I have just been involved with the sats since February and also wanted an omni for base station use. I started with a simple 1/4 wave ground plane (19" for 2m, 6 1/2" for 70 cm), later tried homebrewing Jerry's Eggbeater II, and then bought a second-hand M2 eggbeater and the ARR preamp. I noticed little or no difference between the 3 antennas, certainly not enough to justify the relatively high price of a new M2 eggbeater. The preamp helps a lot but, as Jeff says, SO-50 is still quite weak.
Have not tried the Lindenblad. Not many are using it or talking about it, so I doubt it is all that great. Same for the turnstile.
I do far better with a 5w HT and a handheld Arrow than I do with an IC-7000, ARR preamp, and any of the omnis I have tried. However, unlike some people, I don't really enjoy standing in the yard holding the Arrow antenna for 15 minutes. So I usually work from inside.
If you do go omni, get it high enough to be in the clear. And unless you get a preamp, use very good coax and keep the line as short as possible. You can get a 70cm receive-only preamp from Ramsey Electronics for $17, but with that you'll need a separate coax line for the 2m uplink, or a duplexer. The ARR is the cheapest RF switching preamp and it's over $125.
I also homebrewed one of Kent's dual band LEO cheap yagis, see http://www.wa5vjb.com/references/Cheap%20Antennas-LEOs.pdf. It can be built for $10 and it works as good or better than the far more expensive expensive Arrow, although it's not quite as portable. As Jeff mentioned, the Arrow unscrews into very small pieces and fits in a suitcase, very nice for air travel. The cheap yagi elements are glued to the wood boom, will fit into a car trunk but is not suitable for air travel, unless someone comes up with a different way to attach the elements to the boom that allows easy removal.
Have not tried this, but I'm almost certain that a cheap yagi mounted at a fixed 20-30 degree elevation and rotated with an old TV rotator will be less expensive and give substantially better results than any omni, even an omni with a preamp.
Good luck and 73, Bill NZ5N ********************************** Date: Thu, 27 Mar 2008 07:37:20 -0700 From: Jeff Mock [email protected] Subject: [amsat-bb] Re: Easy to make, low cost omni-directional antennae To: Graeme Nelson [email protected], "'AMSAT-BB'" [email protected] Message-ID: [email protected] Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi,
I'm new to satellite stuff and I had essentially the same requirements as you. I live in a dense urban environment so I have more QRM problems than most, limited roof space, and I try to keep a low profile and not get the neighbors too excited.
I wound up purchasing two eggbeaters from M2, one for 70cm and one for 2m: http://www.m2inc.com/products/vhf/2m/eb144.html
They work well, they are well-built, and are great for AO-51, ISS-digital, and GO-32. I also wound up getting an ARR masthead preamp
for the 70cm eggbeater to compensate for my long feedline to the roof http://www.advancedreceiver.com/page10.html
To tell you the truth, the two eggbeaters are marginal for me working SO-50. It is just above the noise and I don't feel like I hear it well
enough to transmit. If you want to listen for weak signals you might go straight to a directional setup with more gain. I feel a rotator in my
not-too-distant future...
Eggbeaters aren't terribly portable. The copperweld loop is going to spring loose when you take it apart and poke someone in the eye, so I don't move them. For portable I got and Arrow-II handheld 70cm/2m yagi. It's great fun and seems to be popular. I used it with an old Icom-W32A HT on vacation and used it to work AO-51. It breaks down really small,
fits in a little bag, and I can put it together in less than 5-minutes: http://www.arrowantennas.com/146-437.html
jeff AD6EO
Graeme Nelson wrote:
Hi all,
I'm wanting to make an antenna for "talking with the
birds", mainly ISS and
LEOs. Thank you to Don ZL1THO and John KB2HSH for
the suggestions and
encouragement they have already e-mailed me.
I have done some more thinking since then and come
up with the following list
of criteria for the first antenna I make for
satellite work:
- easy to make
- lost cost
- omni-directional
- good performance, especially for satellite work,
without moving it
- portable enough that I can pack it into the van
when I go on holiday and it
won't take up much space (it needs to share the
space with all the stuff for
my wife and 3 children, as well as me). It would
also be nice to be able to
store it in the corner of my office at work if I so
desire.
When I started looking in earnest last Friday, a ham
colleague of mine did a
Google search an came across a turnstile antenna
that looked promising
evening, I noticed the
eggbeater on the web site of John KB2HSH
(http://kb2hsh.blogspot.com/), which
looks nice and easy to build. I then did some
searching and came upon the
Eggbeater II by Jerry K5OE
(http://members.aol.com/k5oejerry/eggbeater2.htm),
arguably a better fixed antenna for satellite use
than the original eggbeater.
A while later, I also found the EZ-Lindenblad by
Tony AA2TX
(http://www.arrl.org/qst/2007/08/monteiro.pdf).
I am currently leaning towards the EZ-Lindenblad
(for 2m) and a parasitic
Lindenblad (for 70cm ... when I get hold of the
design; I intend to e-mail
Tony about it if/when I go ahead with the
EZ-Lindenblad).
How do these antennae compare performance-wise? Am
I leaning in the right
direction (EZ-Lindenblad), or should I be looking at
something else? Your
input would be much appreciated.
TTFN., Graeme ZL2GDN
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