Thanks for all the tips folks.
I will track down an SWR meter and check out the system.
I will let you know how I get on.
BW
David
On 29 mai 11, at 12:13, Frans Veldman wrote:
> >
>
> On 05/28/2011 11:09 PM, Bud Yerly wrote:
>
>> First check and ohm out your radio connections and coax attachment to
>> your antenna. Check out the coax that the center wire and outer
>> shield
>> have no continuity.
>
> All too complicated and not necessary. Just borrow an SWR-meter, and
> see
> what it says. Broken wires, shorts, resonance problems, everything
> shows
> up with this simple test.
>
> There are many radio amateurs, find one and he probably loves to
> look at
> the installation of a real airplane.
>
> If there is anything else than the Europa recommended halve wave
> antenna
> in the tail closeout, I would scrap it and arrange such a halve wave
> antenna. Contradictory to common believe fed by marketroids, there is
> nothing that beats a simple halve wave dipole for this application. No
> antenna can have any gain over a dipole without introducing losses in
> some area's. It is just like a light bulb, any gain you derive with
> reflectors and lenses will introduce dark spot in other directions. A
> half wave is close to omnidirectional and only has two small "dark
> spots" straight up and straight down. Fortunately if you are
> overhead an
> ATC facility the "dark spot" is of no consequence as you are pretty
> close anyway.
> There is another reason to stay with a dipole: A dipole has a certain
> impedance and it is exactly this impedance (50 ohms) that became the
> standard for the coax and output of the transmitter. Of course this is
> no coincidence as the manufacturers know that the dipole is the best
> solution. Other antennas might have a different impedance, need a
> matching network (often built in and invisible to the user), and often
> this matching network (consisting of coils and capacitors) breaks
> down,
> causing all sorts of problems.
>
> Just my 2 cents,
>
> Frans
>
>
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