[Elecraft] K3 with SDR-IQ

[Dave G4AON]

Paul, I use a Perseus SDR (see QST for December 08 for the review, also 
on the members site). Perseus has a USB2 interface rather than the 
narrow band sound card approach. I don't use the IF out of the K3 with 
Perseus, but connect them in parallel using an outboard ferrite splitter 
on the RF IN/OUT of the K3's KXV3 interface module. Frequency "linking" 
them via Ham Radio Deluxe so that either the K3 tunes the Perseus or 
vice versa. The combination works very well, indeed the noise reduction 
in the Perseus is superior to that in the K3. The receiver performance 
is similar for both as the Perseus has a 3rd order IMD of 97 dB at 2 KHz 
spacing.

The only downside to Perseus is the current lack of support from 3rd 
party programs which seem to favour the 192 KHz bandwidth simpler SDR 
receivers (Perseus has 1600 KHz bandwidth). There is a comparison of 
Perseus vs. SDR-IQ at: http://www.ssb.de/amateur/pdf/radcom_mar08.pdf

73 Dave, G4AON
K3/100 #80

Has anyone had an opportunity to compare LP-PAN with the SDR-IQ using
SpectraVue? I am interested in using the K3 in a compact, portable
environment with my laptop PC where I would like to avoid the use of an
external sound card if possible, and the SDR-IQ seems to meet this
requirement.

Moreover, with the N8LP I.F. buffer mod conducted on the K3, is there any
reason to pursue any further I.F. level or impedance optimization when 
using
the SDR-IQ? Tnx!

Paul, W9AC