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
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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 program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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