[Elecraft] When to use the preamps on the KX2/KX3 vs. K3/K3S

[Edward R Cole]

Just to add a little info, I measured and compared my KX3-SN475 to my 
K3-SN4043:
http://www.kl7uw.com/HF.htm  Half-way down the page.

KX3 on 6m with preamp on was -127 dBm with 2.8-KHz SSB*
K3 on 6m with ARR Gasfet preamp was -137 dBm*
on 10m the K3+PRE outperformed the KX3, as well

Subsequent to this testing I acquired a PR6-10.  I helps the K3 
tremendously but not quite as much as using the ARR preamp**. 
Subjective impression is the PR6-10 equals the KX3 in MDS.
*Add 7.5 dB for MDS at 500-KHz bw
** Uses mgf-1302 GasFet with 0.5 dBNF and 25 dBG

I don't own a KX2

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   dubususa at gmail.com