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MFJ Meter Diodes Upgrade?

FlatlandBusa

Well-Known Member
Nov 20, 2022
224
390
73
South Central Nebraska
I am having an issue with the reflect meter jumping up on my ATR-30 tuner anytime the forward power is near legal limit. The tuner and antenna system are not arcing, I have heard that before when it was badly mistuned. I'm thinking the meter diodes are breaking down. Also it seems like it is only a matter of time anyway before MFJ meter diodes need replacement due to failure.

Some online reading indicates that the meter replacement diodes are 1n34a with a possible upgrade being a 1n60. If these numbers are incorrect please let me know. Thank you on advance!
 

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Posting this in case anyone else runs into an issue of the ATR-30 tuner reflect meter pegging at higher power levels.
I think I have resolved the reflect meter hitting the stop peg when running at legal limit. I noticed that any time I was on a band that the transmitter capacitor was more open I would have the issue, and when it's more open it is closer to the meter board. Sooo, thinking that RFI in the meter board was causing this, I took a stab in the dark. First I tried removing the battery lead that I don't use, this didn't help the meter pegging. Shielding the meter board with aluminum as shown stopped it from happening. Don't, judge my metal working skills, i only have a vice, pliers and a hammer to form it.
 
Rock on! This is the hidden weakness of active peak-reading meter circuits. If enough stray RF leaks into the pickup circuit, wacky readings follow.

Congratulations for sticking with it. Can't believe you're the first one to have this problem.

73
 

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