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 

985 Workbench Net - 2024-05-13

My Week in Radio

  • I purchased some power cables that split out the 12V line out of USB-C, so I can power my radio from a USB-C power brick/jump-starter battery.
  • Marie and I relaunched my EFRW even higher into the the tree in the front yard. I used the slingshot out the second-story window, while Marie watched that the street and sidewalk were clear.
  • I did the RTTY test and FT4 sprint last Thursday.
  • I saw some better propagation on FT8 before the weekend’s solar storm: Ukraine, Northern Ireland, and Greenland at the arctic circle.
  • While the bands were dead over the weekend, I built a couple new, lighter antennas for POTA. I cut and tuned some 20m-long EFHW wires and tuned them with NanoVNA. I used recycled plastic gum boxes as enclosures and winders for the un-uns and wires. I also 3d-printed a winder that holds the transformer and heavier speaker wire. I’ll test the antennas when bands are obviously better. I’ve not really used an EFHW much, so I’m curious to see how it performs compared to EFRW.
  • I saw some recovery today in the band today: Panama, Canary Islands, and the Cayman Islands.
  • Ron, WA3VEE, sent photos from the Antique Radio Meet in Kutztown.

My Question for the Night

What are the effects of solar cycle and solar activity on propagation? We’re in a high point of the solar cycle, so 10m is good, but too much and it blacks out propagation?


  • Vic, KC3TYX, made a VARA-C contact.
  • Jim, KC3RFG, found an OCF dipole to be quieter than end-fed.
  • Jim, AF3Z, has trouble with his Ten-Tec radio sometimes not transmitting.
  • Jeff, W3JAM, wondered if anyone was making 6m contacts over solar storm.
  • Mike, W3MFB, noted that 17m sometimes is a pipeline right into Florida in afternoon/evening.
  • Tim, W3QP, is headed on SOTA campout.
  • Jack, K3YVQ, Is it OK to use GMRS on a radio that does ham freqs and more?
    • Mike, W3MFB: technically, the radio should be locked to gmrs frequencies.
    • on the air, no one would know, though.
    • Ron, WA3VEE: FCC approves radios for particular services.
    • GMRS radios are “type-acceptance”, and the right power limits.
    • Some other radios might be hard to limit to the right power.
  • John, KC3WWC: What’s the solar storm do to propagation? Some activity is OK, but too much is bad?
    • Chuck, NA3CW:
      • RF is produced by accelerating (“wiggling”) electrons.
      • Ionosphere doesn’t “bounce” signals, but instead “receives” and “retransmits”.
      • We have loose electrons in the upper atmosphere, good for retransmit.
      • Solar storm ionizes the atmosphere at different levels with varying intensity.
      • Our RF hits ions in lower part of the atmosphere and gets slowed, absorbed (D layer).
      • LF is affected the most, since it moves the electrons further.
      • Solar minimum offers less ionization at any level.
      • D layer, E Layer, F1 layer, F2 layer.
      • Better shortwave propagation at night.
      • Lots more is understood now about the ionosphere.
      • Frequencies are coordinated in SW to adapt to seasonal changes.
      • Electrons free in thicker air recombine more easily, so don’t pass RF.
      • Winter: great distances, because air is thinner.
    • Tim, W3QP: noise also comes up during storm and masks signal.
    • This video from Coastal Waves and Wires explains the effect a bit.

New Wires

The bands were dead with the terrible geomagnetic storm this weekend, so HF is very limited. I was only able to contact Lititz from Mountville.

With the downtime, I built some new EFHW antennas. I tied some wires to trees, stretched them out, and tuned each of the 2 20m EFHW antennas with the NanoVNA: one speaker wire, and the other lightweight silicone wire. I built new ununs and mounted them in plastic gum cases and a 3D-printed winder.

I also cut a lightweight EFRW, 12.5m, from the silicone wire and gave it a gum case as a winder.

I’ll test the new antennas soon when the bands are better.

Backyard Alternate Antenna

I cleaned up the backyard a bit, and ran a new 12.5m (41ft) random wire up the hill behind the house.

My first tests the next day on 30m at 1W got me some contacts. By 4:40pm EDT, the bands were all in “poor” condition, so it got tough to test.

The next morning, I watched the 40m band close. It was ablaze at 8am, but getting pretty quiet by 10:30am EDT.

I compared the old antenna out the front with the new antenna out the back using FT8 and PSKReporter.

The back antenna saw fewer decodes on 15m on average. It mostly lacked any stations from Europe. Looking at the antenna’s physical attributes, it starts on first floor (lower than the old antenna) in backyard, but it slopes up more vertically. The middle of the antenna, on average, is blocked by the hill to the East.

The old antenna out the front saw more decodes overall, including Europe. It starts at second floor window and only slightly angles up. The whole antenna is higher and clears the hill, even though Europe may still be mostly all the end of the antenna. It performs better.

I had fun physically launching the new antenna, but I’ll need to do some more work to get more of it higher in the air to be useful.

hf  antenna  ft8 

985 Workbench - 2024-04-29

My Week in Ham Radio

  • Built and deployed a 1/4 wave ground plane with radials
    • wire soldered to an UHF chassis plug
    • fed from the bottom
    • hung in a tree by cord
  • York Hamfest and 2 parks out that way
    • Codorus
    • Sam Lewis
    • EFRW
    • Mostly ft8
    • 40m hot at 5:30pm
    • 2 phone contacts in Canadian parks for park-to-park QSO
    • Took some time to experiment a little
    • Fishing pole mast with 3D-printed fork on the end to catch the wire
    • Stop pulling on coax…loosened ends
  • SPDX RTTY contest (Poland)
    • 2 contacts
    • ended at noon UTC on sunday, so ran out of time
  • AubsUK firmware for Quansheng
    • 10 scanlists
    • automatic scan on power-up, feature request
  • Picked up a new podcast: Ham Radio Workbench
  • Simplex Net: heard 16 of the 38 people

My Questions

  • with nicer weather and time to experiment with antennas, how would you recommend iterating and experimenting? I have:
    • the QRP transceiver
    • digital modes & pskreporter
    • nanovna
    • some modeling software I could learn
    • the latest ARRL Antenna Book


  • Dipoles, sloped or flat?
    • Flat leaves nulls toward the ends
    • Sloped fills it in to be a bit more omnidirectional
    • An antenna close to the ground is going to be NVIS
    • Vertical is omnidirectional
  • Ron’s seeing infinite SWR on the “screwdriver” antenna.
    • Others have had problems as well.
  • Mike wonders about viability of using 6m FM in his area
  • My Question: How should I evaluate and structure my experiments with antennas?
    • Conditions change constantly
    • Learn to read solar data
    • Take notes on conditions and try to test in similar conditions
    • Vic’s experiments:
      • endfeds
      • hamsticks
      • radials
      • aluminum screen or faraday cloth for ground plane
    • WSPRnet and pskreporter help gauge how you’re getting out
    • See what you can hear
    • Qualify callsign for different tests, so I can tell them apart in pskreporter: kc3wwc/a, kc3wwc/b, etc
  • Ken wonders about TNC for packet radio on HF/VHF
    • Glenn, N3MEL would be the person to contact
  • We heard lots of interference and doubling in the beginning of the net
    • This was likely another manifestation of intermod
    • Tropospheric ducting happens more in morning in the summer

Quarter-Wave Ground Plane 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.

antenna  2m 

Ridley Creek POTA

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]

Eclipse 2024

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.

FM Bandstop Filter

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]

VHF Reception

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?