[Elecraft] [k3] 6m birdies

[Johnny Siu]

Hello Don,
 
I would even play a more safe game to distinguish whether it is a true birdie.  How about using a 12v battery instead of a power supply unit during the test?

TNX & 73,


Johnny VR2XMC

從︰ Don Wilhelm <w3fpr at embarqmail.com>
收件人︰ "elecraft at mailman.qth.net" <elecraft at mailman.qth.net>
傳送日期︰ 2011年07月7日 (週四) 8:35 AM
主題︰ Re: [Elecraft] [k3] 6m  birdies

  It may just be my more or less casual observation, but ---

Many seem to becoming "loose" on what is defined as a "birdie".
Proper use of the term is to refer to a "fast tuning" signal that is 
produced by the receiver's mixing scheme and the harmonics thereof.  
That is a true "birdie".

Other annoying signals can be heard which originate from something other 
than the receiver itself.  Those signals are real signals (whether 
desired or not) that are picked up by the antenna.

For true receiver birdies, re-orienting the TMP cables and/or the use of 
the Signal Removal Tool in the K3 can be effective, but for signals that 
originate outside the K3, the only real cure is to suppress them at the 
source.

Yes, I understand that identifying the true source can be a burdensome 
chore, but differentating between internal receiver "birdies" and 
external signal sources is a good starting point.  Terminate the K3 
antenna input with a well shielded dummy load (with a very short length 
of coax), and if the "birdie" is still present, it is a true receiver 
birdie, but if it is no longer present, it is a real signal and the 
source must be found to eliminate it with ferrites or other suppression 
devices.

73,
Don W3FPR

On 7/6/2011 6:04 PM, Mike Rodgers wrote:
> I have a birdie at 50.09465 cw  normal not rev on a cold k3 and the one at 14.186. The latter being weaker and neither adding to the s meter. My shack has no computers but a wal wart or two so I can confirm those two.
> Auto notch has no effect.
>
> I believe as Tom mentioned there is a method to remove them or that specific frequency they are on ( not sure which) but I havnt been bothered enough by them yet.
>
> 73
> Mike R
>
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