[Laser] testing receivers

[David Riley]

Am going over full junk box of tx diodes and need to classify same.
What do you think is the highest modulation freqs of the following =
transmit devices:
Are most diodas of any kink usually good up to 10 mhz or so?

3mw printer laser
30mw IR laser diode
Bright LEDs
IR led tx as used in tv remote tx

If I could get an idea of how high in freq. each will go it will be =
easier to check receive pins.

I use freq. divider from 10mhz down to .5 seconds for on/off by taking =
5V TTL sig out through gain control with milliameter for lasers and =
microameter for led diodes. Makes good relative test but doesn't give =
absolute values.. Then increase in Freq...
Can detect IR diode from R/S with nothing showing on 0-3 microammeter..
Crude but good test.. the .5 second makes good s/n test...


Re: 8x11 magnifier..  works good. I mount one into a shipping case after =
making 8" hole. The case also holds the goods needed to go on the road. =
Am using universal sink drain hardware from hardware store and cut PC =
boards for RX preamps or receivers to slide inside metal pieces.. 1.5" =
hardware..
Just gaze at the selection of this stuff at the store and see what comes =
to mind.

A 4" lense from a magnifying lamp or from Edmunds does great when =
mounted in 4" PVC and you can use the end caps and other PVC hardware. =
Lightweight shroud about 2-3' makes for better s/n day or night.

Micrometer x-y tables with tx diode mounted makes for good aiming, will =
remote with dc motors and elastic drive belts.

Presently using A1-A2-A3, subcarrier FM, and VE2IQ BPSK @ 800 hz.
Also 10mb ethernet rx/tx...

Looking to make a light version of the old military APN-1 radio =
altimeter but use laser and APD...  Should be good hand held radar for =
boating..

Friend is converting old 3cm marine radar to laser diode tx and pins =
mounted in antenna pedestal, RT unit converted to LIDAR like modulation. =
 Having old, used, surplus bases and antenna takes the work out... Just =
drop in your stuff...
What you got for good ideas?   Best way to broadband pin? Lo 'R' in =
parallel??

So far 40/s9 comms on A3 mode @ 9 miles.. =20
Cloud bounce,  ether bounce only simplex so far..

73s de Dave - AA1A - @ www.radiocom.net/Fessenden






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