[Elecraft] Re: Binaural CW Reception

[Mike Scott]

When I brought up binaural capability for the "dual receiver K3" I had
thought of the approach taken in the March 1999 QST where I and Q data out
of the detector are preserved all the way to the headphones, nothing
different is done in the two channels other than preserving the 90 degree
phase difference.
This approach requires dual channel processing from the I-Q detector through
separate filter, BFO and audio stages. The two BFOs would use the same
oscillator. When tuning through a signal the spatial separation effect on a
CW signal is similar to that previously described by splitting a single
audio channel into separate low and hi-pass filter stages but there is no
hiss in the high pass channel. Each ear hears the same pass band; it is just
the signals that separate three dimensionally. 

The other approach to binaural operation is to connect two spatially
separated antennas to two complete receiver chains tuned to the same signal.
One ear gets the I-channel and the other ear gets the Q-channel. This is the
reason I wanted to slave the two receivers to tune a single signal but from
different antenna inputs.


Mike Scott
AE6WA
Tarzana, CA (near LA)
Elecraft KX1 4-Watts


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Darwin, Keith
Sent: Thursday, May 25, 2006 12:14 PM
To: elecraft at mailman.qth.net
Subject: RE: [Elecraft] Re: Binaural CW Reception

 

-----Original Message-----
From:  Jerry Volpe
Sent: Thursday, May 25, 2006 2:35 PM

My second project began with the following in mind:
1. Using band-pass filters rather than low-pass and high-pass.
2. Include the ability to move the combined filter cross-over for
different CW offsets.
3. Get the lowest distortion possible in the filtering.
4. Use something commercially available rather than 'build your own'.

---------------------

There is an easy way to do this with commercial gear.  Get a pro sound
crossover unit.  Behringer (*spit*) makes some for about $100 new, maybe
less.  It gives you the ability to adjust the crossover frequency plus
other features you probably don't need.  Most of these are 18 or 24 dB
per octave which may cause rather abrupt shifting of signals from L to
R.

Feed the audio signal into the unit, pick your crossover freq.  Feed the
high & low outputs to your headphone amp, one to the L, the other to the
R.

Maybe I'll borrow the Xover from church and try it with my mini
headphone amp...

- Keith KD1E -
- K2 5411 -


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