[Elecraft] Birdie ?

[Geoffrey Mackenzie-Kennedy]

That figures, this birdie gets to the point of entry into the signal path 
via two birth routes, so it is not surprising that the strength of this 
birdie is different receiver to receiver. The dominant source of this birdie 
is the PLL refernce oscillator which is 'heard' by the 2LO - IF spurious 
response of the receiver when tuned to 3590 kHz approx.   2(3590 + 4914) - 
4914  =  12094 kHz,  if the IF = 4914 kHz.

If of any help, the point of entry into the signal path of my K2 was centred 
in the region of the relays K16 and K17 (attenuator and preamp switching), 
via two birth routes. There was the radiated signal from the PLL oscillator 
picked up by the pcb trace D6 - relays - mixer input , and a conducted 
signal entering via one or both of the relay coil circuits. I need to see my 
notes which are not here to be certain whether it was via one relay coil or 
both.

The other potential birdies around this frequency were at or below my K2 
receiver's noise floor IIRC when using a dummy load at the input.

73,
Geoff
GM4ESD



----- Original Message ----- 
From: <w7qhd at cox.net>
To: <elecraft at mailman.qth.net>; "Ken Kopp" <k0pp at rfwave.net>
Sent: Saturday, July 19, 2008 11:51 PM
Subject: Re: [Elecraft] Birdie ?


> OK. I give. With the antenna off I hear the birdie. It's S-0. With the 
> band noise on 80 I can't hear it with the antenna on even in mid day.
>
> Kurt W7QHD