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
Rafael,
While not the exact same antenna, I had an SWR problem on an M2 antenna (7 elements vertical yagi) once that drove me nuts until I figured out the problem. This may help you (or others down the road...) The observation was the SWR was high (sometimes it was intermittent, but mostly it was high). The culprit? It was a poor electrical connection between the driven element and the boom! There was "gunk" or corrosion of a type under the aluminum "block" of the driven element that is screwed to the main boom via the stainless steel screw. Using a scratchy Scotchbrite pad on both the block and the main boom, I was able to clean it up and fix the SWR issue.
It took me months to determine the cause--I replaced the coax from antenna to preamp, the preamp itself, swapped coax feedlines; I opened up the original driven element, just SURE there had to be a break in the internal wire(s). Nope! I eventually bought another new antenna just like it to swap out the driven element, and finally then did I see what was the apparent cause.
It's a case of having to see it myself, to believe it...
Rafael, if I was you, I'd at least check the connection of both driven elements to the boom---clean it up well, and see if that fixes it. If not, no harm done...but this is a place that would NEVER have occurred to me previously...
Please let us know what fixes your issue!
73,
On Mon, Jun 17, 2019 at 1:09 PM Rafael Pena via AMSAT-BB amsat-bb@amsat.org wrote:
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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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@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
participants (2)
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Mark L. Hammond -
Rafael Pena