In my own installations and the ones I illustrated on my website with the
rubber duck antenna's these were of course done with the 121.5/243.0 ELT's
not with 406 Mhz....
granted, few S&R teams have capability to even search the 406 frequency
signals and do rely on the stand-by 121.5 Mhz ....the new 406 ELT's
typically will no longer have 243.0Mhz but retain 121.5.again, you have to
have an external antenna or portable antenna to Tx on this
frequency.....Kannad does have an optional antenna for portable use and it
is possible that other rubber duck antenna could also be mounted to the unit
for 121.5 but Kannad warns that an improper antenna used here can also harm
the ELT...I'd need to get more clarification as to why and how but at least
their own portable antenna option remains as possible choice.
best regards
Tim Mara
Please visit the Wings & Wheels website at
www.wingsandwheels.com
"Darryl Ramm" wrote in message
...
Mmmm thanks Tim, that Kannad antenna systems is quite appealing for
somebody who really wants a 406 Mhz ELT. This may be by far the best ELT
approach, say mount it under the fiberglass RF area of a turtledeck (an
area that likely survives impact well).
Just be aware that many SAR organizations may still attempt to do final
homing on the 121.5 MHz beacon all these systems also carry and so having
a way to connect the 121.5 MHz antenna (if you are able to after
landing/crashing) is important. The 406 MHz patch antenna is unlikely to
provide a good radial pattern for ground based homing on 405 MHz.
I think we'll disagree on how reliable ELTs activations are - at least one
benefit of a Kannad system is that mounted like above or in front of the
spars under the turledeck and aligned along the gliders axis properly etc.
is likely a better install location than other places where these ELTs end
up misaligned and have likely lower probability of proper activation.
The problem with rubber ducky antennas with 405 MHz ELTs is having a
single antenna that handles 406 MHz and 121.5 MHz signals.
Darryl
On 8/24/11 1:54 PM, Tim Mara wrote:
Please look at my website page:
http://www.wingsandwheels.com/elt_em...plb_person.htm
there is a new unit from Kannad that has not only internal GPS but also
includes and internal 406 Mhz antenna. You will note that they originally
had suggested this could be mounted without any external antenna but the
FAA
frowned on this and they now include a note regarding this "an external
antenna must be mounted when "mandated".essentially though, an ELT is not
"mandated" for gliders and in fact there is an exception to the ELT
requirement for gliders. With that being said, this ELT can legally be
installed in a glider without the external antenna.....I have spoken
directly with our technical contact at Kannad and he stated that the ELT
performs as well with the internal antenna as with the external antenna
as
long as the ELT has an unblocked view (meaning not covered by metal,
carbon
fiber or materials that would otherwise block the antenna signal. The
other
exception to this is that the Integra ELT does not transmit the 121.5 Mhz
signal without the external antenna. It will Tx on 121.5 however with the
"portable" antenna used like most handheld devices so this could also be
easily implemented.
I have in the past installed the previous model 121.4/243 ELT's in my own
gliders with simple rubber duck handheld antennas since they too were 1/4
wave and typical for the airband (118-136 Mhz) and mounted these on
smaller
ground planes..Understandably even the short rubber duck antenna is in
actuality a 22-23" antenna but coiled so it in all perfection should have
a
ground plane that would be undoable in nearly any glider (being nearly
22"
radius) but even a small ground plane is more effective and though a
compromise of the "ideal" works....I have tested my own and found then
working and sending a signal that I believe could be received by S&R.
The big advantage to the aircraft ELT over Spot's and PLB's is that they
are
activated on impact and have internal batteries capable of sending the
signal for several hours even days and I know we've all heard the
arguments
that ELT's don't work....but the fact of the matter is that they do and
even
in soaring we have had ELT's that have helpd to find downed gliders..
should
ELT's be mandatory in gliders, in contest? or? ? I'll let the rest of you
argue and debate this and leave requiring ELTs, PLB's Spot's, Flarm,
TCAS
and the rest up the individual pilots to decide.
regards
Tim Mara
wrote in message
...
A couple of years ago there was talk of denying entry in to contests
all gliders that were not equipped with ELT's. I immediatly ordered a
121.5 / 406 Mhz model. It came the other day, a year and a half
later. It includes a clunky antenna that would have to be mounted
outside of a carbon hull. I have two questions. One, what happened
to the urgency??? and two has anyone come up with a workable solution
to the antenna issue?
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