[TenTec] TT Orion 2 and Yaesu CM-500 - RF problem sorted! - classic Pin 1 issue

[Steve Ireland]

G’day

After careful investigation (and reading some of Jim K9YC’s work on the matter), I found that the reason for RF getting into the CM-500 was a variation of the classic ‘Pin 1’ problem. 

Basically I had managed to connect my mic ground to the rig ground through placing the homebrew interface inside a aluminium diecast box (where the sleeve connection of the interface CM500 mic jack socket connected to earth) and using the stereo jack plug that came with the Yaesu CM-500 microphone plug. 

Once I had removed the CM-500 mic jack plug and replaced with another plug where my CM-500 mic connections were carried by the ring and the tip of the plug, and rewired the interface mic plug accordingly, everything fell into place.

Isolating mic ground from the rig ground, along with making sure the interface aluminium box was connected to the rig ground, stopped the RF from getting into the CM-500 electret element.

Thanks again for the assistance.

Vy 73

Steve, VK6VZ

   

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