Message-ID: <3928FF9C.1851@xtra.co.nz>
Date: Mon, 22 May 2000 21:36:28 +1200
From: "vernall" <vernall@xtra.co.nz>
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To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Re: Morse tones / filters etc.
References: <006201bfc359$2a3a9050$0a00a8c0@server1.ThreeLakes.ca> <004601bfc3c4$6ebc3e20$de1886d4@kevin>
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Kevin Ravenhill wrote:
> 
> > a visitor told me the "sweet spot"
> > was probably were the two ears were copying best was were there was a
> phase
> > shift in the audio approaching 90 degrees thus giving what we now know is
> > the extra sensitivity of the I and Q channel reception condition.
> >
> > Larry
> > VA3LK
> 
> I have also experienced noticeably easier copy of weak CW in noise when at a
> distance from the headphones - in fact I find that turning up the AF gain a
> bit and leaving the headphones on a table provides an effective method of
> monitoring activity whilst doing other things. I must admit, though, that I
> have not been aware of any definite "sweet spot" whilst moving around the
> room.
> 
> Has anyone experimented with phase shifted / delayed audio, i.e. with "raw"
> audio fed to one half of the headphones and a (variably) phase-shifted /
> delayed version fed to the other half?
> 
> Kevin
> G1HDQ

I was thinking on similar lines.  My suggestion is to electronically
simulate "walking around" by processing the audio to one of a pair of
"stereo" speakers.  It should be possible to sweep the phase shift of
the feed to the second speaker (or headphone earpiece) with an
electronically controlled all-pass network, and sweep at much higher
phase rates that are equivalent to "running around" the shack.  Sort of
a couch potato similation :)

Bob ZL2CA