REFLECTOR: Transponder Antenna

[Keith Hallsten]

Larry,

Actually, that's an "Old Wives Tale".  The output that's significant for
biological effects is the average output, which is very low for the
intermittent broadcasts of a transponder.  Transponders are rated on their
peak output, which looks like a scary number.

I am not going to loose any sleep because I located the transponder antenna
fairly close to my body.

The high frequencies used by transponders make the line losses significant,
so it's best to keep the antenna feedlines as short as possible and also to
use a low-loss type of coaxial cable, such as RG-400, rather than the old
RG-58.

Regards,

Keith Hallsten


-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of lawrence epstein
Sent: Wednesday, August 15, 2007 3:41 AM
To: reflector at tvbf.org
Subject: Re: REFLECTOR: Transponder Antenna

I have heard repeatedly that teh Transponder is a high output transmission 
and the antenna should be located as far away from the occupants as 
possible.

Larry E.


>From: "Emanuel Lewis" <elewis8 at nycap.rr.com>
>Reply-To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>Subject: REFLECTOR: Transponder Antenna
>Date: Wed, 15 Aug 2007 05:45:04 -0400
>
>O 540I wrote a few weeks ago asking about best location for a transponder 
>antenna.  I have a new "sharkfin" type antenna I plan to locate under the 
>copilot seat.  Does anyone have information/experience about the difference

>in performance if the antenna penetrates the fuselage so that its surface 
>is outside vs. mounted inside the fuselage?  Also, how about the size of 
>the aluminum plate that serves as a ground plane?
>Thanks,
>Manny Lewis


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