[FoxHunt] Test

Tue Apr 28 13:38:12 EDT 2020

OK, well I'm not going to get involved in a discussion on this... it's a
waste of time.

The WinDopp display program does visual integration of DF bearings across a
( user defined ) time interval, to reveal "trends", just as you wanted.

If your question was serious, you can read more about it on the web page I
cited. 

The program is free, and accepts Agrelo format ( RS232 ) DF messages. 

Bob S.

-----Original Message-----
From: foxhunt-bounces at mailman.qth.net
[mailto:foxhunt-bounces at mailman.qth.net] On Behalf Of Bernie Hunt
Sent: Tuesday, April 28, 2020 8:06 AM
To: Radio Direction Finding
Subject: Re: [FoxHunt] Test

"Signal integration should only work if the errors are, themselves, "truly
random"."

I disagree. There are both short term and long term reflections that impact
the signal quality. (Note: I assuming mobile operation.) Short term are the
buildings and such that are passing. These can be considered random unless
you are driving the same route over and over again. Long term reflections
would be near the transmitter causing multiple signal paths to your
location. Signal integration should produce multiple possible target
locations that could be resolved over time. 

"Reflections are not really "random", they are just "uncontrolled", and too
complex to predict."
To my previous point, local reflections are random. I wonder if we have
different definitions of random. To me random is uncontrolled and
unpredictable. Are you possible considering a "normal" distribution vs truly
random?

I never saw a Pico Dopp in action so I can't comment directly. I can say
that computing power is much stronger these days and can do more. For
example your comment about flutter when stationary.  The readings when
stationary could easily be discounted in the calculations.

One thing that is interesting about the SDR is that it doesn't have the
traditional Doppler chop that keeps fixed units out of repeater sites. I
wonder if this would lead to a more friendly unit to tower mount.

Bernie
K2YO

-----Original Message-----
From: foxhunt-bounces at mailman.qth.net
[mailto:foxhunt-bounces at mailman.qth.net] On Behalf Of R. Simmons
Sent: Tuesday, April 28, 2020 10:40 AM
To: 'Radio Direction Finding'
Subject: Re: [FoxHunt] Test

Integrating ( apparently ) random Doppler readings was done years ago :

	http://www.silcom.com/~pelican2/PicoDopp/PICODOPP.htm#WDP

	http://www.silcom.com/~pelican2/PicoDopp/WINDOPP_MORE.html

===================

Signal integration should only work if the errors are, themselves, "truly
random".

If the errors are caused by a low signal level ( i.e. "white noise" ) then
it should work.

===================

Reflections are not really "random", they are just "uncontrolled", and too
complex to predict.

If you don't believe it, stop your car and notice that the signal "flutter"
stops...

Bob S.

-----Original Message-----
From: foxhunt-bounces at mailman.qth.net
[mailto:foxhunt-bounces at mailman.qth.net] On Behalf Of Bernie Hunt
Sent: Tuesday, April 28, 2020 4:51 AM
To: Radio Direction Finding
Subject: Re: [FoxHunt] Test

There is one thing that makes it hopeful, by capturing the readings and
storing them a trend may be found. I've always wondered if in those time
when a Doppler seems random in its readings if there was a pattern hidden
underneath the multipath. It will be interesting if the SDR DF can do that.
It doesn't solve and age old problem of if you can't hear it you can't hunt
it.

Bernie
K2YO

-----Original Message-----
From: foxhunt-bounces at mailman.qth.net
[mailto:foxhunt-bounces at mailman.qth.net] On Behalf Of Tony
Sent: Tuesday, April 28, 2020 7:32 AM
To: foxhunt at mailman.qth.net
Subject: Re: [FoxHunt] Test

HI,

We are having foxhunts every weekend. Let us know how the SDR DF works, I
suspect its like the old Doppler units.

Tony

AA9CC

On 4/27/20 2:58 PM, Mike (KA5CVH) Urich wrote:
> On Mon, Apr 27, 2020 at 2:34 PM Bryant <skysho at comcast.net> wrote:
>
>> Anybody have some good suggestions to get folks motivated?  Last year 
>> I
spent the bucks on the Kerberos SDR and have yet to take it out on a hunt.
Anybody else on this list using the device?
> I have the sniffer ... http://www.foxhunt.com.au/ and a 3L tape 
> measure yagi for VHF.
>
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