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Re: Why FULLDUPE On is good? (Re: iss)



At 05:52 PM 4/16/01 +0900, Yoshihiro Imaishi <imaishi@aa.mbn.or.jp> wrote:
>Hello all. This is Yoshi.JF6BCC.
>
>   I saw some articles on this list same as above. But I could not
>understand the advantage of FULLDUPE ON.

Full duplex on, will only be an improvement for the ISS TNC, not your own 
personal TNC. For your own TNC leave full duplex off.

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.)

kb7adl

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