[RFI] Using an SDR to locate RFI

Leigh Sedgwick bipi at comcast.net
Mon Dec 12 14:08:08 EST 2016

I have used my SDRIQ with my MS Surface in the car.  The SDRIQ is a nice
compact box 4.5 in X 4 in X 1 in (W X D X H) powered by the USB port.  I use
Spectravue software and a National RF, Inc HFDF handheld loop.


-----Original Message-----
From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of Frank N. Haas
Sent: Monday, December 12, 2016 10:26
To: Don Kirk <wd8dsb at gmail.com>
Cc: rfi at contesting.com
Subject: Re: [RFI] Using an SDR to locate RFI


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
> 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
RFI mailing list
RFI at contesting.com

More information about the RFI mailing list