[K3PZN-List] Curious behavior from my mobile radio...

[Curt Milton]

Bill

interesting mystery but it may not be worth too much
attention is trying to figure it out.  

since it is location and frequency dependent, it
appears to be a situation in which some combination of
RF signals either produces 145.410 or some other
frequency that your rig responds to when its tuned to
145.410.  

by other signal i would mean an image or a mixer
spurious response.  the filtering and linearity of
these rigs is finite - and we would want to spend the
2-10x what it would cost for a few dB in more
performance!  and since the intermediate frequency and
filtering are different in different rigs, not all
will behave the same way.  perhaps another rig the
same model would behave the same way, and a different
model rig may be vulnerable with a different
combination of signals.  

squelch and s-meter behavior vary greatly amongst this
class of rigs, and it sounds like you squelch is much
more sensitive than your s-meter.  

if the rig is still working this well after 13 years
-- keep it and use it!  

73, curt

--- "Neeriemer, Bill (NIH/NLM/LHC) [C]"
<bneeriemer at mail.nih.gov> wrote:

> I have an Alinco DR-119T mobile radio in my truck. 
> It is ~13-14 years
> old.
> 
> Steve checked it out this year, and pronounced it in
> good shape.
> 
> It appears to be very sensitive on the receiver
> side.
> 
> I've discovered that when driving around
> Westminster, the squelch will
> break open on a signal, which registers no power on
> the S-meter.
> 
> This happens regardless on the squelch setting. 
> However, my Yaesu VX7
> doesn't detect anything.
> 
> It only happens on 145.410.  I have checked other
> freqs, although, it
> wasn't a comprehensive analysis.
> 
> I wondered if my radio's circuitry is faulty, but if
> that were the case,
> then I would expect the squelch breaking to be
> random, but this isn't
> random.  That is, if my squelch breaks in a
> location, it always breaks
> in that location.
> 
> The squelch breaking is 'stroby'. That is the areas
> that it breaks are
> very confined.  If I drive forward a couple of feet,
> it stops.  It isn't
> time based, because if I back up, it returns.
> 
> Also, whatever is causing it, it is continuous, if I
> stay in a noisy
> zone, the squelch remains open until I leave.
> 
> I don't think that it is a modulated signal, because
> I hear nothing but
> static.
> 
> I mentioned this at the BoD meeting, and heard that
> electric motors can
> cause this.
> 
> While, I haven't checked too far from Westminster,
> so far, I have only
> noticed this is downtown Westminster.
> 
> Have others noticed this behavior?
> 
> Comments?
> 
> 73 Bill W3STG
> 
>  
> 
>
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> 
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