25 Jan 2011

FT817 antenna pin: getting a DC voltage on the inner when on TX.

The FT817 does not have a DC voltage change between RX and TX on the antenna connector, unlike the old IC202. This voltage was very useful to switch PAs and transverters. I now know how to modify the FT817 to add this feature thanks to Chris GM4YLN who sent the link http://www.kolumbus.fi/oh5iy/HW/Yaesu.html showing one way to make the mod.. Note in this link the FT817 is wrongly called the FT718. An easier to implement link is shown at http://www.bergtag.de/download/ft817.pdf . Thanks again to Chris for this one too.


Anonymous said...

Hello Roger

Would an RF switching option for the transverter be another solution
for rigs still under waranty


Roger G3XBM said...

Yes it would Tony with a TX off delay to cope with SSB. I think I will make the mod as it looks very easy to reverse if ever the FT817 was sold (very very unlikely!).

g4fre said...

Thanks for the links. One point to note in the OH5IY method, as I have just found, is that the "TX5V" line will never measure 5V. The 5V is sourced through a 100 ohm resistor and the final PA module hangs a 3.9V zener on the line, so you will see ~3.9V. Still enough though to switch the Transverter