[RFI] Using the SDRPlay receiver for RFI for searches

[Tom Thompson]

Hi Frank,

I have used SDR Console and HDSDR and decided that HDSDR is the best app 
for me.  It takes some time to learn, however.

  I have recently been tracking down some CenturyLink modem uplink 
leakage that is present from 3.75 MHz to 5.1 MHz.  The antenna system, 
which consists of a high impedance preamp and a 3 ft. whip, is really 
important since it is not tuned and I don't have a narrow band antenna 
factor to worry about.  The down side of that kind of a set up is that 
SDRPlay may become overloaded since the system is looking wide band.  To 
overcome that, I have built some small band pass filters that I insert 
between the high impedance preamp and the SDRPlay receiver.  These 
filters pass only the spectrum that I am interested in.  So far I have 
filters for 80m, 40m, 20m, and the Century link spectrum.  If I am not 
near any strong broadcast stations, the filters are not needed.  Also, 
the wide spectrum of SDRPlay allows me to see what I am really tracking 
and not to get confused by other noise sources in the area.

I always use VHF or UHF with a Yagi to track power line noise.

73,   Tom   W0IVJ

On 2/9/2016 7:06 AM, Frank N. Haas KB4T wrote:
>
> Tom:  What software are you using to operate the SDRPlay? I have used 
> SDRSharp & HDSDR. I have used these mobile only.
>
> The receiver hears very well. HDSDR is stable but a bit challenging to 
> use. SDRSharp is quirky and occasionally exhibits some strange behavior.
>
> As a general purpose receiver the SDRPlay is very handy with its wide 
> range, excellent sensitivity and selectivity. I do mostly power line 
> interference searches. Unfortunately I find the SDRPlay unusable for 
> power line interference searches. The spikes never appear on the 
> display and the two software packages I've tried are optimized to 
> eliminate noise and are amazingly effective at ignoring power line noise.
>
> Of course, if the interference you seek is more like a conventional 
> signal, the SDRPlay and either of these two software packages give a 
> highly informative display and great receive capability. In close, an 
> attenuator is needed to manage signal levels to get usable signal 
> strength indications.
>
> Has anyone had any success using an SDR for power line noise searches?
>
> Frank N Haas KB4T
> Utility Interference Investigator
> Florida
>
> On Feb 5, 2016 11:48 PM, "Tom Thompson" <w0ivj at tomthompson.com 
> <mailto:w0ivj at tomthompson.com>> wrote:
>
>     Tony,
>
>     I have been using an SDRPlay ($150 from HRO) and a small laptop or
>     tablet running HDSDR (free).  If you build or buy a high impedance
>     preamp, you can use a 3 ft. whip with a magmount and you have a
>     wide band set up that will show you the spectrum of the RFI from
>     your car.  When you get closer you can DF it with a loop.  I have
>     found that being able to look at the whole spectrum is really
>     helpful in tracking down the RFI because you can really keep track
>     of the RFI signature.  The SDRPlay allows you to look at about 5
>     MHz of spectrum from 100 kHz to about 2 GHz.
>
>     Tom   W0IVJ
>
>     On 2/5/2016 7:52 PM, Tony wrote:
>
>         All:
>
>         I've had an RFI issue coming from a specific direction for
>         several years. It's a unique noise that appears on several HF
>         bands which is usually a couple of S-units above the noise
>         i.e., just enough to cover weak signals in that direction.
>
>         I thought I could use a VHF / UHF radio to pinpoint the
>         source, but I'm not able to hear it on my all-mode VHF/UHF
>         home station with Yagi antennas.
>
>         The ideal setup might be a portable HF radio which can tune
>         the same frequencies that are susceptible to the noise.
>         Something small enough to carry and use with a portable HF loop.
>
>         I was thinking about a Kenwood TH-F6A that has HF SSB / CW
>         coverage, but I'm told the receiver isn't very sensitive; even
>         with an external antenna.
>
>         Any suggestions?
>
>         Thanks
>
>         Tony
>
>
>
>
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