My first single band contest on 160m. Expectations were not easy to define and not too high.
Until now, I only worked 50 DXCC, most of them with an inverted L antenna and with high qrm.
Goal : if possible 500 Q with at least 50 DXCC (and hope on some new ones) and without technical problems.
Using the windom antenna I hoped to perform better on receiving but I was a bit afraid of the high angle of the antenna, which is only 15m above ground.
Preparations as usual, last minute. I measured the antenna on Wednesday and the resonance point was at 1740 Khz. 100Khz to low, so the antenna was too long. I calculated the length and fold back the both endings, keeping the windom 1/3 versus 2/3 factor in mind.
Now the dip was on 1790 Khz, not what I calculated, but I had not the time to do more fixing. I forgot to torsion the wire. Just fold it back with some tape. I found out that the swr was swinging between 1.4 and 2 on 1835 Khz.
I decided to start the contest with the OMpower ampli, because this one can suffer more reflected power. Goal was to use 1000 W, if possible 1300 W.
After a few seconds, the first failure occurred, too much reflected power. I found no other solution than to continue with 500W. At 4h UTC I stopped after 200 Q’s, all S&P, because I needed some sleep to perform well on my streetrunning competition on Saterday afternoon.
On Saterday morning, the weather was very rainy. I measured my swr and this time resonance occurred on 2200 Khz !!!
I suspect ground increased capacity as the root cause of this move. Back into the garden, undo the folding on both sides and measure again. SWR stayed too high on the contest frequencies.
Plan B : place my good old manual MFJ tuner in between antenna and ampli and run with the Acom1000. I achieved 750W without sparks. This was a good choice. I could make my 500Q within a few hours, and achieved 64 countries. On Sunday morning I stopped the contest, to have some family time.
- There is no benefit on 160m using FT8 200W for new countries. With 750 W in CW I can make QSO with the Carribean area, strictly needed for DXCC.
- The evolution in assisted mode is very much expanded by adding skimming features into the cluster. I suspect some USA stations could “hear” me thanks to this information.
- On receiving side, my antenna performed very well. Much less noise compared to the vertical
- Weakest point was Asia and Middle East. On 80m, working Carribean means also working JA and YB. On 160m this was not the case.
- The windom antenna @15m performs very well and is stable on all bands, except for 160m. Here the ground behavior has a huge impact on the resonance point.