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Re: Re: Discovery Project: Which Mission Next?



Hi Bob

>
> But in HAM radio, just extending one-on-one phone-line technology via a
> satellite could almsot be said has nothing to do with HAM radio.  I think
> that we should work for protocols that permit one to MANY on any given
> link.  So that many people can monitor digital QSO and join in if
> inteested.  That is kinda what HAM radio is all about.
>
> Pt-to-pt digital links we can do every day on the phone, and the internet.
> I hope we look for applications that let everyone "see" or "hear" what is
> on the high speed digital channel, and not just the 2 individuals at both
> ends.  We need to enhance our ability to let mltiple stations participate
> in most of our applications, not just provide more pt-to-pt phone lines...
> which just happen to be via P3D...
>
I think you're right. Genuine point to point with no means of interception
isn't at all what we're after. The IP/NetMeeting suggestion was just as a
way to see if it could be done using off the shelf stuff that we might
already have. It wasn't really a serious suggestion to use to get my end
result. I was hoping to use the learning from that to get something more
serious.

The point about full duplex was more that the setup time for small packets
on 9600 and the TX/RX switch is so long that most of your bandwidth
disappears. On full duplex, you could have the conversation going throughout
the whole information transfer without having to release the PTT. With a
broadcast style scenario we need to have a nice long-ish bursts (say 5 sec)
FULL of data. 'Normal' packets are only in the region of a second or so with
a 1000 byte MTU size. Perhaps we need more of a UDP style rather than TCP.
But that's not to say IP is the way! Sorry, my AX25 knowledge is
insufficient to comment on an equivalent in this protocol.

Better would be, I guess, to unshackle ourselves from strict adherence to
such protocols and do something similar to the PB broadcast.

Anyway, I spent the last three hours or so fiddling around with various
radios and TNCs to see if I could get the netmeeting thing to work between a
couple of computers, but it appears that my 9600 bps connections are rather
flaky under IP even though they seem OK on AX25 on the digi birds.

It's going to take a bit more fiddling about to get this thing to work at
all. I think that even though my rigs were but feet apart, there's so much
computer RF generated in the shack by this hacked together setup that the
poor radios (using rubber ducks inside the shack) ain't having it. Two of
them (a TH-D7E and a TM-D700E) were only breaking squelch occasionally when
a packet was sent. My FT-847 and a Paccom NB96 TNC with external antenna
were much better behaved.

Also, the D7E has no hardware handshake so that may have been a problem too
at 9600. Anyone know how to make the data ports on the D7 & D700 work higher
than 9600? Also, can you make either rig TX when the squelch is open but no
data's arriving, like a true DCD detect? Either that or I'll wire up my old
MFJ 1278B which has a 9600 bps modem in it.

73 Howard G6LVB

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