Browse By

Yaesu FT 817 Modifications – Tips and hints

There are many ham radio modifications for our Yaesu FT 817 ND available on internet.

BATTERY life
One of the problems with the Ft 817 is the  poor battery life, particularly using the normal NiMH pack with 1,400mAH capacity that YAESU provide. One solution is offered by VK3YY. He proposed to use a Lithium Polymer battery . Hobbyking have this lipo battery that is a good fit inside the FT-817.  The pack is a bit narrower than the original NiMh pack and about 50 grams lighter at 150 grams.  The capacity at 2500mAh is significantly more than the original pack.  The price is around 20 $ plus postage. (See photo – perfectly fit inside!)

FT817 PA Failure

It seems that I am not the only radio amateur to have the PA on my FT817R fail without warning or provocation. It seems that the older FT817R’s were prone to sudden PA failure and that this may be linked to a problem with self-oscillation of the power amplifier stage resulting in its destruction. The PA is driven hard on 2 metres and 70cm as the gain of the devices is lower. This might not help much either, in terms of PA life. Click down here for the video-link.

When the PA is replaced, there is apparently a Yeasu factory modification that is done to the final stage PA circuitry to improve reliability.

cropped-ft818-e1407095442414.jpg

RN3AUQ write us another modification about
” How to improve FT 817 receiver “

The source of receiver noise is 2nd IF amp which is placed after the 455kHz IF filters. So, you can replace R1339 10k by 1k resistor and this will reduce total 2nd IF gain. To restore transceivers sensitivity you should boost 2nd IF local 455kHz oscillator. It can be done after replacing R1195 220k by 100k resistor and R1196 2k2 by 1k resistor. After the mod check your receiver sensitivity with RF generator and fine tune it in service menu (press A, B, C and switch power ON) items HF1RX, HF2RX, HF3RX e.t.c

” How to get 10 watts output from Yaesu ft 817 nd “

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.

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.
Click below on the arrow to go to the best link we can suggest: All the mods, modifications for our QRP radio world are here…

 

 

mods.dk website!

Comments

comments

Leave a Reply

Your email address will not be published. Required fields are marked *