>I wonder if the UK is unique in specifying power limits _at the
antenna_? In other words, you can run whatever power you need in order
to overcome feedline loss.
I don't>believe it's a healthy regulation - it hardly encourages good
engineering of the station!
>Steve G3TXQ
Isn't that a little pernickety, worrying about whether to measure power at the
feedline or right at the antenna? The RF power input to the radiating element
is what determines the signal strength and therefore interference potential,
which is what maximum power rule is trying to limit.
Maybe it could be an issue if you use commercially manufactured equipment with
factory specifications, but becomes a moot point if you design and build your
own. My homebrew transmitter has a three-stage output network, starting with
the tuned circuit at the anode of the final, followed by a balanced L-network,
and ending up with a parallel or series tuned circuit which may or may not
include a tapped coil, depending on the antenna and band being used. When I
designed the system, entirely myself, I decided to locate the final stage of
the matching network remotely, at the base of the tower, linked back to the
previous stages of the network via a balanced, untuned open-wire line. The
actual output terminals of the transmitter are located on a wall of the
enclosure at the base of the tower, and either feed the base of the tower
directly against the earth connection when the tower itself is used as a
series-fed base-insulated vertical, or the balanced open wire tuned feeders tha
t run up the tower when I'm using the dipole mounted near the top.
No-one can contest where the "output terminals" of my transmitter are located,
since I'm the one who designed and built the entire system (transmitter,
transmission line and antenna) myself, therefore I can locate the output
terminals anywhere I well please, and there was no commercial manufacturer to
designate where the latter are physically located.
BTW, everything in the transmitter/feedline/antenna chain is coupled together
and fed with open wire; not a sprig of coax anywhere in my entire system.
Don k4kyv
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