[RFI] Power Line Noise in Indonesia

[Pete Smith]

At 02:07 PM 7/20/2004, Tom Rauch wrote:
>I haven't looked at what you are talking about, but I expect
>it is a tunable noise receiver that you place on a clear
>frequency with only noise, and the receiver drives a blanker
>for signals in the main receiver system.
>
>If so, it cannot be a phased system or a noise subtraction
>system. It has to be a blanker.
>
>The problem is it would be a level threshold trigger for a
>gate that turns of the receiver system. In effect this
>punches a hole in the signal.
>
>It is useful only for short sharp pulses like ignition,
>ringing noises or multiple noises cannot blanked without
>degrading desired signals. The noise duty cycle has to be
>low, and peaks sharply defined.
>
>I did suggest to MFJ that I would design one if they built
>it, but it never happened. I did have just such a system in
>my old diesel truck, to blank sharp pulses from the injector
>solenoids. I'm not sue how it would work with power line
>noise.

As I recall, this is what Collins offered at one point as an add-on for the 
KWM2A -- it attached to the underside of the hatch in the cabinet and, from 
memory, operated at ~46 MHz.  We had one of these radios in the old State 
Department club station next to the elevator motors of a 9-story building 
in downtown DC.  I don't recall that the blanker was particularly effective 
on most of the urban noise environment.


73, Pete N4ZR
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