Just remember the antenna should have a ground plane (not sure of the exact
dimensions) but ours is about 12"" diameter, kitchen foil spray adhesived to
the fuaelage belly (near the tail end). Aerial was a sharksfin shape from
Aircraft Spruce.
Additionally, if you mount the aerial near the occupants you will be
subjecting yourself to continuous radiation (unlike the comms radio which
only transmits intermittently, the transponder transmits every second and at
a higher output wattage). If you are planning on fathering any children this
is something you should consider (on a metal A/C this dosent matter because
you are shielded but in a plastic A/C there is no shielding). In other words
it would be better to mount the aerial near the back end of the A/C. If you
do this however you will need to use lower loss (ie: larger diameter)
coaxial cable).
----- Original Message -----
From: "M@nsfield" <nsfield@screaming.net>
Subject: Europa-List: Transponder antenna
>
> Planning what transponder antenna to fit and where... I want to avoid
> putting
> it exposed under the belly.
>
> My likely choice is a Microair T2000 and I would like not to have to
> spring
> for a Bob Archer ($$$), but am told that the stub antenna must (should?)
> be mounted externally.
>
> I've read everything I can in the archives, and asked the UK supplier of
> the Microair, and still get several different answers.
>
> Jim Nelson wrote on 20 Jan 2004 "I mounted mine in the back on the pilots
> side. I mounted it vertical on three wooden rods which were reduxed to
> the
> fuselage. Ran the coax up the pilots side just under the door jamb and on
> to the transponder. Seems to work fine. No interferance or noised
> noted."
>
> This seems the logical answer, is this the stub (2.5"?) antenna & can you
> elaborate on the 3 wooden rod mount, please Jim?
>
> Anybody know why I shouldn't mount the stub antenna internally (glass is
> transparent, isn't it?) behind the baggage bay, without being too far from
> the xpdr unit and without degrading the signal significantly?
>
> Any other helpful, cheap, suggestions, please?
>
> Paul M
> Mono XS 383
> CM etc in, top on next
>
>
> Book yourself something to look forward to in 2005.
> Cheap flights - http://www.tiscali.co.uk/travel/flights/
> Bargain holidays - http://www.tiscali.co.uk/travel/holidays/
>
>
>
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