(Click on image to enlarge)
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This radio can be used as a normal cave-radio (including radiolocation), for
this you need two of these sets.
It is also designed to use with the earlier surface radio as well as the new
surface radio (will be published end of November).
The earlier surface radio is only capable of making a connection to a VHF-radio.
This version is also capable to send commands for calling the VHF-radio at the
basecamp (like an alarmsignal), record and playback messages.
All functions are generated and controlled by a PIC16F84 microcontroller.
For these the PIC generates 3 tones. SOT (Start Of Transmission) 1200Hz, COMMand
(1500Hz and EOT (End Of Transmission) 1950Hz.
The use:
Normal use:
When the PTT-button is pressed; transmission begins and an SOT is generated
which will be repeated every 10 seconds.
This repeated SOT-function will be detected by the surface radio (and sustain
the VHF-link for another 21 sec).
When the PTT-button is released; EOT is generated and transmission will stop.
Call:
Calling the basecamp is possible by setting the Command-switch once (Call-led
= on).
After pressing (and release) the PTT-button the following tones are generated:
SOT - COMM (1x) - EOT.
Play:
Playback any recorded message (will be stored at the surface-radio) is possible
by setting the Command-switch twice (Play-led = on)
After pressing (and release) the PTT-button the following tones are generated:
SOT - COMM (2x) - EOT.
RECord:
Recording any message (max 40 seconds) is possible by setting the Command-switch
three times (REC-led will flash for 40 seconds).
After pressing (and please hold this time) the PTT-button the following tones
are generated: SOT - COMM (3x).
After releasing PTT-button an EOT will be generated and transmission will stop.
Beacon:
This function can be used for radiolocation.
Set the switch to 'beacon on'. An SOT and EOT will be generated until the switch
is off.
At every SOT/EOT-cycle there will be a 2 seconds pause where the radio is switched
to receiving mode (so communication is still possible).
Adjusting the receiver:
It's very simple; Set your tonegenerator at about 89KHz with 20cm wire at the
output.
Adjust the (TOKO)coils L5 & L6 until best result is heard.
VR3 is to set the AGC. VR3 has little influence but the AGC works fine.
Adjusting the transmitter:
Set your tonegenerator at 1500Hz & 20mV and connect its output to the mic-input.
Press the PTT-button and adjust (TOKO)coil L8 to maximal amplitude at your scope.
Adjust VR1 until maximal amplitude (at a nice sine wave).
Then connect the mic-input to Gnd and adjust RV2 until you get a flat line (as
flat as possible)
Repeat this procedure until best results are made.
note: L7 needs no adjustment.
Construction details:
(Click on images to enlarge)
Mounted PCB
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Inside radio
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Battery compartment
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Electrical design.
You can download two files:
Cave radio (sept 2001).PDF (use
Adobe Acrobat)
Radio design (sept 2001).DSN
(made with Proteus lite)
PCB-layout.
You can download five files:
PCB Cave radio (bottomcopper).PDF
(1:1 bottomcopper / PCB-film ready)
PCB Cave radio (topcopper).PDF
(1:1 topcopper / PCB-film ready)
PCB Cave radio montage bottom.PDF
(with all parts at the PCB-bottom)
PCB Cave radio montage top.PDF
(with all parts at the PCB-top)
RadioPCB (sept 2001).LYT (made with
Proteus lite)
Construction details.
Construction.cdr (CorelDraw-file of construction)
Construction.pdf
Front-layout 14-9-2001.PDF
Front-layout caveradio 14-9-2001.PUB
(MS Publisher file)
Partlist.
Partlist cave-radio.xls
Partlist cave-radio.PDF
Software.
tonecoder.psf (Basic-like program, readable with
a simple text-editor, like notepad)
tonecoder.asm (assembled sourcefile, also readable
with a simple text-editor)
tonecoder.hex (to be programmed in the PIC16F84)