[TenTec] Noise

[Duane A Calvin]

Turning on the noise blanker causes the dynamic range of the RX to suffer
substantially.  That's why you'll get garbage from nearby stations when
you turn it on.  The reason CW tones sound raspy is because the blanker
is essentially killing your RX for the few microseconds that each noise
pulse occurs.  So, you hear a CW tone with all those slices removed from
it, making it sound "buzzy".  It's normal with loud noise, noise blanker
on, and a CW signal behind it.  Because SSB waveforms are much more
'random' the effect is not quite as noticeable, but still obvious when
the noise switches on or off.

        73,  Duane


On Sat, 11 Dec 2004 17:43:04 -0600 Ron Feutz <feutz at wctc.net> writes:
> TT'ers,
> 
> I have some ugly new noise at the QTH.  Starts out low and quickly 
> builds 
> to S 5-6 (RF gain up, 500 hz filter) for 10-20 seconds, and then 
> abruptly 
> stops.  It seems to cycle about once a minute.   The Omni 6+ NB does 
> a good 
> job on it, but when a strong adjacent signal starts up (within 10 
> Khz or 
> so), I hear the guy's CW as raspy noise in my passband, and its 
> strong 
> enough to wipe out  weak sigs.  The occurs when the noise is strong. 
>  When 
> the noise is absent, I don't hear the garf from strong adjacent 
> sigs.
> 
> Any idea on what  this type of noise is?  If its from a power line 
> or 
> transformer, would it cycle like that?(I'm going fox hunting with a 
> 
> portable AM radio tonight).
> 
> What causes me to hear the raspy CW when the noise is there, but not 
> when 
> it isn't, and is there anything I can do about that?
> 
> 73,
> 
> Ron - WA9IRV
> 
> 
>    
> 
> 
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> 


--------------------------------------
Duane Calvin, AC5AA
Austin, Texas

http://home.austin.rr.com/ac5aa