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Re: mode L antenna



Bob,

Check out this site to calculate your power loss:
http://www.timesmicrowave.com/cgi-bin/calculate.pl
For 20-foot of Aircom I substituted LMR-400, Loss = 0.9 dB Po = 80%Pin
For 80-foot of 7/8 hardline I substituted LMR-900DB, Loss = 1.7 dB, Po =
68%Pin
so for your total cable run the Loss = 2.6 dB and you will get Po = 54%Pin,
For Pin= 10w, Po = 5.4w
This ignores any connector losses so figure about 5w. Your EIRP = 500w,
since the 45-elem Loop-Yagi gain is spec'd at 20 dBi.

Yes for AO-40 you might be somewhat marginal.  I made some contacts at that
level but my signal was only about 1 s-unit out of the noise on AO-40.  On
AO-51 I would think it is fine!

73's Ed - AL7EB

At 09:31 AM 10/24/2004 -0400, Bob DeVarney WE1U wrote:
>I am having terrific results with a Downeast Microwave 45 element loop yagi..
>10 watts out of my TS-2000X into 80 feet of 7/8 hardline and 20 feet of
>Aircomm ( rotor loop ) seems to work very well on AO-51.. not sure what my
ERP
>is, and I doubt it would have been enough for AO-40.
>One hint passed on from N1JEZ, if you mount it upside-down ( to keep the
birds
>from cruching the loops when they roost on them ) seal the semirigid coax
feed
>from the N connector with some type of sealant. I used some automotive goop I
>had kicking around. Otherwise, it's a good place for water to settle into,
and
>that's bad! Good luck, and see you on AO-51 mode L/S some day!
>73 de WE1U
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