P40L-P49Y Contest Summary Information

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10 meters delighted us in the 2010 CQ WW RTTY contest by supporting some QSOs. This past weekend it dazzled us, providing worldwide propagation just like some remember from the last solar high. For newer contesters the 10 meter band must have seemed mystical. The extent to which 10 meters was really back is demonstrated by how poor the lower bands performed with the MUF so high. 20 meters seemed virtually blacked out at times during the day while 10 and 15 were jammed with QSOs. At night, 40 and especially 80 were big disappointments compared to how they've been in recent years with the last solar cycle low.

This dramatic shift in bands was undoubtedly accentuated by migration of activity to the higher bands. In Aruba, 10 and 15 were open before local sunrise and held up well past local sunset. There were periods of diminished signal levels, close to blackouts, particularly on Saturday, where signals faded into the noise floor mid-QSO. These temporal blackouts were forecast along with the solar activity.

CQ WW RTTY records surely fell as a result of this long-awaited high-band propagation. Because RTTY contest participation is so much higher than at prior solar peaks, it is hard to predict just how high contest records can be pushed. Clearly, though, one limitation is QSO rates which in turn are contrained by the excessively long messages being sent. Until the majority of participants evolve to short exchanges as in CW and SSB contesting, maximum QSO rates will be stuck at just over 100/hour per radio.

P49X operated M2 with K6AW on 15/80, W6OTC on 20 and W0YK on 10/40. N4RR rotated between the three positions to give everyone a 3-hour break every nine hours. 10 meters had been so outstanding the days prior to the contest that we decided to start on 10 and 15, switching to 20 when 10 dropped off. After the first half-hour, the rate on 10 did drop, or at least it faltered, so we moved to 20. 15 wasn't moved to 40 until the third hour Friday. On Saturday, the band changes occurred earlier and on Sunday we left 10 more than three hours earlier than Friday, finishing the contest on 15 and 20. Sunday afternoon was blessed by nearly every QSO coming from Europeans who had not yet been in our log on any band. We encouraged each to go to the other band (10 or 15) and many did. Because of this and other aspects of the highly skewed high-band proportion of QSOs, for the first time at P49X, more QSOs were made with Europe than North America.

The station setup used my SO3R configuration which is three networked computers, one on each of three radios (Elecraft K3s). For this M2 we dedicated radios to bands: 10/40, 15/80 and 20. The K3 Band Map feature was used to enable only those bands on each radio, minimizing the chance to inadvertently get on the wrong band. We replaced the ICE419 bandpass filters with individual W3NQN filters which N4RR brought. This required manual swapping of band pass filters on the 10/40 and 15/80 positions. Band changes were simply executed by stopping operation at one position and starting on another. There were few, if any, times when we were band changing between 15 and 80 or 10 and 40.

Forseeing that there could be significant 10 meter operation, Elecraft built two prototype pre-amps based on their PR6 6-meter preamp which is fully integrated with the K3. It was engaged on the 10-meter position almost exclusively and really helped as signals faded in and out of the noise floor.

This station has three small towers on a city lot so we've been fighting inter-band RFI for years. The antennas are just too close for serious multi-op, even SO2R, operations at high power. On the low bands, the Beverage array is 800' from the transmitting towers on another property. This virtually eliminates the RFI problem on the low bands. But with the 40 and 20 Yagis on the same mast, 20 meters is rendered nearly useless when 40 is transmitting, especially doing RTTY on the low end of 40 which puts the harmonic right in the middle of 20 meter RTTY action. Our main objective in the week prior to the contest was to solve the high-band RFI problem. We brought a 12AVQ vertical to put out at the Beverage feedpoint for an RX antenna on the high bands. Ultimately, it was never used ...

As one step in our RFI troubleshooting, we found that using the C31 on a separate tower from the 40 enabled us to coexist on those two bands. In parallel, the 10 and 15 Yagis share the same boom and had similarly intolerable RFI between those two bands. Again, using the C31 for either 10 or 15 nearly eliminated that problem. So, one alternative that emerged was to use the C31, but it had to be shared between 10 and 20. We didn't want to restrict ourselves to choosing between those two bands however. The solution came to us indirectly in the form of a newly designed high-power triplexer build by K2NG for his PJ4 contest station over in Bonaire.

Roger, N4RR, used this trip to swing through Bonaire to deliver the triplexer to that station. In return, K2NG agreed to let us "burn-in" the new triplexer at P49X. Initially, this was a low priority in my mind because I didn't see the utility of band-sharing the C31 as being worth the additional complexity of not only the triplexer but also the three StackMatches to allow 10, 15 and 20 to simultaneously use the C31 with their monoband Yagis. Instead, we used the triplexer to solve our RFI issue by simply sharing the C31 between 10 and 20 at the same time. The 10 and 20 meter Yagis were not used. There was some constraint by not having seperately rotatable antennas on these two bands, but it turned out not to be a problem. Antennas here are pointed north most of the contest anyway.

The net result was that the high-power triplexer worked flawlessly. We found no RFI contributed by it and it worked magically all weekend at full legal-limit RTTY. In my mind, this is a must-have addition to the station here so that the C31 can be fully deployed, not only for RFI relief but also as a second antenna that can be phased or selected with the monobanders for the three high bands. In fact, it might make sense to replace the 10/15 duo-band Yagi with another tribander and deploy two triplexers with three StackMatches. This should finally allow us to do SO2R, MS and M2 from this modest station. Multi-multi, though, is still hard to imagine!

Thanks to all the other participants who played the game with us! An amazing number (yet to be counted) worked us on all five bands. And, thanks to station owners P40L (W6LD) and P49Y (AE6Y) for supporting our "RTTY thing" here in lovely Aruba.


Ed, P49X (W0YK), Glenn - W6OTC, Steve - K6AW, Roger - N4RR