[Elecraft] K3 BUFFER MOD?

[Richard Ferch]

Bill,

I am sure you will get more expert advice than I can give you on this, but
so far I have not found the buffer mod necessary with my LP-PAN - right now
I have only a vertical antenna and have only tried the LP-PAN out on low
bands, where band noise alone is clearly visible on the display even without
the mod. You may feel differently if you are using directional antennas on
quiet bands, but my suggestion would be to start out without the buffer mod
and see how well your LP-PAN works without it.

Although I have installed the Audio line out mod myself, I think it probably
won't make any difference to LP-PAN operation, since the LP-PAN does not use
line out. However, I found that the mod to bypass RF chokes in the ground
return lines made a big difference:
(<http://www.elecraft.com/K3/mods/ELECRAFT_Application_Note_Improving_the_Im
munity_of_the_Rear-Panel_KIO3_RS232_and_Audio_Connectors_to_RF.pdf>, or go
to <http://www.elecraft.com/K3/k3_app_notes.htm> and scroll down to the link
"Improving the Immunity of the Rear-Panel RS232 and Audio Connectors to
RF"). Before making this change, I was seeing a lot of polling noise from
the radio control serial port on the PowerSDR display. Bypassing the choke
in the RS232 ground return seems to have helped a lot in my case - YMMV, of
course.

73,
Rich VE3KI
K3 #1595


N4ZI wrote:
> Guys,
> 
>   Later today I will start building my LP-PAN kit - I was wondering
> if the K3 Buffer mod that is recommended will void the warranty
> on my radio? Is it really worth the effort? Where is best place to
> attain parts? I have the K3 Audio line out mod kit to do figured
> I should probably do it all at the same time? My S/N is 1059
> 
> Thanks and 73,
> 
> Bill N4ZI