Easy to make, low cost omni-directional antennae
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 (http://www.wb8erj.com/turnstile_antenna.htm). That 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
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 (http://www.wb8erj.com/turnstile_antenna.htm). That 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 _______________________________________________ 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
Since I didn't pick the correct numbers for last week's big Mega Millions drawing, I am again looking for cheap equipment.
I remember seeing a home brew "relative" noise figure meter somewhere. It would not give you an absolute noise figure number, but it would move a needle one way or another to show how your tweaks are affecting the noise figure of the device under test.
Does anyone know what this is or where I can find a link to it?
Thanks, Tyler KM3G
----- Original Message ----- From: "Tyler Harpster" tyler881@comcast.net To: amsat-bb@amsat.org Sent: Friday, April 04, 2008 4:39 AM Subject: [amsat-bb] relative noise figure meter
Since I didn't pick the correct numbers for last week's big Mega Millions drawing, I am again looking for cheap equipment.
I remember seeing a home brew "relative" noise figure meter somewhere. It would not give you an absolute noise figure number, but it would move a needle one way or another to show how your tweaks are affecting the noise figure of the device under test.
Does anyone know what this is or where I can find a link to it?
Thanks, Tyler KM3G
Hi Tyler, KM3G
Here is the description of a serious and simple Noise Figure Meter that you can build with easy
http://gref.cfn.ist.utl.pt/cupido/noisefm.pdf
And here is the schematic diagram
http://gref.cfn.ist.utl.pt/cupido/nf_sch.gif
I use this Automatic Noise Figure setup with success.
73" de
i8CVS Domenico
participants (4)
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Graeme Nelson
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i8cvs
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Jeff Mock
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Tyler Harpster