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Re[2]: re 10m antenna for downlink



1005/frequency in MHZ

Danny
KE4RAP



Monday, June 14, 2004, 11:03:29 AM, you wrote:

RJ> Anyone remember the formula for calculating a full wave loop?

RJ> 73 de N8AU, Jim in Raymore, MO

RJ> -----Original Message-----
RJ> From: owner-AMSAT-BB@AMSAT.Org
RJ> [mailto:owner-AMSAT-BB@AMSAT.Org] On
RJ> Behalf Of Glen Gardner
RJ> Sent: Sunday, June 13, 2004 11:19 PM
RJ> To: amsat-bb@AMSAT.Org
RJ> Subject: [amsat-bb] re 10m antenna for downlink

RJ> I've had very good luck with a full wave horizontal loop antenna for use

RJ> with 10M downlink on LEO satellites in the past.
RJ> Put a 1:1 balun on it and use a Q section of 75 ohm coax (full wave loop

RJ> is around 90 ohms impedance) to get a good radiatin pattern and to get
RJ> the impedance down close to 50 ohms and it works well. It will be 
RJ> omnidirectional in the horizontal plane and the height above ground can
RJ> be adjusted to give  nice cardioid pattern upward for high eleivation
RJ> passes.  About 8-10 feet off the ground is fine.

RJ> I had one in the rafters of my garage in Michigan, and I was quite
RJ> pleased with the performance.


RJ> At present, I'm using a dipole made from helically wound CB trucker
RJ> antennas (which I bought at radio shack a long time ago) and a home made

RJ> balun.
RJ> It works rather well , but does not have the pickup efficiency of a full

RJ> wave loop due to the small surface area ofthe dipole.



-- 

Danny


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