Depending on how much the top wire slopes down and if the end then
drops 10 feet straight down, the impedance could be around 50
ohms. With a 75 ohm cable, the 75 ohm SWR would be 1.5 and the
impedance at 1/4 wl down the line would be about 112 ohms. If Dennis
measures at this point with a 50 ohm bridge or antenna analyzer, the
indicated "SWR" would be 2.24. I'd like to know what he is using to
measure the "SWR", too.
73, Terry N6RY
At 04:14 PM 2008-08-29, K4SAV wrote:
>Thanks for the new data. EZNEC says that should be a good match for 75
>ohm line. The insulated wire makes a significant difference. I can't
>imagine that you would actually have an SWR of 2.8. What are you using
>to measure the SWR? If it is an antenna analyzer you may be suffering
>from the same problem many of us have, overload from AM broadcast
>stations. Try measuring it with a rig using a little power.
>DENNIS BRICKEY N4DD wrote:
> >I must have left out some pertinent information about my inverted L
> >14 awg insullated wire all the way around.
> >Vertical/L section of the antenna is up and over the top of an oak tree.
> >Radials mount to an 18" dia 1/8" aluminum plate.
> >175' total length radiating section 100' vertical
> >Horizontal section (75') slopes slightly downward for the majority
> of it's length. Maybe 10' straight down at the end.
> >No towers in play.
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