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Re: Re: [sarex] Why FULLDUPE On is good? (Re: iss)



On Mon, Apr 16, 2001 at 10:00:03AM -0600, Vince Fiscus, KB7ADL wrote:
> I know Bob APR disagrees, but the TNC on the ISS won't transmit until the 
> uplink frequency is clear.  This is built into AX25 to prevent packet 
> collisions. Since the ISS is transmitting on a separate frequency there is 
> no need for it to wait as its packets won't be colliding with anyone 
> else's. The result of all of this is that we get more packets from the 
> ISS.  With full duplex on, the ISS will transmit even if DCD on the uplink 
> channel.
> 
> More packets being digipeated is good. I suspect most of the congestion on 
> the ISS uplink right now is just hams trying to get one CQ packet 
> digipeated. Once a station gets its packet digipeated that station will 
> probably stop trying to digipeat while they wait for a response from a 
> fellow key-boarder. No one likes to send or see the same thing digipeated 
> over and over again (except APRS and un-attended beacon operators.)

At the same time, less packets will be received because the
actual radio is not operating full duplex and can't listen
while it's transmitting (I would assume).


Hamish
-- 
Hamish Moffatt VK3SB <hamish@debian.org> <hamish@cloud.net.au>
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