[RFI] 160m & 80m RFI issues requesting ideas for ANC4 sense antenna to cancell out local noise

Tom Thompson w0ivj at tomthompson.com
Sun Nov 1 15:30:46 EST 2015

Hi All,

The SDRPlay radio ($150 from HRO) coupled with HDSDR ( free) makes an 
excellent tool for tracking RFI.

  I recently was called in to track the source of some 80m 
interference.  This RFI was about 20 dB above the band noise from about 
3775 kHz to about 5200 kHz.  It turned out to be VDSL2 leakage from the 
local telephone company deploying wide band internet. VDSL2 has an 
uplink band that matches that frequency range exactly.

W0QE and I worked together to develop a wide band, high impedance preamp 
that we coupled with a small, mag mounted vertical.  We were able to 
drive around the neighborhood and locate several VDSL2 leakages as well 
as several other sources of RFI.

Tom   W0IVJ

On 11/1/2015 12:55 PM, Kenneth G. Gordon wrote:
> On 1 Nov 2015 at 10:09, Joe Wolfe wrote:
>> The noise I have is a very loud and strong White Noise.
> Ah, yes. The same sort of crap we are experiencing around here. After at
> least two years of work here, we have finally established that it is a
> mish-mash of many, many other sources all jammed together, and not any
> one single source. By elminating the stronger local sources, the White Noise,
> is vastly diminished.
> Mine here was 10 to 20 db over S-9 on 80 until we eliminated a single source
> that was within 4 blocks of my station. At that time, the White Noise level
> dropped to S-4 to S-5 most of the time.
> Even so, I still have multiple sources scattered around the town near me,
> including one at our local high-school.
>>   I am hoping the
>> ANC-4 will help with that.
> Well, it probably will, if you get a good enough sense antenna and spend
> enough time getting to know how to operate it. Effective use of that method
> requires some finesse.
>>   The noise is definitely not in my house..I have
>> killed the power to the whole house and the noise is still present. Handhelds',
>> etc.  have not been able to pinpoint any source.
> You need a directional antenna, at the very least...
>> So..I am reading this thread very closely to see if any new ideas pop up
>> that might help steer me in the right direction!
> Joe:
> I wish I was closer to you. I would help you DF this garbage.
> But as WX5L says, I too think your time would be far more efficiently used in
> trying to track this stuff down than trying to "cover it up".
> Also, as another member says, using any receiver you use to try to track it
> down should be set to AM, rather than to CW or SSB, as this will make your
> job a bit easier by making it much easier to recognize the differences in the
> sounds of the noise.
> Ken W7EKB
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