Jim (WPA),
Respectfully, if you have not used an SDR for location you should give
it a try before you write it off.
I have everything you mentioned-- and more with my SDR setup... Almost
all SDR packages come with a built in O-Scope display of the audio one
is tuned to, all SDR packages allow one the ability to listen, and in
any mode, although I use AM 99.9% of the time. All SDRs gives me the
ability to see the RFI across MHz, to KHz of spectrum, this helps in
locating exactly what source I am looking for. I can move higher in
frequency as I approach with no changed in gear, just a different
antenna... Works like a champ to locate RFI.
I can see individual RFI sources drop and increase as I rotate the loop,
that lets me follow one single source. It's amazing to rotate the loop,
and watch the ONLY the RFI source I am looking for dip, while the others
are not dipped... I take a bearing, and it is just like the old days,
take a few more, then start looking at a map, then get closer, and use
the Yagi at 100 MHz, using the same radio...
How did we do DFing before SDR, a Yaesu FT-817ND, several different
sized loops, a Yagi, and maps, just the same as I use the SDR.
The SDR is tons faster. You should give it a try-- really! I have done
both methods extensively, and the SDR makes it a lot simpler and faster
for me. I still wander around with headphones on listening to the RFI,
I just get more data by looking at the SDR display which helps me in
locating RFI.
Dave
NK7Z
http://www.nk7z.net
On 09/25/2017 03:41 PM, JW via RFI wrote:
Well, maybe one's ears have gone bad limiting one's ability to note the noise
characteristics.
From the SDR spectrum displays I've seen one CANNOT note whether the carrier
is AC line modulated or not - just a pip showing on the screen..
Real definitive. I find an oscilloscope observing the AM detected output of the
receiver in the time domain to be more useful. I even use LINE TRIGGER to
verify it is AC line related.
Also, if you'll note, wideband arcing AC line sources simply cause an SDR's
baseline to rise across the entire viewing range and without actually LISTENING one
cannot know if the SDR is showing anomalous overload indications or broandand
impulse noise. .
Give me a device I can use my ear with any day of the week .. ...
(How did we ever DF noise sources before SDR burst onto the scene? To me, many
SDR aficionados are just looking for a 'mission' they can fill in this regard
and have little to no other exposure to DF techniques.)
de Jim WB5WPA,
From: Jim Brown <jim@audiosystemsgroup.com>
To: rfi@contesting.com
Sent: Monday, September 25, 2017 5:09 PM
Subject: Re: [RFI] Help Identifying RFI
On 9/25/2017 6:56 AM, JW via RFI wrote:
Massive overkill IMO to stress the need for an SDR to accomplish this task.
Not really -- any decent spectrum display can be a BIG help in chasing
and identifying RFI.
73, Jim K9YC
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