[RFI] Help finding a source

[Bill Steffey]

Hi,

mfj still sells a #852   which is nothing more than a VHF am receiver 
with a dipole integrated onto the case.. ..  Bought one new 14 years ago 
   then found another at a hamfest for 40$ .

After showing Commonwealth Edison rfi guy my panadapter and the beam 
heading stuff, I took him into the neighbors back yard with this little 
box with a meter & headphones. Straight to the bad pole. He said it 
worked better than the Radar Engineers equipment ...( not quite) ....and 
at that price his boss could get a few MFJs rather than passing around 
the expensive boxes... at least till need was indicated.  For powerline 
noise it is nothing but an aircraft AM receiver with a dipole ...which 
you retract for attenuation as you approach the suspect.  WORKS 
GREAT....   They sell the same meter with a beam for more money,,,

https://www.mfjenterprises.com/Product.php?productid=MFJ-852



On 12/5/2019 4:24 AM, Don Kirk wrote:
> Hi Michael,
>
> You mentioned three discharges per half cycle, but looks like it would be
> three discharges every other half cycle (if it is indeed power line
> equipment) since the period between the groups of 3 is around 16.7ms, not
> 8.3 ms.
>
> Don (wd8dsb)
>
> On Wed, Dec 4, 2019 at 7:19 PM Michael Martin <mike at rfiservices.com> wrote:
>
>> your noise is caused by loose hardware on the power line equipment.
>> the three spikes you see per group represent three discharges per half
>> cycle
>>
>> ⁣Get BlueMail for Android ​
>>
>> On Dec 4, 2019, 5:07 PM, at 5:07 PM, David Eckhardt <davearea51a at gmail.com>
>> wrote:
>>> I give up.        It's power line discharge.
>>> Dave - WØLEV
>>>
>>> On Wed, Dec 4, 2019 at 11:24 PM Michael Morgan <michael at aa5sh.com>
>>> wrote:
>>>
>>>> I was hoping to get some help identifying a potential source for some
>>> RFI
>>>> that started a few weeks ago.  I posted some pictures and audio clips
>>> from
>>>> 20 and 40 meters on my webpage.  Thought it may be easiest there I
>>> hope it
>>>> is ok.  https://www.aa5sh.com/?p=328
>>>>
>>>> I tried to get some screenshots from my 7610.  On 20M the Noise
>>> Blanker
>>>> does  a decent job of removing the noise but on 40M it is a bit two
>>> random.
>>>> I have tried turning the main breaker off to my house and use a
>>> portable
>>>> radio (Recent RS-918) off a battery and the noise is still there.  I
>>> did
>>>> walk around my property and noticed no real differences.  The odd
>>> thing is
>>>> it's kind of random.  It has been going to 30 Mins or so and it just
>>>> stopped for a minute while I've been typing this email for a minute
>>> or so
>>>> then started back up.
>>>>
>>>> Then at lunch today I took a break and remoted home since I saw where
>>> 10M
>>>> was open and there was no noise for that 30-40 minutes.
>>>>
>>>> I appreciate any guidance you can provide.  In my years of radio
>>> anytime I
>>>> have had noise problems I have always been able to narrow it down to
>>>> wall-wart or battery charger.
>>>>
>>>> 73
>>>>
>>>> Michael, AA5SH
>>>> _______________________________________________
>>>> RFI mailing list
>>>> RFI at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/rfi
>>>>
>>> One very last try:  Copy to Word.  Eliminate image.  Copy test with no
>>> image.  Paste to email.  If this doesn't work, I give up:
>>>
>>> In your third image, the audio spectrum, the groups (first peak of
>>> first
>>> group to first peak of next group) is 17.5 ms.
>>>
>>>
>>>
>>> The period on one cycle at 60 Hz is 16.67 ms.  Very close.  The sound
>>> clip
>>> also sounds suspiciously like 60 Hz discharge from the power
>>> distribution
>>> somewhere in your vicinity.  I usually detect this at 120 Hz as the
>>> discharge occurs at both the + and - peaks of the sine wave.  But not
>>> in
>>> this case.  In the time domain, I also usually detect an exponentially
>>> decaying envelope for each discharge.  No so in this case.  But,
>>> considering the period and sound, I'd guess its due to power
>>> distribution
>>> discharge in you area.  Walk the power lines with your battery-powered
>>> radio.  When you find a pole that is particularly, kick the pole hard
>>> and
>>> observe any change in the character of the sound on your radio.  If no
>>> change, its not at that pole.  Continue searching.  Also, damp weather
>>> usually exacerbates the discharges as does dusty conditions.
>>>
>>>
>>>
>>> Dave - WØLEV
>>>
>>>
>>> --
>>>
>>> *Dave - WØLEV*
>>> *Just Let Darwin Work*
>>> *Just Think*
>>> _______________________________________________
>>> RFI mailing list
>>> RFI at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/rfi
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