"JArthur" wrote in message
oups.com...
If a longer antenna is better then why do they sometimes have to be cut
shorter when tuning?


Actually, as long as you have an antenna tuner, the antenna need not be
resonant.

Years ago, the military used rhombic antennas for point to point HF long
haul communications. The monsters on Guam were 600 feet on a leg (they were
in a diamond shape) and 200 feet in the air. They were used on a large
range of frequencies (one fixed size antenna) and simply had the reactance
tuned out to present a good load for the transmitter. These things had
gains that would put most Yagis to shame.

That said, most of us use tuned antennas and then feed the things with 50
ohm coax and we don't need antenna tuners. 1.5 to 1 or below is excellent.
2 to 1 is about the highest you want to see without adjusting the antenna to
bring it closer to resonance (if, indeed, that is the problem - a vertical
over salt water will show around 36 ohms impedance when it is exactly
resonant, rather than the nominal 50 ohms). Surrounding metal, imperfect
grounds, and other problems can cause the antenna impedance to be
above/below 50 ohms and exhibit some SWR. As long as your 1.5 or below,
you're fine!


73 from Rochester, NY
Jim