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Repurposed Toshiba laptop supply for Yaesu FT-817ND Radio

I'm traveling to Ireland and the UK next week, and plan to carry my Yaesu FT-817ND for a bit of radio work during the lulls in our trip.  The rig transmits at a maximum of 5 watts, requiring a maximum of 2 amperes to operate.  The rig accepts up to 16 volts DC.  The bundled power supply offers just a meager 0.5 amperes at 12 volts, just enough to run the receive and internal battery charger.  According to Trish's FT-817 QRP Page, the rig will switch to the internal battery on transmit if the external supply voltage is insufficient to carry the transmitter as would occur using a low-current source.  That's great, but the 8 hour charge time versus the 1 hour or so of useful operating time makes the prospect of this hybrid solution not so good, even if I can bridge the receive time with the external source.

Completed power supply repurposing

One of the great benefits of being a Resistor is access to a large collection of components to repurpose, and one such collection is our big box of wall-warts.  I rummaged through the bin hunting for a supply that put out a nominal 12 to 16 volts and at least 2 amperes of current.  I came across an old Toshiba laptop supply with a nominal 15 volts and 4 ampere capacity.  This supply also has a nice world-friendly input range.

Power supply repurposed for ham radio

I'm not absolutely sure that the supply won't create enough switching noise to interfere with transmissions or the noise floor on HF, but a quick simplex test on FM with the internal charger running did not reveal any hum on the transmit signal.  I'll work with it more, but I have little time before we depart.

73,
KD4ISF

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