[amsat-bb] Full Duplex Radios

Sigil caleriffic at paradise.net.nz
Tue Jun 2 02:03:45 PDT 2009


I have been trying to follow this confusing discussion about "Full 
Duplex Radios". It seems to me that different people are using the same 
term to mean different things.

Everyone seems to agree on the meaning of "Full Duplex" as the term is 
used when talking about Ham satellites and radios. It is a radio that 
allows you to listen on one frequency in a particular band, while 
simultaneously transmitting on another frequency in different band.

However, the phrase "Cross Band Repeater Mode" seems to have two 
meanings as it is being used on this reflector right now.

Meaning One: a radio the can be used with a cross band repeater 
somewhere. That is, a radio that can be set up to receive in one band, 
but switches to another band when the PTT is operated and the radio 
transmits. When this radio transmits, the receiver is turned off.

Meaning Two: a radio that can be configured to function as a repeater in 
that it retransmits the received signals in a different band. Naturally, 
it does this simultaneously. It is a Full Duplex Radio.

Most (all?) modern HF radios can do "Meaning One" (A/B VFOs, etc), as 
can many dual band UHF/VHF radios, so this is perhaps not particularly 
unusual. It might be better to reserve the term for those radios that 
can function as a repeater.

Sil - ZL2CIA.

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