Antenna

I followed calculations and instructions to build a quarter-wave ground plane antenna from some wire and a UHF connector that I picked up at the last Ham Fest in Harrisburg. I cut everything a little long and soldered it together. I trimmed the radials to about 54-inches and folded and rolled the radiator wire to a length that is resonant at 147MHz. I measured with the NanoVNA. Once it was at the right frequency, I found that bending the radials up and down could adjust the SWR at its lowest point on the graph. Keeping the radials slightly flatter had a lower SWR than the 45 degrees suggested in the original design.

This ground plane antenna feeds from the bottom, which is physically more sound than the vertical dipole I had up previously. I tested it last night when I strung it up, and it reaches Harrisburg and Parkesburg with no problem.

We had some time in West Chester to visit Ben and see the new Mini Countryman, so I stopped by Ridley Creek State Park to activate. I had lots of tangles trying to toss my 21.56m EFRW into a tree – it took 30 minutes just to get started, but I had the wire at least 25 feet into the air. I operated FT8 and FT4 on 10m from a pavilion. [Read More]

Matt and I ran to Erie, PA to watch the eclipse, and activated US-1402, Presque Isle State Park before eclipse. 10m was a bit slow, but I got there on FT8. I ran my 71-foot (21.65m) EFRW sloped up into a nearby tree from our station on a picnic table.

I got some audible screaming on the speaker in addition to the normal clicking when I hit the tuner. I usually have a choke near the radio, and that was missing.

It was cloudy and even some rain in the morning, but it cleared and we saw some blue sky before the eclipse started around 2pm.

Totality was at 3:16pm EDT. I have a video in 360 degrees.

I posted to Facebook and got lots of discussion about the FM bandstop filter. When I started adding better external antennas, I could reach further (tx and rx**, but I also found that some VHF frequencies got much worse. It turned out I was overloading the receiver with the strong FM broadcasts in my area and increased sensitivity of the better antenna. I found a bandstop filter helped bring back those signals I was losing. [Read More]

Reception Problems

During 985 net on Monday night, which is VHF on my UV-K5 running egzumer 0.22.0, I’d get periodic static in reception. It got bad enough to completely cut-out. I was using my simple wire dipole hanging in the tree outside.

K3IR had been frustratingly quiet as well, so I checked the antenna with the NanoVNA as it hung outside. There were no fluctuations in SWR, so it’s not connections or proximity.

I tried the Explorer QRZ-1 HT, and it sounded great on the same antenna on the same net. Is my UV-K5 broken?

To test a bit further, I ordered a new UV-K6 to compare. I also downgraded to egzumer 0.21.0 for further testing.

The next day, Tuesday morning, K3IR was sounding better, but I was getting the same periodic noises. The outside antenna doesn’t completely cut out, but shows terrible doubling/overload as if from FM station.

Inside, the magmount antenna on the 3d printer is better. Is the dipole outside too sensitive and bringing in more signal than the frontend of the UV-K5 can handle?

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.

I bought a project J-Pole made of 450-ohm ladder line at the Hamfest for a couple dollars. I rebuilt the connections, firmed up broken parts with some wood splints and tape, and tuned it with the NanoVNA.

It seems to be working pretty nicely for 2m and 70cm. I’m pulling in stronger signals, and still able to transmit.

I have a dipole that’s 20m long (10m each side) strung through the house right to the banana plug adapter to the radio and no coax. I’ve coiled the wires together at the feed point to shorten and tune. I can run 40m with tuner turned off. I’m hitting Europe, Central America, Canada, and the midwest US.

I figure, since the wires are insulated and kept parallel to each other, the coil is serving as feed line and not part of the antenna.

Antenna of the day: 12.5m random wire w/ 9:1 unun strung from high in loft to the outside laundry line. It tunes for 10m, 12m, 15m, and 20m nicely, but not for 40m. I switched to 5m dipole twist for 40m.