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Radio Direction Finding

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PA3BNX:
Hello Every Body,

I found very nice site for a doppler direction finder

Dopplerjev iskalnik smeri
http://matrix.uni-mb.si/projekti/objava/vsebina/91/




All circuit and sources are in English on their sites.

I think it only needs softswitching so just ad 4 transistors to it.
See my supersimplesounddoppler de luxe circuits hi.

The Doppler gets much beter with soft switching
for weak signals and strong adjacent channel signals.


Further I saw that DopplerSys has software for an Android Smart Phone

http://www.dopsys.com/software/MPT%20User%20Interface.html

So Happy Hunting and Building





PA3BNX:
Hello Every Body,

Now I retry to get the crossloops and sense antenna running on
my sounddoppler software with an Am radio on abt 3.6MHz

The two loops are tuned by separate C's

The meaning is that a loop + sense antenna gives a 1 + cos(phi) pattern

Bij switching the loops + sense I get four directions and these can be detected
bij SoundDoppler running with SinCos(Correlation detector).

So any advice welcome

I am building now the new electronics for it see the diagram below.

The core is something like t50-2 with trifilair windings 3 x 8 to 10 turns I think.

HUTCOMINT:
 PA3BNX:

How much of these circuits do I need If I'am using a RTL-SDR?
I was thinking I might need only the antenna switcher, but then I see it has a 5-pin din that goes to God only knows where.

Thanks.

PA3BNX:
Hello All,


You  do need a reciever with FM for the doppler

It's not possible Yet to do it with just an SDR DVBT T820T
Because you have latency in the I en Q stream from the stick

So you need a separate FM RX
And a generator like the 4017circuit and a antenna array switcher and 4 antenna's

The 5pin Din connector is for the control conection from 4017 generator to the switcher unit
Every wire in  the 5 pin din switches just an antenna on and off through the diodes on the antenna switcher
So 4 wires and earth wire

It's all in the program zip file SoundDopplerAll142a.zip


Today I did made pictures of the CrossLoop with sens antenna for 3.6 MHz
with the soundcard interface
This must run with an Am 3.6MHz reciever
It works quite wel even indoor hi.
See picture below.

DH8DL:

--- Quote from: PA3BNX on February 15, 2012, 07:00:01 pm ---Hello Every Body,


Here I send the lower part where the
PLL RF and softwitch pulses are made.

These boards are connected by wires close together.

--- End quote ---

There are errors in this PE0SSB layout. Actually it's 1 error which is repeated for all 4 Antenna Switch logic Controller circuits. I found out when i built this DDF96 3 years ago.
The Errors on this board are.:

R43 Needs to be connected to R10, not to R11
R44 Needs to be connected to R22, not to R23
R45 Needs to be connected to R16, not to R17
R46 Needs to be connected to R4, not to R5

Please check the circuit (from the PE0SSB Website) with the layout of this board and you will see.

Here is a Picture of the corrected Version.:

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