Electronics > Projects, Designs, and Technical Stuff
Radio Direction Finding
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PA3BNX:
Hello EveryBody,


Today I did again some work on the new plate antenna.

It works I think but the switcher needs + and - volt control signals
so it needs something like a max232 that has a feed of only +5 volt and generates rs232 + and - voltage
signals.

I think I am going to build a small PCB with the max232 that can be connected between
a standard 4017 SuperSimpleSoundDoppler generator.

The circuit of the 4017 in the file above Rommeltje2.png does not work because you need
+ and - control signals.

Today 27-05-2013
Replaced Rommetje2.png in Rommeltje3.png with max232
Today 04-06-2013
Replaced Rommeltje3 with Rommeltje4.png

My antenna plate is now 22 by 22 cm and hight above groundplate about 5 cm

I get an SWR of about 1.6 at 2 meters it looks the antenne is directional and switchable

I dit create the 2 control signals 15 and 20

with my + and - 5 volt supply and two tumblers to test al configuration with the switcher.

Take look at these patents:

US3202995.pdf
US4510498.pdf
US4635065.pdf

Antenna could be called a traveling wave antenna
or even looks like a beverage antenna.

PA3BNX:
Hello Every Body,

Here a is picture of the Traveling Plate Direction find antenna
prototype.


SeanB:
There are a lot of those adorning police cars here, as a part of the Tracker system.

Of course, at the moment the police are on strike over pay, watched the demo today at lunch time as I drove past.
PA3BNX:
Hello EveryBody,

I just did do some drawing of the driver for the plate antenna.

Just a 4060 and a lm358

No voltage regulation needed I think


The opamps should switch between + and -

So I should build this one on breadboard to see if it's working !

Whoops replaced the drawing because the - inputs off the
lm358 has to be on 1/2 positive tension to let them switch between
+ and - voltage

Now it should work.....

Here a nice link about the Wullenweber HF direction finding

http://www.navy-radio.com/frd10.htm



PA3BNX:
Hello EveryBody,


Today I finally got the rs232 max232 running on Matrix board.

I had ta place two pulldown resistors in of 4k7 at input of the rs232 driver after the 1n4148 diodes

Finally I could test the new antenna and it worked strange.

I found that the fast control signal must be connected to the center antenna plate control
(connect no 15)

I did replace the drawing in Rommeltje4.png some messages above.

So first the sequence was antenna 1 3 2 4
and now it is 1 2 3 4



Tomorrow I do some more test with the antenna.
On my FT817 in AM mode on 2 meters and with a small fox transmitter.
It looks it works all all right even indoors.


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