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Re: Eggbeaters ?



At 12:58 PM 12/3/2005 -0700, Jason Hitesman wrote:
>Dave Hartzell wrote:
>> Hello,
>> 
>> I'm curious about anyone's experience with eggbeater antennas for  
>> working the sats.  I have a limited-space situation (apartment) which  
>> makes a steerable yagi difficult.
>> 
>> M^2 Inc. has 2m and a 70cm models, but go for over $200 each.
>> 
>> Since I'm new to the sats, I'd probably be working with two  handhelds, 
>> which have been (at best) OK in conjunction with my Arrow....
>
>And friend and I both built eggbeater style antennas from K5OE's plans:
>http://members.aol.com/k5oe/eggbeater.htm
>
>He runs a pre-amp on his and has had fairly good success with it for 
>recieving LEO FM sats.
>
>I don't have a pre-amp and have not had as much luck with mine.  I have 
>managed to hear bits and pieces of AO-51 high power passes and high 
>angle AO-27 passes.  But nothing that was clear enough I could work the 
>passes.  Not sure how well my version compares to the commercial antenna 
>but without a pre-amp I've found to not be very suitable for sat work.
>
>I've started building one of G0MRF's 440 pre-amps:
>http://www.g0mrf.freeserve.co.uk/432LNA.htm
>
>Unfortunatly all of my drill bit sets are missing their 7/64's bits so I 
>haven't been able to wind the inductors yet :(  One of these days I'll 
>remember to pickup a new drill bit set and finish this thing and see how 
>the egg does with a little bit of pre-amplification.
>
>I've had much better luck with my homebuilt Yagi's first one from K5OE's 
>plans and then another from VE6AB's plans:
>http://stormchaser.cjb.net/
>
>I also built a copper cubic loop antenna from a QST article a year or 
>two back which the author claimed to have used for AO-27 fairly 
>well...but I can't get mine to tune up very well at all.  I suspect the 
>problem is with the dielectric I'm using in the match - I need to find 
>some of the right teflon to finish it up.
>
>I'm also considering building one of the corner reflectors described in 
>the latest AMSAT journal since I'm getting tired of the looks my 
>neighbors give me when I stand outside waving my yagis around.  I'm 
>ready to start doing sat contacts from inside instead :D  I may do 
>another VE6AB style Yagi on a TV rotator...but I enjoy building antennas 
>  so the corner reflector sounds like a fun experiment!
>
>Photos of my various antenna attempts are up here:
>http://jhitesma.smugmug.com/Electronics
>
>----
>Jason Hitesman
>N8INJ
>----

Jason, Dave and others:

Having a long history with operating satellite (since AO-7's launch) I
would like to add my two-cents.  Initially on launch I copied AO-51
telemetry using a 3/4 WL magnet-mount mobile whip stuck on a 12-inch ground
plane (steel sheetmetal) set on top of my roof.  I connected a 432-MHz
preamp at the antenna and that worked quite well down to 10-deg. elevation
(probably where the tree line was).  I have not operated normal FM through
AO-51 so have not hands-on knowledge on what is best, but...

I suspect for reliable operation on AO-51 one needs a little gain in the
antenna beyond that provided by a vertical or eggbeater.  I concur that one
should build a K5OE potato masher instead of paying big bucks for an M2
Eggbeater.

Instead I would go with a small yagi or the corner reflector pointed up at
15-degrees (or so) and rotatable in azimuth.  If using linear polarity it
probably matters little if you chose Vertical or Horizontal so pick what is
easy to construct.  This will satisfy most of the passes one gets.  See Bob
Bruninga's rotator control and write-up using only azimuth rotation.  This
is KISS!

I have a bigger full az-el system of antennas but that is just "icing on
the cake" for operating the Leos (it will come into good use for Heo's like
P3E, though).
73's,
Ed - KL7UW 
===================================
BP40iq,  Nikiski, AK      http://www.qsl.net/al7eb
Amsat #3212
Modes: V - U - L - S
===================================
----
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