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Noise Blanker Wish List.

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Geoffrey Mackenzie-Kennedy-2

Noise Blanker Wish List.

Greetings Folks,

An "Evasive" noise blanker is on my wish list. This is the system where the
noise blanker receives noise from "out of band" and none of its circuits
(except for its input "tap off" and the IF Gate) are in the main signal
path. Best done when you can tune the noise blanker receiver a little to
avoid strong out of band signals (ie evasive). The result is that your
crosstown "friend" at S9++ and 1 kc up does not "key" the noise blanker. The
idea has been around for a long time, Collins used it but they picked up
noise at low VHF. Bit more complex but it really pays off I've found.

73,

Geoff.

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Stewart Baker

Re: Noise Blanker Wish List.

The Trio TS180S had this scheme of noise blanker as well.

73
Stewart G3RXQ

On Fri, 11 Feb 2005 08:55:13 -0000, Geoffrey Mackenzie-Kennedy wrote:

> Greetings Folks,
>
> An "Evasive" noise blanker is on my wish list. This is the system where the
> noise blanker receives noise from "out of band" and none of its circuits
> (except for its input "tap off" and the IF Gate) are in the main signal
> path. Best done when you can tune the noise blanker receiver a little to
> avoid strong out of band signals (ie evasive). The result is that your
> crosstown "friend" at S9++ and 1 kc up does not "key" the noise blanker. The
> idea has been around for a long time, Collins used it but they picked up
> noise at low VHF. Bit more complex but it really pays off I've found.
>
> 73,
>
> Geoff.
>
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> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
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>
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> Elecraft web page: http://www.elecraft.com

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n6wg

Re: Noise Blanker Wish List.

In reply to this post by Geoffrey Mackenzie-Kennedy-2

Geoff
That's the way the NB in my old Kenwood TS180 worked.
It has an 8 MHz 1st IF, and the NB pickoff is before the 8 MHz crystal
filter, as I recall. The NB is tunable with a front panel control to
allow you to move away from an interfering signal.
73, Bob N6WG

-------------- Original message --------------

Geoffrey Mackenzie-Kennedy-2

Re: Noise Blanker Wish List.

In reply to this post by Stewart Baker

Thanks for the comment Stewart. I suspect that the advent of DSP has put the
very effective Evasive Noise Blanking technique in the background, perhaps
cost. I would like to try eliminating the IF Gate, and have the blanker's
output switch off/on the LO drive to one of the 'H' mixers in the homegrown
receiver. This should be quite easy as 'logic' circuitry provides the 50%
duty cycle square wave LO to each mixer, but I would probably get myself in
a muddle with timing etc. Worth trying though as then there would be no
blanking circuitry in the direct signal path, other than the input which is
well isolated..

73,
Geoff
GM4ESD

----- Original Message -----
From: "Stewart Baker" <[hidden email]>
To: "Geoffrey Mackenzie-Kennedy" <[hidden email]>; "Elecraft
Discussion List" <[hidden email]>
Sent: Friday, February 11, 2005 9:27 AM
Subject: Re: [Elecraft] Noise Blanker Wish List.

The Trio TS180S had this scheme of noise blanker as well.

73
Stewart G3RXQ

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Stewart Baker

Re: Noise Blanker Wish List.

Geoff,

I think that you hit the nail on the head 'cost'.
There are lots of nice things one could do to the K2 such as a better noise
blanker, but only a few people would want to pay for them.
Good luck with your homebrew extensions.

73
Stewart G3RXQ

On Sat, 12 Feb 2005 15:32:10 -0000, Geoffrey Mackenzie-Kennedy wrote:

> Thanks for the comment Stewart. I suspect that the advent of DSP has put the
>
> very effective Evasive Noise Blanking technique in the background, perhaps
> cost. I would like to try eliminating the IF Gate, and have the blanker's
> output switch off/on the LO drive to one of the 'H' mixers in the homegrown
> receiver. This should be quite easy as 'logic' circuitry provides the 50%
> duty cycle square wave LO to each mixer, but I would probably get myself in
> a muddle with timing etc. Worth trying though as then there would be no
> blanking circuitry in the direct signal path, other than the input which is
> well isolated..
>
> 73,
> Geoff
> GM4ESD
>
> ----- Original Message -----
> From: "Stewart Baker" <[hidden email]>
> To: "Geoffrey Mackenzie-Kennedy" <[hidden email]> "Elecraft
> Discussion List" <[hidden email]>
> Sent: Friday, February 11, 2005 9:27 AM
> Subject: Re: [Elecraft] Noise Blanker Wish List.
>
>
> The Trio TS180S had this scheme of noise blanker as well.
>
> 73
> Stewart G3RXQ