[Laser] led transceiver

[stuart.wisher at talktalk.net]

Thanks for comments from Sam G4DDK who suggests putting something in the RadCom GHz bands column, good idea; and Clint KA7OEI to whom I owe a debt of gratitude for his excellent front end design on which mine is totally based. Without the feedback capacitor it keeps going up to 100kHz so there is much space to play with subcarriers.


The transverter is based on a MC1496 balanced mixer, an op-amp to boost the output on transmit to really drive the Golden Dragon LED hard using  a MOSFET with a DC bias on it so the LED runs at 100mA and peaks up to around 1A on SSB. I use a 8.2 ohm resistor in series with the LED on FM and just 1 ohm on SSB at your own risk! (I have blown a 1A fuse and the LED is still with us). A logic IC and a 2N2222 looks after the ptt line.


Stuart G8CYW