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Re[2]: circular polarized Arrow antenna

Hello Glenn,

Wednesday, January 30, 2002, 4:02:04 PM, you wrote:

GL> I want one of those quarter wave antennas!  50 watts into 10dB gain =
GL> 100 watts.  I would love to get a quarter wave antenna with a 100dB
GL> gain!

GL> 73
GL> Glenn

Not considering your math error you seem to mis the point completle
Joe was talking about the front to back ratio, not the gain.
A directional antenna has mutch less power radiating from the back than from the
front so don't be surpriced if you end up with less power hitting your
boddy with 50 watt in an Arrow then with 5 watt in a 19" whip,
especialy if you use the buildin mike of you HT.
When considering health risks with RF you got to stop thing in
absolutes and start thinking in relatives.
It's not about the amount of power that leaves the antenna in the
direction of the sat but the amount of power hitting you boddy
compared to a "normal" situation and the place the power hits you.

GL> -----Original Message-----
GL> From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org] On
GL> Behalf Of Gary "Joe" Mayfield
GL> Sent: Wednesday, January 30, 2002 8:13 AM
GL> To: Greg D.; amsat-bb@AMSAT.Org
GL> Subject: Re: [amsat-bb] circular polarized Arrow antenna

GL> What is the claimed front to back ratio?  50 Watts into an antenna with
GL> a 10
GL> dB front to back ratio is the same as 5 Watts into a quarter wave.  Just
GL> be
GL> clever enough to stay behind the antenna, and holding it away from your
GL> body
GL> might be a good idea as well.  If you have a hand held it is probably
GL> much
GL> worse at full power.

GL> 73,
GL> Joe
GL> ka0yos@amsat.org

73 de Andre PE1RDW
aprsdigi coördinator Netherlands
member aprsworkgroup Netherlands

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