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.
at

3 comments:

  1. AnonymousThu Jan 27, 10:27:00 am GMT

    Hello Roger

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

    KR Tony G4LLW

    ReplyDelete
  2. Roger G3XBMThu Jan 27, 11:13:00 am GMT

    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!).

    ReplyDelete
  3. g4freMon May 29, 03:43:00 pm GMT+1

    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

    Dave
    G4FRE

    ReplyDelete