[amsat-bb] M2 Leopack 2Meter swr

Rafael Pena pinoleronica at hotmail.com
Thu Jun 20 13:32:42 UTC 2019

Fellow sat enthusiasts, I was able to find out the issue with high SWR on 2M M2 Leopak.   It was a user error.....the culprit Coax or barrel F/F connector (still to check).

Prior to finding out the issue, I did remove the special rubber tape from each of the cable connections....clean them...test continuity passed.  The only change in my setup, I moved my station from 2nd floor to basement, hence the need to add more coax to both 2m/70cm.  I used a F/F N barrel on each coax run and seal them with Dual Wall Adhesive Lined Heat Shrink Tubing.

I had mentioned that I did a check right at the antenna feed-point with a small coax jumper...well, this jumper cable had issues also.

Yesterday, I removed both 2m/70cm from the roof and brought down to basement for a closer checkup (too hot to be on roof).   I used a different jumper coax cable and run test with analyzer attached.  Perfect match all across 2m.   So I did not try anything else and placed them back on roof.   Run the same test with small coax...perfect!   This time I swapped the coax and run the same test from the station...perfect!   Now 70cm is experiencing high SWR.

So I now need to cure this coax by removing heat shrink tubing, barrel removal, etc....test with analyzer.

This is a lesson learn that I hope can be of some use for others....and please accept my apologies for the bandwidth....

See you on sats soon!

Rafael / NN3RP

De: Rafael Pena
Enviado: lunes, 17 de junio de 2019 01:03 p. m.
Para: amsat-bb at amsat.org
Asunto: M2 Leopack 2Meter swr

Recently, I had my roof done and had to remove the M2 Leopack from the mast together with the G-5500 Az/El.   I sat it on the roof floor next to my house.   Now that I place it back, the 2M SWR is way high off the sat or regular 2m frequencies 440 is as expected.

It is not coax since I tested it with a short piece and analyzer with same results.   I had not check the coax stubs yet and thought to write hear first.   Any hints will be appreciated.

M2 website has a "Blog" which contains only info on Ohm meter testing.

Rafael / NN3RP

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