Mr. Mc Bride,
Thank you for this post. It led me to a Google search, which provide a great starting point to go along with Item No. 3 in your post. It is:
http://www.dxzone.com/catalog/Software/Antenna_analysis/
Thank you again,
Tim - N3TL -------------- Original message from "Art McBride" kc6uqh@cox.net: --------------
To All,
- Amateur Radio is learning by doing.
- A large amount of data on Yagi type antennas exists, easily found, and is
well proven. 3. Several design programs for antennas exist reducing construction time and waist of materials. 4. Equipment to measure comparative antenna performance at VHF/UHF frequencies is not hard to find.
Why do we line the pockets of some poorly designed antenna manufacturing companies instead of learning how and making the best performing antennas for our own use? If we do not learn these skills, no one will be left to teach and the skills will be lost.
There are many older Amateurs willing to teach those that want to learn, and hopefully many of those wanting to learn are at least one half of the age of those who can teach!
Art, KC6UQH
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Jim Danehy Sent: Saturday, December 27, 2008 6:33 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Fw: ELK or ARROW
. there is the old adage that you get what you pay for . . . why buy a poorly designed antenna that does not work very well
?
If you have a 5 element yagi that only produces 4 dbi you are not getting
what you paid for . . . most 2 element yagis would out perform that statistic . . . a 5 element yagi should be at least 9 db + or 10 db dbd (dipole ) not isotropic . . . . there is something that is called MERCHANTABILITY . . .i.e., an IMPLIED WARRANTY that you are getting at least the minimum for your money . . . 4 dbi for an Arrow is way off base . . . so it is not just ; you can not afford a Cadillac but you are not even getting a Ford or Chevy . . i.e.,
the gain of a 5 element yagi on 435 mhz . . . that is the issue, not cost
alone . . . . . . same comments apply to the ELK but I have attempted to make the point that there is a minimum performance for a certain number of
elements that is pretty OBJECTIVE and when it is not met . . . . well that is my point . . . these two antennas have shown to some testers that they do not measure up to the minimum EXPECTATIONS . . .unfortunately that
is acceptable to some . . . . then it becomes acceptable to many . . . and objectivity is abandoned . . .
Jim W9VNE
----- Original Message ----- From: "Trey Brown" To: "Jim Danehy" Sent: Saturday, December 27, 2008 6:39 PM Subject: Re: [amsat-bb] ELK or ARROW
Thanks for the comments. Realize, though, that not everyone wants or can afford to have the Cadillac.
On Sat, Dec 27, 2008 at 4:06 PM, Jim Danehy wrote:
the Arrow antenna has been critiqued by Kent Britain, WA5VJB
http://wa5vjb.com/references/Cheap%20Antennas-LEOs.pdf
he says that some have measured the Arrow for gain on 435 mhz @ 4 dbi (isotropic) . . . . and that further analysis showed that for the element lengths used on 435 mhz that it peaks at 457 mhz and not 435 mhz
. . . Kent is a well respected VHF/UHF antenna person who has plenty of credibility . . .
Kent opines that the Arrow, as built does not have its elements insulated from the boom. It uses dimensions for insulated elements . . .
so much for the Arrow . . . .
Now for the ELK : a local friend of mine owns an Arrow and he uses it successfully. He bought an ELK and attempted to compare the Arrow and the ELK . . . . he could not make an across town QSO on 435 mhz from his
second story window with the ELK , so he sent the ELK back for a refund .
I have worked and exchanged QSLs with several hundred satellite users . . .the majority of the folks that have worked and QSLed me (close to 250
- ) have been using either the Arrow or ELK based upon the information
on their cards. So they are popular. Are they optimum ? A lot of anecdotal information would seem to say NO . . .
Thirty-five years ago I worked Oscar 6 with a homebrew 2 mtr yagi that probably was worse than either the Arrow or Elk but I worked YV and KL7 from Indiana on CW with about 15 watts to the 3 elements which my XYL waved around at my directions . . . not any more . . .what do I use these days : a pair of circular polarity yagis on 10 foot booms manufactured by M Square . . . .
Folks ask what should they buy ? Maybe a Ford or maybe a Chevy . . . neither is a Cadillac . . . .
Jim W9VNE _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
-- Trey -- N5THX
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety.
- Benjamin Franklin
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb