Thanks, Glenn (W9IQ). Nice call, by the way.
At my home base I have just a simple 20M dipole, the bottom being just 6 feet off the ground,
running ~80 watts and and I get one contact about every 15 minutes, so receive/transmit ratio
is about 10:1, considering I'm responding to calls, but often not heard.
In a field setting, again with a lame, rickety antenna, I expect the ratio would be about
the same, maybe closer to 5:1 for a pile-up day like Field Day.
At most, I would be in operating mode for up to 4 hours in the field.
It IS easier to compute power then, with probably 150 watts on transmit and receive.
I estimate that would compute to about 800 watts over 4 hours, resulting in a drain
of about 70 amp-hours.
A 100-amp-hour battery might be sufficient, considering I would have at least some
charging ability from the solar cell. My estimate anyway.