Beam Steering in Combat or How to Use Software Radio and an Array of Short Verticals in the 2008 CQ 160 Meter Contest The 2008 CQ World Wide 160 Meter Contest started with the discovery of S5 power line noise on the S and SE (150 degree) Beverages. Fortunately, the noise was not particularly audible in any of the other directions. But the noise affected the phased array receiving system. While dropping my child at her grandparents for the weekend, I drove past some utility work that was taking place about a mile from my QTH. I tuned the car radio to a relatively empty frequency (1630 kHz, SWACO Radio, all trash, all the time). The noise started rising as I approached the work area and peaked adjacent to a pole with temporary rigging. Since the contest started in only an hour, I didn't think there was any opportunity to affect the situation (like crashing the car into the pole). During the contest, I intended to test the refinements I recently added to the Steerable Phased Array receiving system ("phased array" for short). See k1lt.com for prior soapboxes about the development of this system. Since the Stew Perry test, I improved the sensitivity by replacing the op-amps in the "front-ends" with lower noise devices, decreased the latency by numerous computer configuration changes (process and interrupt priority, etc.), and added a headphone audio switch box to conveniently route audio (no more mousing). I tried to add automatic IQ balancing, but that still doesn't work correctly. During the CQ 160, I did not notice any interference from image signals, even though contest activity spans both halves of the 96 kHz of spectrum the SDR presents. (I set the center frequency to 1855 kHz, which means signals above 1855 might image into the range below 1855.) The configuration that seems to work most conveniently is to use the Beverages and main radio for the anticipated "most difficult" direction (usually east toward Europe) and use the steerable system for western directions. Then, when running, I can listen in two directions simultameously, and usually all callers are audible. The problem is that a caller from the west who is off frequency requires that I grab the mouse and tweak the SDR passband, while a caller from the east who is off frequency requires that I mess with the RIT control on the main radio. Although this receiving setup requires more manual effort, I don't miss callers who happen to be coming from the wrong direction. The first night, conditions were good. However, the power line noise that affected the S and SE Beverages also wiped out all but NE and SW on the phased array. So, I tried to use the phased array for Europe, and the Beverages for other directions while operating 2-receiver mode. However, the lack of the equivalent of RIT on the SDR receiver made it difficult to use tuning as a signal discovery process. After a while, I reverted to traditional single radio operation. Sometime after sunrise Saturday morning, the noise went away. The second night, I thought conditions were better, perhaps even superb. I was able to run Europeans during my sunset, and again during their sunrise. Greg, NZ8R, came over Saturday evening. He deferred to my experience with 160 DX contesting during European sunrise, but he did take the controls during the 0800-1100Z slow time while I napped. Then, being of sound mind in the sunrise time frame, I was able to run JAs for the second time ever, if you can call 5 JAs a run. (The first time was a run of 2 JAs, last year). While I was napping, Greg insists that he worked RV6CC at 1013Z, which seems unlikely to me. However, I can't figure out any way a mis-copy would result in that callsign. For now, the contact remains in my log, although I might delete it before submitting the log to the CQ scoring committee. We need a way of marking questionable contacts so that the scoring committee can either delete or award them without a penalty, or at least use them for credit for the other station. Greg liked the phased array second receiver as well. He would like to see a mechanism of setting the transmitter frequency via SDR-Shell. That would make the steerable receiving system into an excellent spotting and multiplier hunt radio. Of course, he doesn't know that the SDR guys intend for their software to work as a transceiver with the approriate converter and power amplifier. The array performance seems to have reached a level where other factors that accompany the SDR receiving system become significant. For example, SDR-Shell needs an "incremental tuning" control, so that the receive frequency can temporarily be adjusted for a caller that is off frequency. Also, the filters built into SDR-core are not as sharp as the filters in my IC765. That is, the filter skirts are wider, even though the filter can otherwise be made very narrow (down to 10 Hz). Theoretically, an 8 element broadside/end-fire combination (about 15 db peak to average directivity) should significantly out-perform my Beverages (around 12 db directivity at best), but I still don't hear it. Sometimes, the array can beat the Beverages, and sometimes it can't. The phased array continues to improve, but I'm not ready to start rolling up my Beverages. Besides, one can never have too many receive antennas (switching and searching not-withstanding). Breakdown summary: UTC 160 rate total 00Z 80 80 80 01Z 87 87 167 02Z 94 94 261 03Z 63 63 324 04Z 46 46 370 05Z 45 45 415 06Z 74 74 489 07Z 53 53 542 08Z 27 27 569 09Z 12 12 581 10Z 0 0 581 11Z 46 46 627 12Z 33 33 660 13Z 0 0 660 14Z 0 0 660 15Z 0 0 660 16Z 2 2 662 17Z 0 0 662 18Z 12 12 674 19Z 21 21 695 20Z 32 32 727 21Z 44 44 771 22Z 45 45 816 23Z 21 21 837 00Z 38 38 875 01Z 61 61 936 02Z 23 23 959 03Z 65 65 1024 04Z 40 40 1064 05Z 28 28 1092 06Z 29 29 1121 07Z 19 19 1140 08Z 16 16 1156 09Z 12 12 1168 10Z 10 10 1178 11Z 22 22 1200 12Z 22 22 1222 13Z 16 16 1238 14Z 21 21 1259 15Z 6 6 1265 16Z 0 0 1265 17Z 0 0 1265 18Z 0 0 1265 19Z 12 12 1277 20Z 18 18 1295 21Z 19 19 1314 22Z 11 11 1325 23Z 25 25 1350 2 point QSOs: 1057 5 point QSOs: 101 10 point QSOs: 192 DX: 4O, 5B, (5) 9A, (2) C6, CE, CN, CT, CT3, (2) CU, (2) CX, (40) DL, (2) E7, (7) EA, EA6, EA8, (3) EI, EL, ER, ES, (2) F, (8) G, GD, (2) GM, GW, (8) HA, HB, (2) HK, HP, HR, (5) I, (5) JA, KH6, (2) KP2, KP4, (3) LA, LX, (4) LY, (2) OE, (5) OH, OH0, (18) OK, (6) OM, (3) ON, OZ, P4, (7) PA, PY, (13) S5, SM, (6) SP, (2) SV, TF, TI, (4) UA, (2) UA2, (5) UR, V3, VP9, (3) XE, (2) YL, (2) YO, (3) YU, YV, and ZF