessons from the ARRL 10M Contest

Operating QRP is not typical behaviour for someone with a station in the so-called "big gun" class. I used to do all my operating as QRP and the pleasure of it has never abandonned me. It may seem odd to put 5 watts into big antennas, and yet it is a lot of fun. If you scan the results of any major contest you will notice that I am not the only one doing it.

But why QRP in the ARRL 10 Meter contest? My interest in the contest is limited and I needed a way to spice it up if I was to bother. Hams with small stations -- be it power or antennas -- know that the high bands make working stations easier due to the low atmospheric noise. Of course the MUF has to be high enough to make it possible. A solar maximum is the ideal time to have fun on 10 meters.

To answer my own question, I operated QRP in this contest for two reasons. One was that the pace is less hectic than with high power due to the pile ups a big signal attracts. The second is that it was an interesting test of how my antennas perform. With a solar flux of about 125, 10 meters was open but marginal over many paths. That means a few decibels can have a large impact on results. So I put the antennas (and myself) to the test.

To recap, I have 4 antennas on 10 meters:

• 5 element yagi at 34 meters fixed to Europe (lower yagi of the 10 meter stack)
  
• 5 element yagi at 46 meters, rotatable (upper yagi of the 10 meter stack)
  
• Skyhawk tri-bander at 21 meters, rotatable
• TH6 tri-bander at 25 meters, fixed south

It is handy to have all of these directional antennas on 10; I didn't need to rotate the rotatable antennas often. Just click the mouse to select an antenna and then call the station.

This was my first contest using the recently purchased Icom 7610 as my primary rig. After CQ WW SSB, I switched the transceivers so that the FTdx5000 is now the second radio, positioned on the operator's right. Getting used to the 7610 was a secondary objective for the 10 meter contest. It was a stretch for me to quickly learn how to use the 7610 for SO2V operation. To avoid the hassle I reverted to SO1R and used the second VFO/receiver to tune stations. I swapped the VFOs when I wanted to call a station during my occasional runs.

The 7610's power setting is measured in percent of full power (nominally 100 watts). That made me suspicious of the actual power output so I used a power meter to measure the power at various settings. The power percentage does not perfectly track the power output, although it is close. It varies by band and across the power range. For this contest I chose a setting that gave a power of slightly below 5 watts on the 10 meter band. At least this is more convenient that the 3 db attenuator I built to use the FTdx5000 on QRP due its 10 watt minimum power setting.

Conditions at the start of the contest on Friday evening were poor. It was well past sunset and few signals were to be found. Those that I did hear were weak and not really worth calling with QRP. I put off operating until Saturday morning. I got up early to catch the sunrise opening. Although many Europeans were heard before sunrise their signals were weak. I had to wait until signals became stronger. I began filling the log soon after 1230Z. 

Europe was coming in strong and it was easy to work stations with 5 watts and the 5-over-5 stack. Indeed, Europe was the source of about half my contest contacts and the bulk of the multipliers (65 countries overall). That is despite the brief openings. I was able to get as far as UA, UR, 4X and 5Z. By late morning the Europeans faded to only a trickle of stations in F, EA and CT. The path closed soon after their local sunset.

The rest of the day was spent hunting stations to the south, and later to the west. I could run Europeans with QRP but runs were painfully brief to the US and I frequently lost my run frequency to North American stations that couldn't hear me. However, running is mandatory, even with QRP. If you don't it is impossible to work the large number of casual contesters who only S & P. I kept my run attempts brief but frequent.

Propagation under the marginal conditions was intriguing. The most important aspect was the large size of the skip zone. It was both a curse and a blessing, as I'll describe. The map above is my attempt to illustrate my observations, and my successes and failures.

Stations at the edge of the skip zone would be S0 one minute and S9 the next. It was very evident with MN and MB to the west and W5 and W0 to the southwest. It was a lot like sporadic E openings on 6 meters, except that sporadic E, also a staple on 10 meters, did not appear to be evidence despite the nearness of the winter season peak.

As a QRP operator I had to check station signal levels often to catch those peaks to increment my small total of state and province multipliers. This is where entering the assisted class came in handy. I could rapidly check on stations with a click of the mouse. I used both human and skimmer spots.

Particularly galling was that I was shut out of most of W4, other than Florida. That is the reason my state and province total of 49 multipliers was so low. I missed GA, TN, AL and KY. I heard many of them but weakly on back scatter. Unlike W1/2/3/8/9 stations that I could work on back scatter (mostly just the big guns), the added distance to W4 made it too difficult for QRP. W5, W6 and W7 were easy to work most of the time. The same with the western provinces from VE4 to VE7. A few Maritime provinces were workable on back scatter but, again, I missed most of those multipliers.

That's the con. Now for the pro case. Everyone has a skip zone centred on their QTH. For the bulk of the US eastern seaboard and south, they were at a relative disadvantage working the Caribbean and, occasionally, Central America and the north coast of South America. There aren't many stations there but almost every one is a multiplier. There were many times when I could sail over their skip zone and work those stations, right through modest pile ups. That was only in the morning because in the afternoon I could not compete with those further to the west that were in a similar relative position to me. Skip went long early as the MUF fell.

Back scatter was a puzzle that I had to solve since signals are very weak in comparison to the direct propagation path. QRP is not conducive to effective communication via back scatter. Yet it is the only option to reach stations within the skip zone. Every attempt was a roll of the dice and I had to find a way to increase the probability of success. Sometimes it was simply of matter of trying every few minutes to hopefully catch a small upward variation of the scattered signal strength. 

Calling a big gun has the best chance of success on back scatter since they have the antenna gain to better hear my signal. Unless you recognize the call signs of those stations you can only go by what the S-meter tells you. Obviously, the stronger you hear them, the better.

Equally important is listening to who they're working. That tells you where their yagis are pointed. Your best chance of success on back scatter is to point in the same direction that they are. Sometimes that is northeast to Europe and other times it's south to the Caribbean or west to the Pacific. That's true no matter where the target station is located. Early in the day when the band was open to Europe, northeast was best. That suited me well since my 10 meter stack is most effective in that direction. 

With four antennas at my disposal and the ability to point in various directions, it was a simple matter of clicking through the options and seeing which antenna netted the strongest signal. Then I call and hopefully work them. When you have only one antenna, testing the back scatter path by constantly rotating the antenna is time consuming. The wealth of antennas was highly advantageous.

I decided early on Saturday to change my operating plan to better utilize the propagation that was available. I had intended to operate mixed mode (SSB and CW). Since signals levels were generally poor I decided to stick with CW. I certainly would have had a higher score operating both modes, although I suspect that I would have been less competitive. Due to the lack of daylight at this latitude, the openings were shorter. Stations further south had the advantage since they experienced a higher MUF. Their advantage is greater with SSB due to the lower SNR.

Late in the afternoon the band opens to the Pacific and east Asia. The pile ups on the few VK stations were intense. I had to wait for their rates to drop before I had a chance. With no other callers it was no problem to work them. The same can't be said for Japan and stations further west on mainland Asia. The low solar flux had the band closing soon after sunset, which is nearly coincident with our sunrise. Signals were weak and not workable with QRP, even with 5 elements 46 meters up. Very soon they were gone. I heard long path Asian stations in the morning that were also unworkable with QRP.

Was I competitive? Did I win? Reports on 3830 suggest that I may come out on top in CW QRP (unlimited/assisted). Not everyone posts on 3830 and scores will change after log checking. I didn't set out to win, just to have fun and test the station. It would be nice to win even though that was not my objective. Time will tell.