[600MRG] GW4ALG Nosie Canceller (was Re: QEX Noise Canceller)

[mbdittmar at comcast.net]

Hi - 

I built Lloyd Butler VK5BR's phase-shifting noise canceller for LF/MF in order to try and combat the massive line noise I have every night between 440 - 510 khz. The schematic is at: 

http://users.tpg.com.au/users/ldbutler/LFNoiseCancel.htm 

It uses an LC network front-end to perform the phase shift. It's a simple circuit and quick to build. 

Anyway since my noise is coming in thru the line ( coming INTO my house over the power line ) I just used a wire a few feet long in the shack for my noise antenna. 

The system works GREAT. I can completely null out my problem noise on 630 meters ! It's amazing how well it works. As usual YMMV. 

73 Mark AB0CW / WG2XNI 


----- Original Message -----

From: "Warren K2ORS" <k2ors at verizon.net> 
To: 600mrg at w7ekb.com 
Sent: Monday, March 30, 2015 2:30:08 PM 
Subject: [600MRG] GW4ALG Nosie Canceller (was Re: QEX Noise Canceller) 

See Steve GW4ALG noise canceller: 
http://www.alg.myzen.co.uk/radio/136/noise_can.htm 

73 Warren 

On 3/30/2015 3:18 PM, Brian Pease wrote: 
> One of the 2 antennas must have a better s/n than the other, otherwise 
> the desired signal will be cancelled out with the noise. Using an 
> identical "noise" antenna helps keep the noise waveform the same for 
> better cancellation. 
> 
> On 3/30/2015 2:59 PM, Kenneth G. Gordon wrote: 
>> On 30 Mar 2015 at 17:59, Marshall Cross wrote: 
>> 
>>> Then why not use the same antenna with a splitter? 
>> Hmmm....that makes sense...sort of....to me, but I am most certainly 
>> not an 
>> expert on such things either. Perhaps some separation between the 
>> antennas, even if small, is needed in order to achieve a necessary phase 
>> difference. I may ask Mike about it. 
>> 
>> BTW, I was wrong on the value of the reduction in noise level that Mike 
>> achieved with his unit: instead of a 25 dB reduction in noise, it was 
>> actually 
>> a measured 31 dB reduction in noise. 
>> 
>> I thought that was.....adequate... ;-( 
>> 

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