[App_rpt-users] Interesting problem

Ken ke2n at cs.com
Sat Nov 24 13:09:34 EST 2012


You say 'underneath' the transmit audio, so I am guessing it is a low volume
level tone. 
I have had various hums/tones show up that I eventually traced to ground
loops.
Use of switching supplies for the computer and radio make for lots of
interesting "notes".
The URI has no transformer isolation, so is particularly susceptible to
this, under certain circumstances.

The cure was simple and effective: a short heavy wire between the computer
chassis and the transmitter chassis.

73
Ken
KE2N



> -----Original Message-----
> From: app_rpt-users-bounces at ohnosec.org [mailto:app_rpt-users-
> bounces at ohnosec.org] On Behalf Of Bryan D. Boyle
> Sent: Saturday, November 24, 2012 11:51 AM
> To: app_rpt mailing list
> Subject: [App_rpt-users] Interesting problem
> 
> I have a simplex node (that I finally got working...); alinco DR135, that
I use as
> an occasional link from my node(s) into the local club repeater (trying to
> demonstrate for them the wonders of asterisk...).
> 
> The DR135 is set up for digital input, levels are ok, keying off the ptt
on the
> rear connector.  I can connect ok, get good modulation in both directions,
PL
> works fine (i'm taking flat audio out of the 135 and injecting back in
with
> asterisk handling the pl generation, etc.)
> 
> Anyway...have an interesting problem that cropped up...when I connect the
> 135 to ANY of my 2 hubs or nodes and confirm the connection...my transmit
> side (listening on the transmit frequency of the link radio), when I key
the
> 135, has a 1KC tone underneath the transmit audio.
> 
> I've checked (via radio-tune-menu) that the 1KC tone is off, all the
> configurations are saved properly, etc.  This ONLY happens when I connect
> the DR135 up as a simplex link; it does not happen between any of my other
> repeater nodes.
> 
> It's a bit of a quandry...wondering what this could be.  Any thoughts?
> 
> BB
> 
> 
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