[Elecraft] K3 wih - PA3AKE High Pergormance Front End

[Geoffrey Mackenzie-Kennedy]

David,

May I get back to you later this evening off-list with some thoughts about 
this approach. An advantage gained by using a variable IF is that the 
close-in phase noise of the first mixer's fixed frequency LO injection can 
be very low indeed, but there are other disadvantages.

The gain of Martein's front end between the antenna port and roofing filter 
input is negative, about -7 db depending on the band in use, since neither a 
post mixer amp nor a preamp is used neither of which is desireable nor 
necessary. This means that the IF's noise figure has to be low in the region 
of 2 db.  Also the Input IP3 of the IF has to be +50dbm, or better if at all 
possible, to take full advantage of this front end's performance.

73,
Geoff
GM4ESD


David Cutter G3UNA wrote on Monday, April 14, 2008 12:57 PM

>I would like to consider this front end and the K3 as tunable IF, does that 
>sound do-able?
>
> David
> G3UNA