Pagina 36
KB2LJJ Radio Mods Database and Manuals
03/05/2008 08.24.31
http://www.kb2ljj.com/data/yaesu/ft-817.htm
Ready:
FT-817 10 Watts output
There are suggestions to set the FT817 to get the maximum possible output of 15 Watts from an FT817,
but I consider this similar to believing in Santa Claus – do you really believe that Yaesu would over
design the Filters, Relays and Power feeds to cope with THREE times as much power as they advertise
the unit for ?
The 15 watt mod also totally disables the DC current limiting. Expect to see charred coils, DC filters and
PC board next time you look inside your rig – a fan on the heat sink won’t stop this. For a rig that has no
over-temperature indication or protection of any sort, tripling the power level is designing for disaster.
This procedure here will increase power to 10 watts on HF bands only, but ensures that the DC Over-
current protection will reduce power into abnormal loads that the SWR detector cannot detect. SWR
bridges are a only a compromise at detecting reflected power – that’s why Yaesu went to the effort of
building in DC Over-current protection as well as high-SWR protection.
Here is the recommended procedure, you will need a Dummy Load and a Wattmeter or RF Voltmeter.
Make a note of your original calibration settings so you can go back to the standard setting later – the
easiest way to do this is to use FT817 Commander freeware. It is also easy to accidentally change a value
by bumping the Dial knob, and you need to be able to get back to the original setting.
If you have a Key connected, set the VFO to CW on 1.8, 7 and 21 MHz bands – if you don’t have a Key,
then set them to PKT and you will be able to get full carrier using Mic PTT but with no modulation going
out.
