[Elecraft] K3 birdies - question?

[Geoffrey Mackenzie-Kennedy]

David,

Double shielded coax would certainly reduce leakage from the coax, and is a 
good investment in my opinion. However its use might not have too much 
impact on the receiver's birdie problem, because many of the "rogue" signals 
involved are probably flowing on the outside of the coax's braid, certainly 
if the coax emerges from some enclosure through a hole.

The usual cause of a receiver birdie is that some response of the receiver 
is "hearing" some oscillator or a harmonic, or some mixing product of two or 
more oscillators, contained within the receiver. In a down conversion HF 
receiver, the great majority of the receiver's responses, therefore the 
"rogue signals", that cause birdie problems are at HF and up to low/ mid 
VHF, which means that choking off coax runs within a receiver becomes 
cumbersome.

73,

Geoff
GM4ESD

David Cutter wrote on Wednesday, March 04, 2009, at 10:32 AM:

>I also wonder if it would be worthwhile buying higher spec coax.  Don't 
>know what is used in the K3, but for the lengths involved it would be worth 
>the investment to get short cables made in say LMR100 or RG142 etc if it's 
>not already
>
> David
> G3UNA