Hi Martin and other AMSAT'ers, This is a bit beside the subject but I seemed to recall that OSCAR-III was running full duplex in the 2 metre band:
http://www.amsat.org/amsat-new/satellites/satInfo.php?satID=26&retURL=sa...
That is not on the same frequency - but the same band.
If you look at some systems like the Marisat system or some of the scientific satellites in the 2 GHz band it is the same.
To return to the subject I hope someone will gather all the information about full duplex transceivers that have been on the amsat-bb during the last days.
73 OZ1MY Ib ----- Original Message ----- From: "Martin" tmm@trutter.dk Cc: AMSAT-bb@amsat.org Sent: Tuesday, June 02, 2009 9:02 PM Subject: [amsat-bb] Re: true duplex radios
Hi Jim and others.
For ordinary Repeaters the Rx/Tx in the same band is mandatory. But just think of the filtering needed for TX'ing lots og watts just 600kHz away from your Rx-frq. This is also the reason why most repeaters (at least that I know of) uses really big cavity-filters.
But for Rx/Tx on the same frequency - Forget it. What would be the purpose anyway?
In my terms, a full-duplex radio is a radio that listens on one band, whilst transmitting on another.
Regards OZ1TMM, Martin
Jim Heck wrote:
Hi All,
In my experience, you dont have to listen to the output channal of a
repeater,
while transmitting to its input, ie you dont have to hear your own signals
coming
back through the repeater. BUT you do (ideally) when working through a
satellite.
Again im my experience, such a radio as Greg has described is called a
"half
duplex" one.
The big advantage of using a full duplex radio for satellites is that
you can
check if you are being rebroadcast by the satellite or not, without
relying on
others to tell you. (You can also change the polority of the up link
signal, for
maximium smoke!)
73 Jim G3WGM
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org]On Behalf Of Greg D. Sent: 02 June 2009 07:12 To: clintbrad4d@earthlink.net; amsat-bb@amsat.org Subject: [amsat-bb] Re: true duplex radios
{queue thunder clap}
Wait a minute... How can a radio be capable of cross-band repeat and not be full duplex? I believe the answer is no. Cross-band (analog) repeating is inherently full duplex. So, perhaps this is a simple way to ask a non-satellite person, without having to explain what duplex means.
By the way, my Alinco DR-610 mobile rig is also full-duplex. You may add it to the list. (In fact, it's got some down-right-weird modes, between the two sides of the radio, that it's sometimes anyone's guess what will happen when you key up.)
Greg KO6TH
From: clintbrad4d@earthlink.net To: amsat-bb@amsat.org Date: Mon, 1 Jun 2009 12:37:16 -0700 Subject: [amsat-bb] Re: true duplex radios
... Yaesu FT-8800 ...
Really? Dual-receive, indeed. And will perform crossband repeating. But I can transmit on one band and simultaneously hear myself on another with a FT-8800? _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite
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