Many thanks to John (N3AAZ), who shares the following notes from a recent antenna project:

Hi Thomas

For what it’s worth, here’s an easy, cheap, very lightweight, multi-band, no counterpoise antenna for portable ops.

This build took place on a rainy day at a campground in an 18ft RV and was inspired by an article written by Craig (WB3GCK): No Counterpoise Speaker Wire Antenna.

This antenna can be set up as an inverted V or inverted L.

I cut a 30/20 ft version to hang on a 32ft Jackite telescoping fiberglass mast. I read that several ‘random’ lengths, the 50/25 and 25/17, have also been successful.

Cut a 30 ft length of speaker wire (do not peel or separate it yet), then measured back 10 ft and peel off then cut only one side of the speaker wire twin lead. This will effectively create a 30-foot antenna with a 20-foot “balanced” feed.

You will then need a “BALUN” with unbalanced input and balanced output.

My 1:4 and 1:9 did not work because both ports are single-end BCN connectors soldered on a PCB.

Luckily, I also pack an MFJ 9211 (1:4 QRPocket Current Balun).

Using a NanoVNA and MFJ-902.mod.aaz (mod to form an L-network–more info on my qrz.com page) I measured less than 2:1 SWR on 40, 30, 20, and 15 meters.

The N7DDC ATU-100 reports…

• • 1.18 :1 SWR on 15M
  • 1.03 on 20M
  • 1.16 on 30M
  • 1.88 0n 40M

It loads well.

My first 20-meter contact was a POTA contact with W4TTU (approximately 700 miles away), who gave me a 559 at 5W–he was 579 and signed “72,” so I assumed running QRP as well.

Not too shabby for an impromptu rainy day project hi hi!

72
John
N3AAZ

Thanks for sharing these notes, John! This looks like a fun little antenna build.