[Elecraft] A/B Receiver Evaluation

[Darwin, Keith]

I have a different A/B approach that I've used with a number of rigs.

1.  Hook the same antenna to each rig in parallel.  This may require
some custom cables depending on the rig.  Since all you're doing is RX,
it doesn't have to be perfect, just get the same sig to all rigs.

2.  Run speaker outputs from both rigs into your Mackie 1202VLZ mixer.
Or, if you must, your Behringer mixer.  Set the volume output of your
rig for best S/N ratio.  Trim the mixer's input channel to get each RX's
signal up to about 0 dB.

3.  Plug your headphones into your mixer.  Now you can A/B by simply
muting one or the other.

This approach really lets you hear the differences.  Both rigs,
connected to the same antenna, listening to the same signal at the same
time, feeding the same headphones.  You can even do things like pan one
L/R or put both rigs in mono and just switch between them.

Differences in AGC action, background noise, filter performance and
overall tone become immediately apparent.  Like night and day.

I did this with a number of rigs:
  IC735
  Drake R4A
  K2
  Drake 2B
  Kenwood TS830s

After my testing I had the rigs stacked in order of best RX performance:
  K2
  TS830s
  Drake 2B
  R4A
  IC735

See if you can guess which rig I kept :-)

- Keith N1AS -
- K2 5411.ssb.100 -


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Ed Muns
Sent: Monday, September 24, 2007 1:46 AM
To: 'Elecraft Reflector'
Subject: [Elecraft] A/B Receiver Evaluation

With the KXV3 option in the K3, it is very easy to do real-time receiver
comparison testing between the K3 and brand X.