I've just decided to buy myself a WS2300 by La Crosse. By all accounts
these are supposed to be quite good for the money.
Obviously it depends how much you want to spend.
Do a search on deja and you'll find quite a few articles in
alt.sci.weather (I think).

As for the RF-Tech, I might try drawing out the cct to see if I can
make some sense of it.

Bob