Electronics > Projects, Designs, and Technical Stuff
Radio Direction Finding
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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