Pagina 37
KB2LJJ Radio Mods Database and Manuals
03/05/2008 08.24.31
http://www.kb2ljj.com/data/yaesu/ft-817.htm
Turn the radio off. Press and hold the three A, B, C buttons and press the PWR button. To change to a
different Menu item turn the small SEL knob. To change the value of the item, turn the large Dial knob.
Be careful not to bump the Dial knob so you don’t accidentally change settings..
1.
Increase HF1-IC to 150.
2.
Increase HF1-HI for an output of 14 watts - you will need at least 12 volts input.
3.
Decrease HF1-IC until you get 12 watts output
4.
Now set HF1-HI for 10 watts output.
5.
Repeat for HF2 and HF3
You could also change HF1-L3 to 5 watts to save battery drain when 10 watts isn’t needed.
If you are using an RF Voltmeter the readings are 0.5W=5v 1W=7v 2.5W=11v 5W=16v 10W=22v
12W=24v 14=26v.
To avoid de-calibrating the Voltmeter, set your supply to 13.8 volts – otherwise if you just flick over the
DC volts position (Item 17 - VCC) you will recalibrate it.
To save these changed settings, hold the F button for two seconds when finished.
User comment
Subject:
blown finals and 10 W modification
Hi OM,
This topic is very hot in the world wide FT817 discussion groups.
I think we have to strike the balance of getting 10 watt output and risk of blown finals. Increasing
the output power is definitely not an original design parameter. Otherwise, Yaesu should promote
the rig as 10 watt output and sell for higher price.
Based on this rationale, I keep the variations to the original values in the hidden menu #18-53 as
few as possible. My rig is the Lot 58 production and my observations are:
1.The gain of the finals at VHF and UHF regions is well less than that in HF region so that there
is not much room for increased output. For example, the difference between 7 watt output and
the original 5 watt is merely 1.46 dB. Therefore, why border to make any variations to the
original values.
2.For HF and 50Mhz, an increased output to around 10 watt can be obtained by simply only
changed the values at #24,28,32 and #36 i.e. HF1-HI, HF2-HI, HF3-HI and 50M-HI. Therefore,
the changes to the original design parameter are kept to minimal. In other words, there is no
