Tuning the Counterpoise

My antenna wires at the house were getting moved around a bit with some projects. I found my SWR was a bit high on a certain HF band, and I found moving or coiling the counterpoise (~5.2M) to shorten it greatly reduced SWR. I have to remember to watch performance and adjust the counterpoise as part of my setup and operating.

POTA Antenna Test 3

I compared the 20m EFHW with the 12.5m EFRW at Sam Lewis (US-1418). I threw really high and made both antennas nearly vertical into high trees, not inverted-v.

EFHW could hear pretty well, and the SWR sweep showed again that I could shorten it, so I did lower it and take off a few cm.

The EFHW didn’t seem to like its counterpoise. With the counterpoise, it was giving me an SWR of 2-2.5:1 on 40m when I transmitted. If I removed the counterpoise or kept it coiled up, the SWR was lower. I still made most my contacts on 40m.

I think the radio may have again been interfering with the mouse when transmitting. I already had chokes on both ends of the feed line, but adding the counterpoise helped that common mode interference. It was a rough day.

The EFRW would not tune well at all on 40m with or without its single counterpoise. That surprised me greatly, because I had tested that same unun with my existing EFRW antenna out the front window at home.

I wonder if it had something to do with each antenna being mostly vertical. I wonder if they needed more radials instead of a single counterpoise. K4OGO (Walt of Coastal Waves and Wires) always adds so many radials to his verticals.

This had me questioning everything. I thought I was doing something really good by getting the wires high and vertical. When I brought the radio home and connected to the same old EFRW, it was again performing normally.

I also learned that the POTA website cuts off your activation and starts a new one at 00:00UTC, 8pm, so I ended up with 2 QSOs counting toward a second (incomplete) activation at the park.

pota  efrw  antenna  efhw 

New 21.56m EFRW

I assembled a new 71-ft (21.56m) EFRW and strung it up at Emily’s. It’s 5-6ft off the ground. I give it a 17-ft (5.2m) counterpoise and a 9:1 unun as usual. 2:30pm EST, 1W into it gets me midwest to a little bit of Europe on 10m. I’m not making many contacts, so I bumped up to 5W.

The antenna tunes on 40m too just fine. I’m getting a few more contacts there.

As a new strategy, I’m aiming for ALC around 1.0, instead of just below any movement. This allows me to not touch the power slider in WSJT-X quite so much.

antenna  dx  efrw 

Power Supply Noise

Running the 41-foot (12.5m) random wire, it works great for 10m and 20m. It tunes really quickly. The power supply gives lots of buzzing and noise on these bands. ATT tames the power supply noise pretty well.