Electronics > Projects, Designs, and Technical Stuff
Radio Direction Finding
PA3BNX:
Hello every body,
I got a tip from to get easy a nice beautifull sinus out of the
SuperSimpleSoundDoppler
I want a nice sinus because it looks better on the inputXY screen
It has less harmonics so the left right preamps are heving less
trouble with crosstalking of the soundcard.
Just hook the lowpassfilter with the transistor at the end on one of the
outputs of the 4001 output ports hi...
Why didn't I thought of that before.
I have to change the PCB layout just a little bit.
Another errro on some circuits is that a 4060 has no Q10 output..
Wow thats strange they where out of pins on the dil package hi..
oe6rke
My SoundDoppler can save only wave files and has no gps latitude an longitude info stored
in the filename.
But wave file audio-loggen was meant for stationairy logging purposus.
But MyMapping has logging facilities of the packet.txt.
In packet txt is al the needed info for finding out at witch time date and place the logged
wave file belongs.
PA3BNX:
Hello Every Body,
Here are the PCB Layouts of the pe0ssb
softswitcher antenna boards
Upper and lower side of the HF part
PA3BNX:
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.
PA3BNX:
Hallo Every Body,
Today i did some playing with the SuperSimpleSoundDoppler
generator and I wanted to improve the sinus output of it.
I come up with minor changes.
I did replace the elco for a 1k5 resistor
after the bc547 buffer emittor follower.
and I did put a smaller elco 2u2 in series with the potmeter.
Amazing on my scoop to see that the envelope of the output sinus is much better
looking now.
The lowpass filter now has a series extra resistor (1k5)
and is feed ed without the Xc of the elco.
The PCB layout is very simple to change.
So suk6
See the circuit diagram in the fl yer for details
PA3BNX:
Hello Every Body,
Some notes about the 4 whips
and running it at 2 meters and 70cm.
The optimal diagonal distance between the antennas for
2 meter
is about
300/145 * 0.35 = 0.72 metres
For 70 cm
is about
300/.70 * 0.35 = 0.24 metres
(Factor 0.35 comes from sqr( 0.25^2 + 0.25^2)
The maximum distance between 2 adjacent antenna may be 0.25 wave length
If the frequency gets above the calculated then the distance between antenna diagonal
then you get ambiguity.
So lower frequency is okay only you will have lesser doppler-tone-amplitude.
Ideal would be 4 J-antenna's they don't need a ground plate and the coax cables are not
in between the antenna fields like with the GroundPlanes or center fed dipoles.
On 70cm the capacity in the off situation becomes more important.
Also the cables must be of better shielded quality.
If you use the SuperSimpleSoundDoppler antenna switcher the 4 coax cables must be for
2 metres:
300/145 * 0.25 * 0.66 = 0.34 meters
0.70 metres:
300/435 * 0.25 * 0.66 = 0.11 meters
Very important with 1/4 antennas is the ground connection from the coax
to the base plate.
The biggest current is in the feed point of the 1/4 antenna so base plate must be connected okay
there.
Do not make the coax shield become an antenna and make sure the whips are have omni directional patterns
so there must be more place on the groundplate (Do not put them on the edges of a base plate)
I use for 2 meter a circle base plate of about 60 cm diameter and about 30 to 40 cm
diagonal space between antenna's
I hope this is some help for building the antenna system.
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