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Yaesu FT817R Modifications

The Yaesu FT817R amateur radio transceiver is one of the most popular all-mode all-band portables ever made. It combines good receive performance with a 5 watt transmitter on all bands. There are many ham radio modifications for the FT817R available on the web and we provide details on extending the transmitter coverage below (a popular modification).

Transmit Extend / Expand Mods

Yaesu FT817The ZIP file below contains details of how to modify a European purchased Yaesu FT817R amateur radio transceiver to extend  or expand the transmitter operation to operate on the USA amateur radio frequency allocations of 146 - 148MHz and 440 - 450MHz, whilst retaining compatibility with UK 2m and 70cm band allocations.

The main appeal of the FT817R is its portability and with this modification you may be able to take your radio on holiday or on a business trip to the United States or Canada and make use of their different amateur 2m and 70cm amateur band allocations, subject to such operation being legally allowed under the reciprocal terms of your amateur radio license (see below).


In theory, these modifications allow a UK purchased Yaesu FT817R to be used in the USA, but only if allowed under the terms of your particular amateur radio license.

All ham radio licenses are different, depending on which country you live, so you'll need to check the legality of operating on 146 - 148MHz and 440 - 450MHz with the relevant regulatory body issuing your license. I wish to point out that I do not condone or encourage illegal operation of your station which may result in your being fined and/or your license being revoked.

These ham radio transceiver modifications are posted in good faith and you apply them entirely at your own risk. The FT817R contains small surface mounted components which can easily be damaged by inappropriate force of by the use of a large soldering iron.

Yaesu Ham Radio modifications - FT817FT817 transmit extend modifications (ZIP file download) - click here

FT817 Battery Life

One of the problems with the FT817R is poor battery life, particularly using the factory fitted 700mAh Nckel Cadmium battery pack. The solutions to this are to run the radio from a dry-fit rechargeable battery or to do, as I have done, and buy some 2300mAh Nickel Metal Hydride batteries. These extend battery life considerably and give about three hours more use than the factory fitted original battery. I found the 2300mAh batteries do self discharge quite rapidly though, so 1800mAh NimH cells may be a better compromise.

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.

When the PA is replaced, there is apparently a Yeasu factory modification that is done to the final stage PA circuitry to improve reliability. It seems to have worked on my radio as it has survived for a year without further problems after the PA devices were replaced under warranty.

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