Comm noise

Yup, and typically you shut one transceiver off (in the RF sense) and
connect the antenna directly to the other transceiver with a switch. Both
this technique and the duplexer are rather difficult to achieve when you are
talking ten watt transceivers being isolated in a small device from a
microvolt receiver. For years hams have used coaxial switches to switch
antennas between HF rigs, but doing it at VHF presents its own set of
technical problems. Google Dow-Key to see the moosieness (?) of a coax
switch.

Jim



A Nav only antenna doesn't transmit, which is why they can be shared
easily. It's possible to share comm antennas, but you need either a
transmit switch or duplexer of some type to protect the receiver.

"RST Engineering" wrote in message
m...
Yup, and typically you shut one transceiver off (in the RF sense) and
connect the antenna directly to the other transceiver with a switch. Both
this technique and the duplexer are rather difficult to achieve when you
are talking ten watt transceivers being isolated in a small device from a
microvolt receiver. For years hams have used coaxial switches to switch
antennas between HF rigs, but doing it at VHF presents its own set of
technical problems. Google Dow-Key to see the moosieness (?) of a coax
switch.

The FAA does it on the other end on the same frequencies. The actual device
that does it is not very large either. It's about 2-3" square and about an
inch tall. I've never seen it on an airborne application, but that's not to
say it isn't practical or even that it hasn't been done. Personally I
wouldn't want it as it just gives you another few single points of failure.
I'd rather have two antennas and two sets of cables.

"Mike" writes:

I'd rather have two antennas and two sets of cables.


Agreed, especilly for a hand-held. Add an antenna for it, period.
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

"RST Engineering" wrote

Google Dow-Key to see the moosieness (?) of a coax switch.

I see all kind of neat products there, but I still don't understand what you
are getting at, as far as moosieness (whatever that term is or implies) and
its relation to a coax switch.

I know I shudder every time I contemplate having to make up a well and
properly shielded connection. I would assume that is the direction you are
going, with trying to keep the correct clearances between the conductor and
the shield, with all of the components in a switch, and still be well
shielded.

Or not? g
--
Jim in NC