On Mon, 10 Oct 2005 14:20:09 GMT, Cecil Moore wrote:

....
I don't know much about small loops. Modern transceivers,
like my IC-706, have such good protection circuitry that
it can be tuned into any load at full power. Is there
....

I know it is common practice to tune screwdrivers for max power out
from IC706s (tuning for "maximum smoke"), but is that good for the
tuner?

Perhaps that is why Icom incorporated low power tuning of its system
tuners. The AH4 actually presents a very limited range of Z to the
radio, it effectively introduces a small attenuator at the tuner input
when tuning. So the radio is limited to around 10W, the Z excursions
are limited, and the tuner relays operate at quite low power. I wonder
what they know that we don't?

Perhaps it is why Kenwood drops carrier before each relay operation in
autotuning the TS2000 internal tuner. (Some of their earlier models
have a reputation for tuner relay failure.)

It may be that tuning screwdrivers under full power isn't detrimental
(I just don't know), but it is probably not safe to generalise.

Owen
--