| Author |
Message |
    
Jimmyhoffa
New member
Username: Jimmyhoffa
Post Number: 1
Registered: 1-2021
| | Posted on Wednesday, December 29, 2021 - 10:50 pm: | 
|
I installed a Maco m103c on my rohn 34' push up pipe.. swrs are 1.1... i have lost audio on 4 radios and 2 amps since.. ive ohm'd all my coax which is MTD LMR400, and my jumpers are From alpha, 3ft with amphenol ends...my radios were first one down was my Anytone at-6666 popped a final.. figured nature of the beast from what ive read.. next was my Cobra 200 gtl Dx.. talking local on sbb... working fine one minute ... no carrier the next..but can hear audio in a close by radio.. then was my Excalibur SSB.. again trying to talk a little distance on 38 LSB.. all was fine then bam... no carrier... audio tho.. only thing the same in all these situations was my PDC-700 meters.. they've always acted a little weird checking swr...but i also checked with 3 other meters and seem ok... oh other radio was my stonewall jackson.. it was the first one that did it ..but that was with the new coax and my sigma venom 5/8... but same meters...im at a loss for words... i ordered new meters...the beams only been up 3 weeks!..thinking about taking it down and crushing it along with the PDCs like aluminum cans...i talked to a antenna builder down south..he swears its the LMR400... but i read daily that others use it with out problems..i ordered rg213u to replace it with...the connection at the beam hasn't been sealed yet, cause wanted to make sure i didn't have to do any tweaking on swrs, but havent had any real weather to be concerned with yet....HELP |
Ke0koy
Junior Member
Username: Ke0koy
Post Number: 46
Registered: 12-2018
| | Posted on Thursday, December 30, 2021 - 2:06 pm: |
|
There is nothing wrong with LMR-400 coax. Do you keep the meter in line the entire time or just to tune up? Is it possible that the meter has a faulty component that only arcs over during the peaks? It is possible that it works fine on dead key tune-ups/SWR checks but shorts out on the peaks. If it does short/arc over, the needle isn't going to show you. I would put another SWR meter in front of it, give it a short blast of increasing power until you reach the max and find out if the that is the case. |
Jimmyhoffa
New member
Username: Jimmyhoffa
Post Number: 2
Registered: 1-2021
| | Posted on Thursday, December 30, 2021 - 8:47 pm: |
|
I have a new meter coming.. that's the only common denominator I can come up with... When the Excalibur SSB went I was looking at my meter .. it usually swings about 30w and all the sudden it was doing 45+ and wham . No power, if I was on am no carrier, I also tried FM and CW.. nothing.. but radios all produce enough audio to come across a radio close by . Very close |
Ke0koy
Junior Member
Username: Ke0koy
Post Number: 47
Registered: 12-2018
| | Posted on Friday, December 31, 2021 - 6:30 pm: |
|
The reason the radios are still being received by nearby radios is because the driver is still functional, only the final blew. The radio is still creating a modulated carrier, merely at a few tens to hundreds of milliwatts and not directly connected to the antenna jack. If you attempt to swap the final on these radios, do yourself a favor and swap the AM regulator while you are in there. Often times that level of abuse will heat those up to the point their life expectancy is questionable, and they are dirt cheap. |
Jimmyhoffa
New member
Username: Jimmyhoffa
Post Number: 3
Registered: 1-2021
| | Posted on Tuesday, January 04, 2022 - 10:10 pm: |
|
Awesome thank you! |
