[Elecraft] K3: listening to both rcvrs

[Mike Cox]

I think the questions regarding addition of noise from one Rx to the 
other Rx are interesting but not entirely relevant  to my own use of the 
dual receivers for split frequency DXing.

Here's the way I normally deal with a split frequency pileup (using a CW 
pileup as an example). Remember that myself and numerous others copy 
much better when the signal is coming in BOTH ears (sounds like it's in 
the middle of the head) as opposed to only ONE ear. We'll say the DX has 
split a couple of KHz up the band and the pileup is several KHz wide. My 
main Rx is on the DX and I'm in the split mode with the SUB Rx ON (I 
will transmit on the sub Rx freq). The main Rx is set very narrow 
(usually 100 - 300 Hz wide). The sub Rx is set about a KHz or more wide 
so I can hear a greater swath of pileup signals and listen for the 
station the DX is currently working. Here's how I run the audio with the 
Orion or Kenwood (using headphones):

Left Ear: Main Rx ONLY (DX station only, NO added noise from the sub Rx)
Right Ear: Main + Sub Rx (combine the two in phase) This is also my Tx 
frequency.

Here is what my brain perceives: The DX is in the middle of my head and 
is easy to decipher (much easier for me than if the DX was only out to 
my left). The pileup and most of the noise are outside of my head, 
somewhere to my right side. It becomes a simple matter to pay attention 
to the right side pileup and tune for a responding signal while the DX 
station is not transmitting. Even though the pileup may not quit calling 
while the DX station sends, when the DX station is on, it is very easy 
to ignore the noise out to the right side and concentrate on what the DX 
station is sending in the "middle" of my head. Even with the weakest DX 
signals, I seldom ever turn off the sub Rx. The noise is simply ignored 
in my head at the appropriate times. When scanning the pileup for the 
"workee" on the right side, it is not necessary to achieve a solid copy 
but only to recognize that magic "599 TU" report. Then you know you are 
nearly on the spot the DX station is currently monitoring. The 
additional noise added into the right side from the main Rx is not 
really an issue and, in fact, it only becomes harder to copy stations in 
the pileup during the DX stations' transmissions. That's not really a 
bad thing since the DX station achieves a "perception priority" over the 
bedlam of the pileup. The DX is in BOTH ears. The noise is only in ONE 
ear. If the DX is in the left ear only, it only achieves, at best, 
parity with the pileup in the right. By the way, the bedlam of the 
pileup is usually many dB louder than the typical band noise so the 
discussions of additive noise floors are really about a miner annoyance 
compared to hundreds of transmitters pounding out their calls in the 
pileup. Depending on the loudness of the pileup and how well your brain 
has adapted to this system, you simply adjust the sub Rx volume so that 
it doesn't detract from the copy of the DX station. That way, for me, 
the DX station always achieves the magic priority over the pileup in my 
organic signal decoder.

I currently run the K3 with stereo speakers. I set in front of the left 
speaker and place the right speaker at my far right. For me, it works 
better for copying the DX than using the headphones with the DX only on 
the left side. It's the simplest of audio mixers. An SSB pileup is 
handled the similarly except the passband of the sub Rx is not opened up 
beyond normal voice response. I surely would like to use the "cans" so I 
can get rid of the computer and fan noise!

Anyway, that's the way my brain does it best.

Good DX,
Mike, AB9V
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