Re: serial interface noise on 160m -- propagates through K3

classic Classic list List threaded Threaded
1 message Options
Reply | Threaded
Open this post in threaded view
|

Re: serial interface noise on 160m -- propagates through K3

Richard Ferch
Mitch,

Has your K3 had the modification described in
<http://www.elecraft.com/K3/mods/ELECRAFT_Application_Note_Improving_the_Immunity_of_the_Rear-Panel_KIO3_RS232_and_Audio_Connectors_to_RF.pdf>
performed on it - specifically, bypassing L1 as described at the top of
p.4 of the application note?

I had serious noise pickup on the IF output from my K3, which pulsed in
time with polls from my radio control software. The source was a
USB-to-serial adapter connected to the K3's RS-232 jack. After I
performed the above mod the problem disappeared. I did several other
mods at the same time, so perhaps it wasn't this one that did the trick,
but I suspect that it is what solved my problem.

73,
Rich VE3KI
K3 #1595


> Thanks to everyone who responded -- as far as directional antennas go the VX-3R yahoo \
> group pointed out that the hand held has a fairly directional AM antenna that can be \
> use to chase down noise.
>
> I have been able to narrow the source of the noise down to the USB to Serial \
> converters or the USB Hubs themselves.  The noise is getting into the ground through \
> the serial interface on the K3 and then out to the coax shields.  I'll have to move a \
> heavy desk to determine which of the two potential offenders is actually generating \
> the noise.
>
> I was curious if anyone else had experienced this with a K3 and USB<->Serial \
> converters -- the pulsing of the noise turns out to be HRD polling the K3 for VFO \
> position -- once every 300ms -- and when I turn off polling the noise stabilizes but \
> is still present.  I am doing research to see what I can do to eliminate it.
>
> While chasing this down with my HT,  I found several other sources of noise -- all \
> within my shack, so I have a noise eradication project to embark on now.
>
> 73,
> Mitch Mitchell, AE5HO
> [hidden email]
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html