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Transverter Interface


Andy G4JNT
 

Well, I must really be losing it in old age here...

A slightly earlier version of this FT817 (and similar) transverter  interface without the DC switching  was  written up and published in RadCom Dec 2013, page 60.

Which I'd completely forgotten about until now!     So perhaps just as well I didn't get round to writing-up the whole thing all over again!

Found the text for that and incorporated it into a new version, to be found at 

Andy  G4JNT


On 29 June 2016 at 08:42, Andy Talbot <andy.g4jnt@...> wrote:
Is it worth writing this up, or are there already commercial designs that people just plug-n-play with?

A single board transverter interface that connects low power transceivers such as FT817 (or that olde favourite. the IC202) with low power mixers.  Single bi-directional mixers or separate Tx/Rx are catered for.    It extracts the PTT signal superimposed on the transceiver RF, generates +VTx and +VRx voltages at a couple of amps switching capability, and uses PIN diodes to switch RF through an attenuator on Tx and straight though on Rx.   A PIN diode on the Tx path allows varying the Tx drive level with a  DC  control signal.  Not a relay in sight

All components available via the catalogue suppliers or Chipbank if you're prepared to substitute and experiment a bit.


Mike Willis
 

The FT817 is a popular driver radio for portable work. Given that it has two antenna connectors, it seems to me that a good way to provide a transverter interface is to modify the radio, rather than have an external box to worry about and wire up incorrectly in the field.

Most transverters, particularly if used with a pre-amp have far too much receive gain and would benefit from 10-20dB in line attenuation on receive. So, the simple bodgers method shove an appropriate attenuator in line with one of the connectors and also a blocking capacitor and DC feed for standard volts on TX PTT. All done, no need for PCBs and PIN diodes. Relatively fool proof too.

Mike