Noise when Microphone is Initially Keyed

Rick N4RZ

I have a 6500 and when I key the microphone others were hearing a noise spike at the start of the transmission. I confirmed this myself by listening to another receiver and then noticed that you can even see the noise spike on the panadapter. It sort of sounds on the air like a squelch tale but at the start of the transmission instead of the end. Is there anyway to eliminate this problem?

Carl/K5HK

Sounds like a mechanical noise type thing from acuating the ptt. try Vox and see if it goes away. VOX in the 6500 works wonderfully.

Ken - NM9P

I had noticed a similar noise a few months back and finally traced it back to a combination of several things 1) a sensitive, high fidelity mike (PR22UT - I love it!) 2) High compression level, which allowed the rig to pick up the noise made by: 3) A sudden inhale of breath as I prepared to talk as I hit the footswitch....and 4) vibrations form the rig's relay transmitted through the desk and boom to the mike. These combined to produce a loud burst of sound upon PTT. I solved the noise by: a) Controlling my breathing better (The compression reduces gain after I start talking and the breath noise isn't as severe.) b) not using as much compression if I didn't need it, c) adding a shock mount to my boom to isolate the mike from the desk. The shock mount also helped the VOX to be more predictable, because it no longer picked up as much of my finger tapping and other impact noises on the desk. BTW: the VOX on the 6500 works wonderfully IF you are using headphones. It needs a good Anti-VOX if you are going to use stereo speakers. Good luck!

Charles - K5UA

Had this problem myself. I dont have a good radio voice, and I could not drive version 1.0.0.0 audio to the proper level to show any compression. So I pulled out my trusty 528E Symetrics Voice Processor and drove the audio very nicely with line level output from the 528E. Along comes version 1.0.0.5 and I start getting this squelch tail, not at the end of the transmission, but at the beginning. About a half second of an audio spike that showed up on the panadapter as well as the transmitt audio. Plus, I started getting unfavorable audio reports. I opened up the 528E and selected "mic level" output and everything returned to normal. So the problem is way too much gain in the audio circuit. My guess is that version 1.0.0.5 has more gain in the the audio circuit than 1.0.0.0. Check the +20 db button under setting and deselect it to see if that eliminates the "thump" you are hearing and seeing. Somehow, you are driving the audio too hard. Hope this helps.

Tim - W4TME

I have converted this topic to a Problem from a Question to Problem topic. Second, this behavior has been previously reported and has been entered into our bug tracker for further investigation. Thanks for the report.