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Noise Blanker circuit found

 

Here is a link to the manual for a Noise Blanker for the KWM-2.? See:

Two pentodes, two dual section triodes and eight Germanium diodes plus associated components.? Monitors the noise at 40mc and gates the IF signal in the KWM-2.? Not a simple solution but perhaps quite effective.
Regards,
Jim
Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy


On Monday, June 10, 2024 at 07:20:02 PM CDT, Jim Whartenby <old_radio@...> wrote:


I've looked and have not found a radio that uses a noise blanker.? All I have seen is clippers which remove noise spikes above a set level.? The guitar guys mention it but it is a squelch gate which is open below a set value and closes above this set level.? So audio is muted for very low passages; one assumes to remove background hiss.
Regards,
JIm


Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy


On Monday, June 10, 2024 at 07:04:29 PM CDT, don Root <drootofallevil@...> wrote:


Thanks jim, but first, is/has this topic swung to dealing with ignition noise only?? For an SX-117 ??? . interesting discussiuons, but what is the scope of it? Help..I¡¯M lost??? ¡­. again. don

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From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Monday, June 10, 2024 3:58 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] SX-117 noise limiter behavior

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Don

Read the enclosed excerpt from TM 11-310.? The first page shows the noise antenna circuit and lists all design changes to the series of receivers.? I would think that the noise antenna would be short so as to only pick up ignition noise.? Anything longer would subtract form the signal of interest.

Regards,

Jim

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Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy

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On Monday, June 10, 2024 at 01:55:22 PM CDT, don Root <drootofallevil@...> wrote:

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Maynard, your theory sounds mostly good, but we need some details on what is called an antenna; will it work with my 10 feet of haywire antenna?

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From: [email protected] [mailto:[email protected]] On Behalf Of Maynard Wright, P. E., W6PAP via groups.io
Sent: Monday, June 10, 2024 2:22 PM
To: [email protected]
Subject: Re: [HallicraftersRadios] SX-117 noise limiter behavior

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The operation of a noise antenna and associated circuitry are
independent of the nature of the noise, whether or not it's periodic and
whether or not it's random.

Ideally, the signal antenna would receive the signal plus the offending
noise and the noise antenna would receive just the noise. The combining
network would be adjusted to combine the two signals so that their time
domain noise components would be equal in amplitude but opposite in
polarity so that they would cancel and leave only the desired signal at
the input to the receiver.

There are several potential difficulties that make this system less than
perfect in most, if not all, implementations, but it may reduce the
noise enough to be useful in some situations.

73,

Maynard
W6PAP


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don??? va3drl ??


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don??? va3drl

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