Good work Alan!
Going to keep this email to use as a reference.
See you at the Visalia DX Convention.
Ray,
N6VR
On Wed, Feb 28, 2018 at 10:40 AM, Dave Cole (NK7Z) <dave@nk7z.net> wrote:
> Well thought out process, and it works!!! Thanks for the image, it is up
> under Infrastructure now.
>
> 73s and thanks,
> Dave
> NK7Z
> https://www.nk7z.net
>
>
> On 02/28/2018 09:23 AM, Alan Higbie wrote:
>
>> In October 2017 I started to observe some spitting type broadband RFI
>> noise
>> spikes. Within a week or so noticed that when outside temperature cooled
>> in
>> evening the noise spikes would become constant. Then noticed high winds
>> would cause more spikes in noise level. Eventually the RFI became
>> constant.
>>
>>
>> This noise caused my normal noise floor (on P3 scope) of about -120 dBm to
>> increase by 30 dBm to -90 dBm. The noise responded well to the NB on K3 -
>> but using the NB during contests also resulted in IM products and made
>> communications difficult.
>>
>>
>> *These are steps taken*:
>>
>>
>> 1. Cut power at the panel of our house - K3 on battery power. No change.
>> So coming from outside. Had neighbors cut their power too. Eliminated
>> them
>> as source.
>>
>>
>> 2. Used National RF Vector Gun w/ loop - to DF the source. Best used to
>> null off ends of loop. Initially hooked loop to Tecsun PL 660 set on 20
>> meters; then connect DF loop to KX2, then eventually set the P3 to run
>> ALONE as SDR receiver on 14.020 MHz (see page 25 of P3 Manual) (also
>> Instructions found at: http://www.g3tct.co.uk/P3.html ). Connected the
>> DF
>> loop to I.F. Input of the P3. Ran on battery and carried around.
>>
>>
>> 3. The P3 connected to the DF loop tuned to 14.020 showed noise signal
>> level only about 12 dB down from the strength shown on P3 when connected
>> to
>> 2 el. 40 mtr. yagi.
>>
>> But using that portable set up allowed for making sure I was tracking same
>> noise signal that was bothering me in the shack.
>>
>>
>> 4. Before getting zero'ed in on the offending pole(s) - - it dawned on me
>> to try pinpointing noise source by carefully peaking the beam. The P3
>> (with SVGA) may be configured to display signal strength in 1 dB
>> increments
>> (spaced about 1 inch vertically) !! And, I now have a digital readout on
>> my rotator indicator (Green Heron). I spent about 20 minutes slowly going
>> back and forth. Finally determined that noise source peaked at 65 degrees
>> from my antenna.
>>
>>
>> 5. Then, walked with P3 and National RF Vector Gun DF loop roughly along
>> the 65 degree line away from my house. Eventually the signal got stronger
>> and stronger. This was 1/3 mile away.
>>
>>
>> 6. Then borrowed a friend's FT 817. With that set for 220 MHz AM and a 7
>> element yagi (Arrow 220-7) - located which pole I thought it was. But
>> wasn't completely sure - because the QRN/RFI signal was so strong -
>> thought
>> it was one of two poles close to each other. I should have inserted step
>> attenuator between beam and FT-817.
>>
>>
>> 7. Having narrowed it down to two poles, I emailed the Colorado Springs
>> Electric Utility. Mentioned that my FCC licensed station was now
>> essentially off the air because of RFI from the arcing and the utility's
>> power leak. And mentioned that this was coming from 1/4 mile away. I
>> sent
>> along photos of the poles - with close ups showing pole numbers. I also
>> sent a map and aerial photo (from Google Maps) showing my house, the 65
>> degree beam heading, distance, location of poles, handwritten pole
>> numbers,
>> etc.
>>
>>
>> I went to the area at night - using binoculars - I looked for visible
>> arcing - but couldn't see any.
>>
>>
>> 8. A utility engineer emailed back - and he suggested we meet at the
>> site.
>> But I suggested we first meet at my house. He brought a lineman. I showed
>> them my shack and especially how the noise looked on the P3 scope - and
>> demonstrated what it should look like by flipping the SteppIR 180 degrees.
>> They could SEE my problem.
>>
>>
>> 9. The engineer brought along the utility's Radar Engineers RFI locator
>> M330 !! (Yes, I told him I was happy to see they had followed my
>> suggestion
>> of 12 years earlier - about buying one) He also brought along a Radar
>> Engineers MODEL 250 Parabolic Pinpointer Ultrasonic Locator. (another
>> suggestion) Note: This felt like I had dropped a hint about what I wanted
>> from Santa !!
>>
>>
>> 10. Triangulating around the immediate area - using that nifty gear - the
>> engineer confirmed which pole supported the noise source.
>>
>>
>> 11. The pole in question carried 7200 volt lines at lower level and 34,500
>> volt lines above that.
>>
>>
>> 12. On the first day - the lineman went up and wiggled and tightened stuff
>> on the 7200 lines But that made no difference. Being by himself - with a
>> bucket truck which couldn't reach the upper wires - they suspended the
>> operation for the day.
>>
>>
>> 13. A week or so later - the engineer came back with a larger bucket
>> truck
>> / a crew of two lineman - and a foreman.
>>
>>
>> 14. They couldn't quite zero in on exact source on the pole. But they
>> started by de-energizing the 34,500 lines. They sent me home to check my
>> noise in the shack. Still the same. None the less they tightened and
>> replaced hardware on those lines
>>
>>
>> 15. The linemen came back down lower to the 7200 volt lines. They
>> wiggled,
>> tightened and disconnected stuff - until eventually they made the noise
>> stop on engineer’s RFI locator. The source of this noise was a lightning
>> arrester which was failing.
>>
>>
>> 16. They *replaced lightning arrestor* and the noise was gone on their RFI
>> locator - - but to be sure, they had me drive home to check noise level in
>> my shack - and yes, the particular noise had been eliminated
>>
>>
>> 17. The replacement of the defective lightning arrestor reduced my noise
>> floor by 30 dBm (from approx. -90 dBm back down to -120 dBm.)
>>
>>
>> 73, Alan K0AV
>>
>> Colorado Springs
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--
Ray,
N6VR
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