Short boom (<20 ft) Log Periodic Antennas generally have moderate
gain (4 to 6 dBi or so) and F/B on each of the amateur bands.
This same level of gain and F/B can easily be obtained with 2L Yagi's
which have reflectors lined up by frequency. The trick is to make an
efficient driven element for each band.
The Force 12 C3 does this effectively on 10 / 15 / 20 M using parasleve
driven elements. I would love to see them come out with a 5 band version
covering 10 / 12 / 15 / 17 / 20 M.
The C4 includes 40M.
Sometine during the last sunspot maximum,
I modeled a 2L 5 band Yagi using separate reflectors
and a single split dipole driven element tuned to 15M and fed with ladder
line. The gain figures peaked nicely at each band where the reflectors
were tuned. I built a 3 band version of this antenna covering 12 / 15 /
17
meters which I used primarily on 12 and 17M, side mounted at 50 ft on
one of my towers and aimed towards Europe. It "played" well but I have
no measured patterns or gain numbers to confirm performance.
de Tom N4KG
.............................
On Sat, 02 Jan 1999 13:20:20 -0500 Bob Thacker <k3gt@pgh.net> writes:
>
>Would like comments about the KLM 10-30 Log Perodic. Only have 22.2 SQ
>Ft of allowable wind load on the tower and already have a Hygain 402BA
>up. Or...what would you put up to have 40 thru 10 on 1 tower with the
>windload?????
>
>Thanks for the comments...HNY
>
>Bob, K3GT
___________________________________________________________________
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
|