[chirp_users] ? re 'duplex' field

Tom Hayward esarfl at gmail.com
Thu Jan 2 09:43:33 PST 2014


On Wed, Jan 1, 2014 at 11:02 PM, Benton Holzwarth <bcgh at aracnet.com> wrote:
> I'm helping organize a base set of frequencies -- a 'standard load' --
> for our local CERT group, Tigard, OR.  I've read a ton of posts and come
> up with a base set of guidelines that I'm hoping will cover the 'least
> common denominator' radio that someone might show up with.
>
>    o Don't use row zero, some radios start at row-1
>    o Hold to 5 characters for the memory 'name'
>    o Include the FRS and official frequencies as Rx only
>    o Different radios have different numbers of memories, pack the
> highest priority bits into the lowest memory-rows.  Some radios stop at
> 16 memory-rows, others go to 100 or 128

Seems like a good set of criteria.

> We'd like to load some Rx-only frequencies -- FRS, the local police
> forces and ambulance service that use UHF, but in Rx-only.  When I set
> 'duplex' to 'off' Chirp says something about not all radios support this
> setting.
>
>    o Is there a list of radios that do support?

As others have mentioned,
http://trac.chirp.danplanet.com/chirp_daily/LATEST/Model_Support.html
shows the list of duplex options for every radios.

>    o If I try to program duplex-off into a radio that doesn't support
> it, what is the reaction from Chirp?  Does it let me know there's a
> problem or just gloss over and make those frequencies tx-able?

When you import a duplex-off channel into a radio that doesn't support
it, it defaults to "none" (simplex).

Typical ham radios do not have a per-channel TX inhibit feature, but
do prevent transmitting outside the ham band. In the case of an
unmodified Kenwood, Icom, or Yaesu ham radio, settings out-of-band
channels to simplex will still prevent transmitting. All bets are off
if the owner modifies their radio for out-of-band transmit.

> I'm trying to figure out how best -- across a wide field of radios -- to
> manage a set of frequencies that should be Rx-only.  Duplex
> off/split/offset  One solution seems to be to dial in 'split' pointing
> the tx-side to a harmless corner of the Amateur band.

Blindly transmitting into the ham band isn't harmless! You could
interfere with a ham. That ham probably doesn't have lights on their
car and carry a gun and handcuffs, but you never know. ;-)

Tom KD7LXL



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