01/03/2010 | TF3DX/M Having recently improved my mobile antenna and built a new tuner for the car, I thought that driving down to the west coast of town to see if I could land a few transatlantic QSOs in the ARRL 160 m
contest might be worth a try. Perhaps getting a reply from JA7FUJ to a CQ, resulting in a 569/559 QSO while testing the new mobile set up on 160 m CW a couple of weeks earlier, had twisted my brain! Anyway, I ended up sitting in my car for almost 8 hours harvesting 27 QSOs in log, one of which seems to be a typing error on my behalf or a dupe.

Admittedly, a QSO rate of 3.5 QSOs/hr is low on any account, but still it was much more than I actually hoped for. Bear in mind that TF is inconveniently located under the aurora oval, and the low
efficiency of short whip antennas on the lower bands. Mine is longer than most, 1.5 m leg under a 3 inch diameter airdux coil, topped by a 3.3 m whip. The most important parameter to measure and maximize in installation like this, is of course the antenna RF current. That I learned from the ARRL literature half a century ago, and the fact that it was soon swept to the side for the more fashionable SWR measurement did not diminish its value. SWR tells nothing about efficiency, and I think it is about time that we herald the thermocouple ammeter again! From the antenna current and dimensions, I now calculate the radiated power to have been around 2.5 W with my 100 W FT-900. I believe that 2.5% efficiency is pretty good for a mobile whip on 160 m, more like many an 80 m mobile antenna is sporting.

With such a small signal I assumed that calling CQ TEST would be in vain, I would not be able to keep a frequency clean. Thus I took the time to tune between available NA stations, waiting until I deemed them strong enough to warrant a call. I tried to ride on the wave of the slow but perpetual QSB by calling on the upswing, but waiting if a strong Eu station was giving me competition. Using this strategy I
usually stirred a response soon if not at once, many coming back with a '?' or a part of my call at first. Only few QSOs took a real persistence to complete, and some went right through on first call. I had feared that the trailing /M would give me trouble, but fact is that most jumped on it right away. Quite a few came back the first time with '/M?' indicating that the surprise element was giving me an edge. A few stations commented approvingly.

The condition never seemed to be really good here; I worked an assortment of the northeastern states, K9DX in Illinois was probably the best DX. In fact I worked most I heard, stations further west that these were working were almost universally nil here. Canada, which often has better signals here than the US, was poor; I only got 3 of them. -- TF3DX