Hi Dave,
Fantastic, and you got plenty close before switching to VHF. I typically
switch to VHF when I’m typically within 0.1 or 0.2 miles from the faulty
pole. I have sometimes heard power line noise 0.75 miles away up on 135MHz
using my portable 4 element 2 meter Yagi in which I have lengthened the tip
of each element about 1.4 inches using alligator clips to maintain a proper
pattern on 135 MHz where my VHF AM radio operates.
Thanks again for sharing.
73,
Don wd8dsb
On Sat, Jun 19, 2021 at 5:19 PM Dave Hachadorian <k6ll.dave@gmail.com>
wrote:
> Hi Don,
>
> The pole is 2.1 miles from my QTH.
>
> When I tried unsuccessfully to use the flag in the end-game, it turned out
> that I was only about 100 yards from the offending pole. I wanted to remove
> the preamp, but didn’t have the correct connectors to bypass it, so I had
> to leave the preamp in and add the attenuator. I didn’t think of using the
> flag at a higher HF frequency. I’ll keep that in mind for next time.
>
> Now that I have one success under my belt, it has given me hope and
> confidence that I can lower my noise floor even more!
>
> Thanks for your work in designing the flag, and for all of your postings
> on the reflector!
>
> 73
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
> *From:* Don Kirk
> *Sent:* Saturday, June 19, 2021 1:53 PM
> *To:* Dave Hachadorian
> *Cc:* reflector RFI
> *Subject:* Re: [RFI] Noise located and FIXED
>
> Hi Dave,
>
> Thanks for sharing and great story. How far from your QTH was the bad
> pole and how close to the pole when you had to switch to VHF?
>
> The more you use the portable flag the more comfortable you will become
> with how it works. You probably could have moved up to 14 or 21 MHz as you
> approached the pole using the portable flag (if you did not do this) as an
> example to get closer before having to switch to VHF. You mentioned using
> 30 db attenuation with the portable flag when you got closer to the pole
> and wonder if you also removed the preamp at some point?
>
> I do use the null on the portable flag but if I notice slight differences
> in direction between the peak and null I then trust the peak because nearby
> objects can alter the backside of the antennas pattern (might create a
> minor lobe where the null should be as an example and then you will notice
> 2 nulls, one on each side of the minor lobe that has developed). I really
> only notice this when standing very close to my house as an example (like
> 10 feet from the house). I have never found the main peak to be altered,
> and it’s therefore very trustworthy. I normally just stand out on the
> sidewalk in front of homes or out at the street curb and this really works
> well (peak and null work great).
>
> 73,
> Don Kirk (wd8dsb)
>
>
> On Sat, Jun 19, 2021 at 4:09 PM Dave Hachadorian <k6ll.dave@gmail.com>
> wrote:
>
>> About 10 days ago, a big noise started up on 80 meters, S9+15 dB with the
>> preamp off and attenuator off on my K3. The noise was present 24/7.
>>
>> Today I found the source, reported it, and two hours later, it is fixed!
>> Here was my tracking procedure.
>>
>> I started out with the portable flag antenna from March 2021 QST. The
>> flag fed a 20 dB HF preamp that I have had for years (ARR P1-30/20VD). The
>> preamp fed a Tecsun PL-660 Shortwave Receiver. I could hear the noise
>> easily on 80 meters with that combination, and took a bearing on the null.
>> I drove in the direction of the null, and stopped to take additional
>> bearings along the way, which told me that I was going in the correct
>> direction. The noise kept getting louder.
>>
>> Finally I got to a point where the noise was so loud on 80, even with a
>> homemade 30 dB attenuator inserted in the line, that the flag was not
>> giving me a good null. At that point, I switched to my old 2 Meter mobile
>> rig, which can receive on AM mode (Kenwood TM-261A), and for an antenna I
>> used the back four elements of an old 2 Meter 11 element beam, lashed to a
>> broomstick. Unfortunately, the S-Meter on the TM-261A does not work in AM
>> Mode, but I used the loudness of the audio signal to guide me. I soon came
>> to a pole where I could hear audible arcing with just my ear, without even
>> listening to a radio! At that point I hooked a Tiny SA Spectrum Analyzer
>> to the 2 Meter antenna, just to use it as an S-Meter. The Tiny SA is not
>> very sensitive, but it showed a very raspy signal of –80 dBm all across the
>> 2 Meter Band when the beam was pointed toward the pole.
>>
>> I called the power company and reported it as “arcing on a pole.” I
>> didn’t mention anything about radio noise. They gave me an incident
>> number, and said they would get on it. Two hours later, I happened to look
>> at Panadapter on the home station, and saw the noise disappear! I zoomed
>> back to the pole, and talked to the lineman, who told me that it was a bad
>> connection. He said he was going to put in an order to replace all of the
>> hardware on that pole, which includes two transformers, lightning
>> arrestors, and some other stuff. A picture of the pole is attached, unless
>> the reflector strips off attachments. Incidentally, this pole is 2.1 miles
>> from my house.
>>
>> Many thanks to all of the contributors on this reflector who have
>> provided a valuable education on noise locating!
>>
>> Dave Hachadorian, K6LL
>> Yuma, AZ
>>
>>
>>
>> _______________________________________________
>> RFI mailing list
>> RFI@contesting.com
>> http://lists.contesting.com/mailman/listinfo/rfi
>>
>
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|