DIY DF device

The following site is a similiar setup they give circuit diagrams and all
for the complete unit! They call for fm demod though although you can get
scanners that will cover the air band with fm also.


http://members.tripod.com/~clearRX/PRDFUNIT.HTM


John


Like Jim's system most of these DF units do not depend on modulation modes
they use doppler effect and electronically rotate the antenna.
Popular Electronics a few years back had a DIY article to built a df unit.
They used a 16 bit counter and used its output to diode switch pairs of
antenna to get the pattern then used 8 LED's to indicate cardinal
direction. They used an external receiver and audio output to drive it so
that you could use on whatever band you like changing only the
requirements for a resonant antenna.
It makes for a nice project though and not overly expensive!
John



Mattsson wrote:

So, this may be an utterly stupid idea, but...

I know I can get bearings from an airport, or more specifically the
tower, by using my com and talking to them when flying and within range.
Also, radio amateurs have these "fox hunts" where they hide a small tx
and then hunt it down.

Now, I have a scanner that covers the civil airbands on AM and I already
have built a few homemade base antennas for it, following some nice
designs made by others. This allows me to listen to nearby airfield
traffic pattern communication.

Now, it would be a lot of fun to be able to use my scanner with a
suitable antenna array, to get bearings to an airplane talking to for
instance tower. I know I know, you report positions most of the time, but
sometimes the small planes give pireps on local weather conditions and
the like, sometimes they just give position reports and so on, not being
that accurate on their position. At other times, spending time at
relative´s summer cottages, having the scanner with me, it would be great
to quickly get info on where to scan the sky for nearby airplanes on the
air, then get the binoculars. And as the chit chat on the airwaves
usually is very brief, there is no time to start pointing that yagi or
whatever to get some idea of where the plane is. You would need some kind
of automatic direction finding, something that would give a direction for
you in a second or two.

Is there anything like this for a DIY project? I googled a bit and found
a lot on automatic FM DF projects, but not for AM. It´s understandable
that most people are interested in searching FM transmissions, especially
those interested in finding noise sources and the like, but I´m just
interested in spotting and plotting those planes up there! =)

Any thoughts and suggestions appreciated, Ken

John
shared these priceless pearls of wisdom:

-
-
-
-The following site is a similiar setup they give circuit diagrams and all
-for the complete unit! They call for fm demod though although you can get
-scanners that will cover the air band with fm also.
-
-
-http://members.tripod.com/~clearRX/PRDFUNIT.HTM

Sorry, but the page or the file that you're looking for is not here.
• Please check to see that you've entered the correct URL.
• The owner of this site may have chosen to delete their membership.
• The site may have been removed due to a violation of Tripod's Terms of
Service.
• The site may have been moved to a different URL.

Please search again for this page, or others like it with the search box above.



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

OK I screwed up I don't know how that P got in there it should be
/RDFUNIT.HTM

http://members.tripod.com/~clearRX/RDFUNIT.HTM


John


Jim Weir wrote:

John
shared these priceless pearls of wisdom:

-
-
-
-The following site is a similiar setup they give circuit diagrams and
all -for the complete unit! They call for fm demod though although you
can get -scanners that will cover the air band with fm also.
-
-
-http://members.tripod.com/~clearRX/PRDFUNIT.HTM

Sorry, but the page or the file that you're looking for is not here.
• Please check to see that you've entered the correct URL.
• The owner of this site may have chosen to delete their membership.
• The site may have been removed due to a violation of Tripod's Terms of
Service.
• The site may have been moved to a different URL.

Please search again for this page, or others like it with the search box
above.



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

http://members.tripod.com/~clearRX/RDFUNIT.HTM

Jim Weir wrote:

John
shared these priceless pearls of wisdom:

-
-
-
-The following site is a similiar setup they give circuit diagrams and all
-for the complete unit! They call for fm demod though although you can get
-scanners that will cover the air band with fm also.
-
-
-http://members.tripod.com/~clearRX/PRDFUNIT.HTM

Sorry, but the page or the file that you're looking for is not here.
• Please check to see that you've entered the correct URL.
• The owner of this site may have chosen to delete their membership.
• The site may have been removed due to a violation of Tripod's Terms of
Service.
• The site may have been moved to a different URL.

Please search again for this page, or others like it with the search box above.



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

--
John Kimmel


I think it will be quiet around here now. So long.