The problem with any noise blanker comes down to how they work. When a high
noise spike is detected, the audio is blanked for a very short time (like 10
milliseconds). If a strong station comes on that is in the noise blanker
passband but not in the receiver passband and is stronger than the noise,
then the noise is not heard by the noise blanker, so the blanker does not
blank the audio while this signal is on. What you end up with is the noise
appears to be modulated by the strong signal. That is you only hear the
noise while the strong signal is on. This is not intermod, but just the
noise blanker not hearing the noise while the strong signal is on. This is
hard to explain but once you think about, you should get the idea.
Carl Moreschi N4PY
121 Little Bell Drive
Bell Mountain
Hays, NC 28635
----- Original Message -----
From: "Kim Elmore" <cw_de_n5op@sbcglobal.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Saturday, January 27, 2007 6:14 PM
Subject: Re: [TenTec] ORION2_HW-NOISE_BLANKER
> I have only had to use the HW noise blanker a couple of times on my O
> II. I noticed an increased susceptibility to intermod, but then I've
> noticed that even with adjustable HW noise blankers. In almost all
> cases, if I backed off on adjustable blankers enough to mitigate the
> intermod problem, they were backed off so far that the noise problem
> had returned.
>
> Kim Elmore, N5OP
>
> At 04:40 PM 1/27/2007, you wrote:
> >The hardware noise blanker is too aggressive in my Orion2. I have
> >power line noise on 160 meters and a variable HW noise blanker would
> >be useful if it could be cut back some. Currently, when I invoke the
> >HW blanker, and there are strong signals near the listening
> >frequency, it is murder on the listening frequency.
> >My question is: Why would Ten Tec not have allowed for a variable HW
> >noise blanker in this high end radio? The SW blanker is useless.
> > Does anyone else have this problems with the O2 HW noise
> > blanker with near by strong signals up and down the band creating
> > problems to the listening frequency?
> > Thanks.
> > George W2YJ
> >
> >_______________________________________________
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> >TenTec@contesting.com
> >http://lists.contesting.com/mailman/listinfo/tentec
>
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