[FoxHunt] Test

[Bernie Hunt]

"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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