During daytime conditions, my 40 ft TH7 is often better
than my higher monobanders, especially with higher
sunspots.
To cover ALL the angles supported by the ionosphere,
you need HIGH AND LOW antennas. 40 ft will cover
ALL of the angles supported above 10 degrees,
assuming a FLAT foreground. For this reason,
I recommend that everyone have a good tribander
at 40 ft in addition to higher antennas for nighttime
and band openings / closings or other marginal MUF
conditions.
BTW, the higher angles drop off faster (3 to 1) than
the lower angles increase as tower height is added.
To get the really low angles, 100 to 120 ft is desirable.
It has been my experience that 10 and 15 meter
antennas at 80 to 100 ft are notoriously POOR performers
during the day when LOWER really is BETTER,
again, assuming flat ground.
de Tom N4KG
___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
or call Juno at (800) 654-JUNO [654-5866]
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|