[Elecraft] K1 sidetone overpowers headphones

Sun May 4 14:46:02 2003

I also have noise cancelling phone which hum during transmission if the
noise cancelling is on. It almost disappears if I wind the cable many
times through a toroid core that I had lying around, it is about 25-30
mm outer diameter I would guess.

73, 
Sverre

------------------
Sverre Holm, LA3ZA
www.qsl.net/la3za

> -----Original Message-----
> From: [email protected] 
> [mailto:[email protected]] On Behalf Of Dave 
> Gingrich K9DC
> Sent: 4. mai 2003 20:32
> To: Robert J Greenwalt Jr
> Cc: [email protected]
> Subject: Re: [Elecraft] K1 sidetone overpowers headphones
> 
> 
> 
> On Sunday, May 4, 2003, at 09:04 EST, Robert J Greenwalt Jr wrote:
> 
> > Don't know if this is an unusual situation or not -- My K1 
> works fine
> > on
> > speaker but when I plug in a set of Bose noise cancelling phones the
> > sidetone during keying becomes an overwhelmingly loud 
> crashing tone in 
> > the
> > phones.  Its almost painfully loud.  When I set the K1 
> output to zero 
> > the
> > keyer sounds fine in the headphones.  When I turn the power 
> back up to
> > actually transmit, I get the crashing effect.  Reducing the 
> StL level 
> > has no
> > effect.  The Bose phones have an audio amplifier in the line to 
> > produce the
> > noise cancelling effect -- could RF be causing this?
> 
> Probably yes. I also have the same Bose headphones. Totally useless 
> anywhere near anything resembling RF.
> 
> ===========================
> Dave Gingrich, K9DC
> Indianapolis, Indiana USA
> ===========================
> 
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