[amsat-bb] M2 LEOpack tuning

Andrew Glasbrenner glasbrenner at mindspring.com
Sun Apr 5 16:21:00 UTC 2020

Hi Mark,

Experience with these antennas at the demo station at Dayton, confirmed by Robert with M2 who fixed the issue, suggests that you may want to look at the routing and placement of the phasing cables. They are very sensitive on placement, and the issues we had were fixed by Robert rerouting them to be identical with the diagrams in the instructions. Good luck.

73, Drew KO4MA

-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of Mark D. Johns via AMSAT-BB
Sent: Sunday, April 05, 2020 8:58 AM
To: AMSAT <amsat-bb at amsat.org>
Subject: [amsat-bb] M2 LEOpack tuning

I’ve had my LEOpack antennas about 8 years, but over the winter my station became almost totally deaf on 2 meters. I took the 2 meter beam down and cleaned up a bunch of corrosion around the coax connector, and that seems to have helped the situation, but...

I checked the antenna with my MFJ Antenna Analyzer (which I did not have back when I first assembled these antennas) and find that the 2 meter beam is resonant at about 143.95 MHz — just below the 2 meter ham band. Up at 145.9, where I would LIKE it to be resonant, my SWR is about 2.5:1. Pretty high.

Messing with the tuning sliders only made things worse (these adjust impedance and not necessarily resonance), so I’m wondering, has anyone else found it necessary to trim the elements on these?

My calculations are that about 1/8” off each end of the DEs would bring it up the 2 MHz needed. Opinions?
***Sent from Gmail on iPhone***
Mark D. Johns, Ph.D. K0JM
Professor Emeritus of Communication Studies at Luther College, Decorah, Iowa USA Now residing in Minneapolis, Minn.
"Get the facts first. You can distort them later."
---Mark Twain
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