Paul Remde wrote:
Hi,

It is my belief that all the work required to make an "upconverter" will
lead to only minimal increases in your radios transmit power (10 to 20%?).
It doesn't seem worth it to me. I vote 12V.

Paul Remde


10-20%??? A discharged 12 volt battery is going to be around 10.5 volts,
with maybe half a volt lost in the wiring and fuses. The upconverter can
comfortably be set to 15 volts. The RF voltage follows the supply, so
it'll be 50% higher. Since the power is the square of the voltage, you're
looking at more than double the transmit power.

But the power isn't the big issue, it's the distortion you get at lower
voltage. Many radios sound really bad on transmit at 11 volts, and shut
down entirely at about 10 volts. Since they're 14 volt radios, that shouldn't
be surprising, should it? I just wish glider pilots had to listen to their
own transmissions, there's some really bad sounding radios on the air.

Upconverters aren't a bad idea, except for the potential for interference in
the cockpit. It's kind of a silly misuse of technology to be using something
like this, when it's so easy to get the proper voltage from a battery. I've
got nothing against them, I've designed them into commercial products where
appropriate, but this just isn't the best place for them.

-Dave