I wonder if owners of other similar radios have similar problems? I have not
heard of a requirement for such a large ground plane from other
manufacturers. Previously I have heard recommendations of 6" or 8" diameter.
On flexwing trikes we use a piece of expanded aluminium mesh about 10" x 8"
and it appears to work fine with a very low power Icom handheld?
Jerry
Obviously I don't have a problem on my carbon fuselage (just kidding).
LTS@avnet.co.uk
http://www.avnet.co.uk/touchdown
----- Original Message -----
From: Alan Stewart <alan.stewart@blueyonder.co.uk>
Subject: Unreliable Terra TX760 transceivers.
>
> The following is a response I received from Trimble, regarding
> intermittent problems with the Terra 760D tranceiver installed in
> my Europa.
>
> It may be of some relevance to all of you with Terra kit in composite
> aeroplanes. It does support a previously aired theory, and there is
> indeed a section in the installation manual, as the respondant states.
>
> My regret is that I wish I had known this before purchasing the equipment.
>
> Perhaps it offers some hope though, if someone can figure a way to fit a
> 42inch ground plane inside the fuselage.
>
> Perhaps, I should have bought an AWACS !
>
> Alan
>
>
> cc:
>
>
> Subject: RE: Unreliable Terra TX760 transceiver.
>
>
> Mr. Stewart
> Unfortunately without an adequate ground plane the 760 will not work,
hence
> your "aircraft orientation" symptoms, this is due to loss of omni due to
> lack of a ground plane.
>
> As stated in the 760 install manual paragraph 2.3.3, "a minimum of a 42'
> diameter circle with the antenna at center" is required.
> Also the base of the antenna must be bonded to the ground plane.
>
> There may also be leakage at the coaxial connections, the coax connection
at
> the rear of the 760 mounting tray and at the antenna should have a minimum
> of dielectric exposed, too much exposed dielectric and the RF energy will
> short to the coax shield and thus you have no transmission range and your
> audio will sound weak and garbled to the tower or receiving station.
>
>
> Regards,
> Tech. Support
> EMAIL: aerospace_techsupport@trimble.com
> > .
> >
> >
> >
> > -----Original Message-----
> > From: Alan Stewart [SMTP:Alan.Stewart@marconi.com]
> > <mailto:[SMTP:Alan.Stewart@marconi.com]>
> > Subject: Unreliable Terra TX760 transceiver.
> >
> >
> >
> > Dear Sir/Madam,
> >
> > I own and operate a Terra TX760 tranceiver in my Europa composite
kitplane
> > here in the United Kingdom.
> > The Terra Radio is unreliable on transmit. Sometimes I can transmit up
to
> > 30 miles or more, on other occasions, selected destinations have
> > difficultly picking up my transmissions from less that 100 yards ! Often
> > this improves dramatically when the aircraft orientation changes. The
> > destinations are frequently high quality airway radio equipment. (e.g.
> > London Information)
> > The equipment is useable, but unreliable. I know of many others with
> > similar problems with their Terra equipment.
> > Do you offer a solution to this problem ? I am aware that because my
> > aircraft is plastic, it is difficult to offer a wide 'ground plane' for
> > the antenna.
> > However, my wide band Icom A20 handheld transceiver does not suffer any
> > problems
> > !
> >
> > Thanks in advance for any service solutions you may offer.
> > Regards,
> > Alan Stewart
> >
>
>
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