Carrying on from the initial testing I did last week, I went out for a bike ride yesterday and took my experimental vertical along. (I gave a general description of this antenna project in my previous post.) I rode a few miles up the Schuylkill River Trail and on to a park along the Perkiomen Trail.
I set up in a remote section of the picnic area and quickly took some readings on 40 and 30 meters with my antenna analyzer. I had done some tweaking to the loading coil but, unfortunately, both bands were still resonating too low.
I set up my KX3, intending to make some contacts. This, however, was not to be. There was a background noise level that was higher than I had encountered on a previous visit to this park. As I was tuning around, I looked over and saw that the wind had blown my antenna over. I neglected to bring anything along that I could use to stabilize the antenna and tripod. I set it back up but it wasn’t long before the antenna was on the ground again. After it blew over a 3rd time, I gave up. I packed up the bike and rode back down the trail to my truck.
This morning I made another adjustment to the antenna’s loading coil and headed over to Valley Forge Park to test it. Like yesterday, it was somewhat breezy. This time, I hung my backpack from a hook on the bottom of the tripod to make sure the antenna stayed upright.
I took some antenna analyzer readings and found that the 40-meter band was now resonating right where I wanted it. I saw some improvement on 30 meters but it was still resonating below the band. Obviously, the tap for the 30-meter band is in the wrong place.
As I tuned around, it the bands seemed better this morning. I worked N5P in Texas on 20 meters. N5P was participating in the Museum Ships Weekend event from the National Museum of the Pacific War. I moved down to 30 meters and heard a couple of strong stations. I didn’t make any contacts there, though.
I called CQ on 40 meters and quickly got a call from N1PVP in Massachusetts. I remembered working Marino a couple of weeks ago. He always has a very strong signal into Pennsylvania. I wrapped up with a two-way QRP QSO with Alan AC8AP in Ohio.
Antenna-wise, I have to do some thinking about how to proceed with my experimental vertical. As I see it, I have a few options:
- I could continue to tweak the existing coil. If I remove turns from the bottom of the coil while adding the same number of turns to the top of the coil, this would effectively move the tap point for the 30-meter band.
- It might be easier to just re-wind the coil and add a few more tap points. I could do some testing to see which tap works the best.
- I could always invoke the “do nothing” option. The SWR on 30 meters is only about 4.3:1, which is a trivial match for the KX3’s internal tuner.
In any event, the antenna is useful as it stands. I’ll take some time this week to consider my next move.
72, Craig WB3GCK
WB3GCK QRP Amateur Radio 