[Elecraft] Background Noise with Mike Plugged in to Rear Mike Jack

[David Herring]

I also had RF problems with the CM-500 plugged into the rear mic jack.  The solution I’ve implemented so far was to wrap about 13 turns of the CM-500’s cord around a #31 toroid. It both shortened the cord which was way too long for my shack and eliminated the RF problem. A two-for-one solution. ;-)

On rare occasions I like to use my D-104 mic in the front panel jack.  It too is adversely affected with RF issues.  As soon as I get a moment I’m going to try wrapping it’s cord around a #31 toroid and hope it works as well there as with the CM-500.

I hope Elecraft is looking at the front panel mic jack as well as the rear when looking at solving the RF issue.

73,
Dave - N5DCH




> On Nov 21, 2021, at 6:40 PM, Rick Tavan <rick at tavan.com> wrote:
> 
> Hi, Pete. Try a dynamic mic or use the front panel (ugh) mic connector.
> I've had RFI problems at high power using a CM-500 on the rear panel mic
> jack. Elecraft are working on a fix. My Heil headset with dynamic mic works
> fine.
> 
> 73,
> 
> /Rick N6XI
> 
> On Sun, Nov 21, 2021 at 5:32 PM Pete Smith N4ZR <pete.n4zr at gmail.com <mailto:pete.n4zr at gmail.com>> wrote:
> 
>> I don't normally operate phone, but wanted to contribute a few QSOs to
>> my club in SS SSB.  So I recorded messages on my external USB sound
>> card, using Audacity.  They sounded fine, both on a speaker and on my
>> K3's monitor.  So then I plugged my Yamaha CM-500 condenser mike headset
>> into the rear microphone jack, with MIC SEL = rP.L bIAS.  That worked
>> OK, but there was a very high level of white noise, audible both with
>> live voice and while playing recorded contest messages.  I was reading
>> 700 watts out without talking.
>> 
>> Experimenting, I discovered that the source of the noise was definitely
>> the mike on the rear microphone jack.  I also didn't like the fact that
>> in this setup the mike was live while recorded messages were playing.
>> 
>> How can I rig things so that the mike doesn't contribute this high level
>> of background noise, and how can I manage things so that the microphone
>> is muted when the recorded messages are playing through the line in jack.
>> 
>> --
>> 73, Pete N4ZR
>> Check out the new Reverse Beacon Network
>> web server at <http://beta.reversebeacon.net>.
>> For spots, please use your favorite
>> "retail" DX cluster.
>> 
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> 
> 
> 
> -- 
> --
> 
> Rick Tavan
> Truckee and Saratoga, CA
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