40 m inverted vee question?????
 

My 40 m reson. iv used to be completely horizontal at 30 ft.

I had to bend one end (while leaving the other horizontal) at
about a 45 deg angle to about 10 ft above the ground.

The SWR seems to be higher. 1.5:1 at its lowest. I can't remember
what it was before but I know it wasn't this high.

Will this cause an efficiency problem or any other?????

Hi Capo:

The Z of an antenna changes with its height above ground. It is not a liner
function but follows a curve. There is a chart in all antenna handbooks
showing the change with height above ground. Anyway you lowered the average
height of your antenna so you changed the Z of the antenna. Lowering the
antenna will change the shape of the radiation pattern. It will not change
the efficiency of the antenna, if you put a 100 watts in it will radiate 100
watts.


--
John Passaneau
Penn State University, State College Pa.
W3JXP

"capo" wrote in message ...
My 40 m reson. iv used to be completely horizontal at 30 ft.

I had to bend one end (while leaving the other horizontal) at
about a 45 deg angle to about 10 ft above the ground.

The SWR seems to be higher. 1.5:1 at its lowest. I can't remember
what it was before but I know it wasn't this high.

Will this cause an efficiency problem or any other?????

capo wrote:

My 40 m reson. iv used to be completely horizontal at 30 ft.

I had to bend one end (while leaving the other horizontal) at
about a 45 deg angle to about 10 ft above the ground.

The SWR seems to be higher. 1.5:1 at its lowest. I can't remember
what it was before but I know it wasn't this high.

Will this cause an efficiency problem or any other?????

you have lowered the resonance of the system.. you will need to shorten the
antenna a bit to bring the swr down.. though 1:5:1 is not that bad.
73 dave kc1di

--
RED HAT LINUX 8.0

you have lowered the impedance of the antenna, not the resonance, and thus have
a mismatch at the junction of the antenna and the feedline, which causes the
swr. You can add a balun, change the impedance of the feedline, or transform it
at the transmitter either with an additional piece of coax, or with a tuner.