[RFI] RFI Digest, Vol 119, Issue 35

George ve3yv at pathcom.com
Sun Dec 30 15:12:28 EST 2012

For a diagram of how to hook up an ANC4 or MFJ1025/1026, see:
Should work with any rig having a separate RX jack and eliminates the need
for TR switching in the noise canceller box.  

The external noise antenna is critical for effectiveness - the MFJ whip
antenna is not enough.  Also, as noted, it's only good for one source.  Like
peeling off the layers of an onion, some crying may result.

Noise is just one of the joys of centre of the city DXing...  

73, George VE3YV / K8HI

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


Message: 4
Date: Sat, 29 Dec 2012 16:46:08 -0800
From: Jim Brown <jim at audiosystemsgroup.com>
To: rfi at contesting.com
Subject: Re: [RFI] Damned Amtrak
Message-ID: <50DF8ED0.4070105 at audiosystemsgroup.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 12/29/2012 1:25 PM, dalej wrote:
> You might consider a Timewave ANC-4 noise canx device.

Perhaps -- the MAJOR problem with these boxes is that the RF detection
circuit that does T-R switching is a NASTY key click generator that will
make your neighbor hams very unhappy. An easy cure for this is to put the
noise canceller in the RX antenna input, if you have one.

The MFJ equivalent is supposed to be better at noise cancelling, but I
haven't seen one and don't know about clicks. And, of course, be aware of
their QC problems and prepared to fix cold solder joints.

As Dale has mentioned, the key to these working well is having a noise sense
antenna that is as close as possible to the noise. You want the ratio of
"noise" to desired signal on that "sense" antenna to be as high as possible
so that you cancel more noise and less desired signal.  :)

73, Jim K9YC

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