[RFI] Using an SDR to locate RFI

Frank N. Haas KB4T utility.rfi.pro at gmail.com
Mon Dec 12 13:25:42 EST 2016


On Dec 12, 2016 1:24 PM, "Don Kirk" <wd8dsb at gmail.com> wrote:

> Hi Frank,
> You and I think exactly alike regarding not being interested in what the
> source is when trying to track it down, but rather locating the source
> first (what property it's emanating from), and then figuring out what the
> source is.
> I just read your other posting, and I think what you are saying is that
> you want an SDR setup that's convenient for mobile use.  I don't think
> you're saying the SDR technology does not display what you want, but rather
> the hardware is cumbersome from a mobile setup?  Is this correct?
> Don
> On Mon, Dec 12, 2016 at 1:14 PM, Frank N. Haas KB4T <
> utility.rfi.pro at gmail.com> wrote:
>> Don:
>> Most Power Line arcing as well as most other interference sources produce
>> a consistent, non-sinusoidal or barely varying signal strength indication
>> on the IC-7000. Clearly the hysteresis of the AGC circuits average the
>> signal strength indication well. Yet the signal strength indication
>> effectively rises and falls nicely in step with my approach and departure
>> as I pass a true RFI source.
>> The 7000 does not have a true spectrum scope like the 756Pro receivers.
>> There is a spectrum scan feature but it is essentially useless for RFI
>> location...in my opinion. I'm no so concerned with the frequency of the
>> interference source's components. Instead I'm concerned with the
>> frequencies affected by the source. There is a difference. I focus on
>> locating the source, not what the source is composed of.
>> 73,
>> Frank N. Haas KB4T
>> Utility Interference Investigator
>> Florida
>> On Mon, Dec 12, 2016 at 12:46 PM, Don Kirk <wd8dsb at gmail.com> wrote:
>>> Rank,
>>> Another comment.  It looks like the peaks are approximately every 4000
>>> hertz in your display which would make it look more like noise from a
>>> variable speed drive or similar source, and not arcing on a power line.  If
>>> that's the case, then my SDR receiver as well as analog HF rig definitely
>>> see the peaks and valleys of such interference.
>>> Don (wd8dsb)
>>> On Mon, Dec 12, 2016 at 12:38 PM, Don Kirk <wd8dsb at gmail.com> wrote:
>>>> HI Frank,
>>>> One has to ask if the display you see on the IC-7000 is real?  As an
>>>> example, if it were real then as you tune the frequency up and down the
>>>> band on the IC-7000 you should see peaks and valleys in the S meter
>>>> reading, but that's not what I typically see when observing power line
>>>> arcing (or light dimmer interference which mimics power line arcing quite
>>>> well as it provides a transient during both the positive and negative
>>>> portion of the sine wave).  I typically just see a rise in the overall
>>>> noise floor regardless of what frequency I'm on within a band both on my
>>>> old Kenwood TS-180s analog HF rig, or on an SDR receiver (but next time I
>>>> experience powerline noise I will be more observant, and I will simulate
>>>> that tonight with a light dimmer I have at home).
>>>> All of my experience is down on 160 meters, but suspect what I see down
>>>> there would be similar on other bands????
>>>> Maybe if you see peaks and valleys as you tune across the band we could
>>>> theorize that more energy is effectively radiated by the power lines on
>>>> frequencies where they are resonant, but I don't think that's the case
>>>> based on how often the peaks and valleys are occurring on your display.
>>>> What do you think about my above comments?
>>>> P.S. you raise an interesting issue/topic that I will pay more
>>>> attention to the next time I encounter power line arcing.
>>>> Don (wd8dsb)
>>>> On Mon, Dec 12, 2016 at 11:19 AM, Frank N. Haas KB4T <
>>>> utility.rfi.pro at gmail.com> wrote:
>>>>> For the last several months, I've been trying to use an SDRPlay SDR
>>>>> Receiver with 3 different software packages as a tool for locating
>>>>> arcing
>>>>> and other forms of interference to the HF and VHF spectrum. I have
>>>>> virtually nothing to show for the effort.
>>>>> For over a decade, I've been using an ICOM IC-7000 mounted in my work
>>>>> vehicle with a Hi-Q 4/80 HF screwdriver antenna, a VHF 3 dB base loaded
>>>>> mobile antenna, a 5 dB center loaded UHF mobile antenna and an antenna
>>>>> switch to effectively drive to within 1 pole or 1 structure of the
>>>>> source.
>>>>> The system has served me well and made my (nearly daily) interference
>>>>> location work efficient and easy.
>>>>> The IC-7000 is long in the tooth. While I enjoy cashing the Social
>>>>> Security
>>>>> checks for the rig, I admit I'm spoiled by the enormously informative
>>>>> spectral displays provided by SDRs. It's time to retire the 7000 and
>>>>> install something new. The SDRs seem like the perfect, reasonably
>>>>> priced
>>>>> solution. Yet the SDRs are so efficient at masking noise that it's
>>>>> nearly
>>>>> impossible to use one as a locating tool.
>>>>> But my experience is limited to the SDRPlay. I chose the SDRPlay
>>>>> because of
>>>>> its frequency coverage. I've tried SDRUno, SDR Sharp and HDSDR software
>>>>> packages. I've spent hours experimenting with the configuration of
>>>>> each of
>>>>> these software options and have not been able to find a setup that
>>>>> effectively, consistently and clearly displays arcing interference.
>>>>> What
>>>>> I'm looking for is the type of display one sees on an ICOM IC-756-II or
>>>>> -III spectrum display. Look me up on QRZ (KB4T) to see a picture of
>>>>> what I
>>>>> seek.
>>>>> I've tried an Anritsu and an HP Spectrum Analyzer and they lack the
>>>>> sensitivity or the mounting practicality to do what I want.
>>>>> There are many other SDRs out there. WinRadio, AirSpy and a boat load
>>>>> of
>>>>> other makes and models. HAS ANYONE ACHIEVED ANY MEASURE OF SUCCESS
>>>>> getting
>>>>> one of these smart boxes to provide a useful spectral display of arcing
>>>>> interference? If so, please share with this group!!!
>>>>> Thank you!
>>>>> Frank N. Haas KB4T
>>>>> Utility Interference Investigator
>>>>> Florida
>>>>> _______________________________________________
>>>>> RFI mailing list
>>>>> RFI at contesting.com
>>>>> http://lists.contesting.com/mailman/listinfo/rfi
>> --
>> Frank N. Haas KB4T
>> Utility Interference Investigator
>> Florida

More information about the RFI mailing list