[R-390] OT: R-2368A/URR or RF-590 Noise Blanker manual (suppliment)

[Shoppa, Tim]

I cannot help you with the original Harris NB, but some words of wisdom regarding noise blankers:

Most are built to suppress ignition noise or (especially ham rigs of the late 70's) the Russian Woodpecker. The best are surprisingly sophisticated and they have an independent IF chain with "fast" filters, so that the noise pulse can be identified and blanked before the noise even hits the regular IF chain.

This is a fundamentally different kind of noise than the broadband whine generated by poorly designed switching power supplies in computers and flat screen TV's and other modern consumer products.

There are some DSP-type audio chains available (advertised in the ham magazines) that can be surprisingly effective against the broadband whine common today.

A small side point: take a battery operated radio, and listen to the noise while you turn off the master circuit breaker in your house AC panel. If the noise goes away, it was coming from your own house. You'd be surprised. After this you start going around the neighborhood with the battery radio, most especially looking for power poles.

Tim N3QE

-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net] On Behalf Of Jim Green
Sent: Thursday, May 06, 2010 1:53 PM
To: R-390 at mailman.qth.net
Subject: [R-390] OT: R-2368A/URR or RF-590 Noise Blanker manual (suppliment)

Sorry about the off topic subject, I've tried everything I can to  
find a place that would be appropriate to find the answer.

I have a Harris R-2368A/URR receiver. I have the complete service  
manual as well. Alas the receiver does not have the optional noise  
blanker installed. I live in a noisy neighborhood and would like to  
build a noise blanker for this receiver. I have collected many online  
articles and contacts that could help me to do this, but I would  
prefer to have a more exact, or equivalent circuit that Harris  
designed for this receiver. As far as I know Harris no longer  
supports this receiver and even if they did I wouldn't be able to  
afford even 10% of the $2,000.00 price tag for the optional noise  
blanker.

The information given in the manual about the optional noise blanker is:

Part = RF-597A
Name =  Noise Blanker
Part No. 10215-6800
Description = The Noise Blanker removes impulse type noise from the  
received signals. Adjusts automatically to received signal level  
changes.
Publication No. = 10215-0019 (supplement)

Does anyone have or know where I can get a copy of the noise blanker  
publication? Better yet, does anyone know where I can find an  
original Harris RF-597A noise blanker? These were the same in both  
the R-2368A/URR and the RF-590.

73

Jim (KG9MM)
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