Paul,
My comment applied generally to VHF duplexers, which can be detuned by rough
handing. At UHF, you can use a "mobile" duplexer, which is far more
rugged. I was not thinking about GMRS being your intended application.
I don't think you need to employ a simplex repeater in this case. They are
great for allowing users to hear how they sound to others, but they quickly
become annoying to use. In some emergency situations, I can see a simplex
repeater being used on 2m, but only as a last resort. I have a Zetron 19B
"Simplexor" which I use for site testing, but it is no longer made, and the
other units are either far more expensive (being tactical communication
bridges) or woefully low in audio quality and features (Radio Shack).
73, Eric Lemmon WB6FLY
Paul Yonge wrote:
> On Nov 30, 2005, at 10:08 PM, Eric Lemmon wrote:
> > Bear in mind that when a duplexer leaves the factory with precisely-
> > set
> > tuning and insertion loss, it may suffer considerable vibration during
> > shipment. That's why I always check duplexers and bandpass
> > cavities on a
> > network analyzer before installing them. It's rare that such devices
> > arrive in perfect adjustment.
>
> Eric -
>
> Thanks for that observation about vibration. I'm planning for a
> mobile GMRS repeater in a Dodge Sprinter that is a great vehicle but
> does not ride smoothly on a rough road. Separate antennas won't get
> much spacing on a van roof. Since I'm envisioning relatively short
> messages (less than 30 seconds), maybe I should consider a "simplex"
> repeater with the received message being repeated on the same
> frequency after a time delay rather than on a different frequency.
> The duration of the time delay would be controlled by the signal from
> the lower-powered unit but not to exceed 30 seconds.
>
> Paul Yonge
> Syracuse NY
>
>
> Yahoo! Groups Links
>
>
>
>
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