[amsat-bb] Re: Educate the Manufacturers

Tony Langdon vk3jed at gmail.com
Thu Dec 16 17:46:50 PST 2010

At 12:11 PM 12/17/2010, Andrew Glasbrenner wrote:
>On 12/16/2010 4:47 PM, Trevor . wrote:
> >
> > Now it seems to me the Cross-Band Repeat facility wouldn't work 
> if it wasn't full duplex.
> >
> > 73 Trevor M5AKA
>Spot on. It has to be full duplex for cross band repeat to work, whether
>the guys who write the manual, marketing literature, or QST review
>realize it.

That's correct, except that the radio doesn't need to be able to use 
the mic or speaker while in crossband receive mode, so it is 
theoretically possible to have a crossband repeat capable radio 
without being able to make use of the duplex capability otherwise.

>I've never seen a radio advertised as full duplex, that wasn't. Even the
>G7 is, it just goes half-deaf. Non- full duplex rigs capable of
>reception of two bands at once are usually labeled as "dual receive".

Neither have I.  The manufacturers have been honest in this regard.

>Half-duplex is fine for getting your feet wet, but the increasing number
>of ops not moving up to full-duplex is having a real impact on the FM
>satellites over densely populated areas. Expense is no excuse. I've
>bought suitable uplink transmitters as cheap as $5 (IC-2AT), and the
>difference in an Arrow with and without diplexer is nearly the cost of a
>new simple 2m HT.

Agreed.  Once you go full duplex, you won't want to go back.  I've 
always done full duplex simply by using two separate radios.  That 
also makes tuning easier in the event you need to tune the uplink for 
Doppler correction.

73 de VK3JED / VK3IRL

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