I to, am considering one of the directive systems loop yagis, their antennas are top notch in my opinion, and quite popular. There is a 9' long 1268 looper 45 element '2445LY' that claims 20 db of gain. Here is the link -
http://www.directivesystems.com/PDF/2445LY.PDF
At $120 + shipping and that's the pre built model.. save 20 and build it yourself.
I have been using their products for many many years.. and I've always been very pleased with performance.
You can see my directivesystems 2/435 yagis's on my webpage @
-Steve Raas N2JDQ FN20vg
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Edward Cole Sent: Monday, May 07, 2007 3:59 AM To: Greg D.; [email protected]; [email protected] Subject: [amsat-bb] Re: loop yagis
For what is worth, my two 45-element loop-yagis give gain of 23 dBi. They are 12-foot long and spaced about 16-inches apart. They are sold by Directive Systems.
A loop fed element in front of a 32-inch BBQ dish will not have anywhere near this gain and have many large side lobes. A dish needs to be >10 wavelength to exhibit nice clean beam pattern (23cm *10 = 230 cm or about 7.5 feet). I know many satellite folks are using a 4-foot dish so on transmit only this may be sufficient, though the beam will not be nice and waste much radiation in other than the desired direction.
I used one of the loop-yagis (20-dBi) on AO-40 with 9.5w with a marginal uplink signal. Either 15w or more antenna gain was indicated to produce an SSB signal comparable to mode US. of course P3E and Eagle requirements may not be the same as AO-40. This is the best we can do without precise knowledge of the satellite parameters.
At 03:50 PM 5/6/2007, Greg D. wrote:
I need a good uplink antenna for the new birds, and have no real space on the boom to add a yagi. This sounds like what I need; do you have any pictures? Also, more details on how you do the filtering to keep from frying the 2.4 preamp!
I have a screen-lined grill dish, with a canned helix feed to a Khune preamp. See: http://home.jps.net/~gregd/Dsc00201.jpg. Would I just put a single 1-wavelength loop around the outside of the helix at about the focal point? That would be right at the front of the
can...
Greg KO6TH
----Original Message Follows---- From: "kc6uqh" [email protected] Reply-To: kc6uqh [email protected] To: [email protected], [email protected] Subject: [amsat-bb] Re: loop yagis Date: Sat, 5 May 2007 23:19:29 -0700
Bob, For ATV I have used a Conifer BBQ grill type 2.4 GHz antenna with a Loop
for
1.2 GHz in front of the 2.4 GHz feed. The 1.2 side has plenty of return signal in the order of 18 dBi for ATV work. I haven't seen a loop yagi that will touch it in performance. I run full duplex with filters on both frequencies 1253.25 receive and 2441.5 transmit with 10 W. I am able to
work
the W6ATN repeater from 40 + miles.
Art KC6UQH ----- Original Message ----- From: [email protected] To: [email protected] Sent: Saturday, May 05, 2007 4:13 PM Subject: [amsat-bb] loop yagis
Hello What is the consensus regarding loop yagi antennas for L band uplink. I have 10 watts available from an IC1271 before the coax.
-- 73 Bob W7LRD AMSAT member 28498 Seattle _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
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73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep [email protected] ======================================
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