VK3XX > PACKET 27.04.04 02:41l 99 Lines 5523 Bytes #999 (0) @ WW
BID : AF1312VK3XX
Read: GUEST DO9JPH OE5OJM
Subj: Comments on 9600bd packet comm
Sent: 040427/0132Z @:VK3FRS.#MEL.VIC.AUS.OC #:25852 [Kilsyth] $:AF1312VK3XX
To : PACKET@WW
In response to various questions raised in many recent bulletins I would
like to comment on my experiences with 9600 bd packet.
Firstly the 9600 interest in the early 90's was spawned by the satellite
fraternity and those setting up network linking and if you wanted to use
the then active 9600 bd satellites for message forwarding and downloading
then it required quite a bit of effort to get a system working. Many used
it very successfully until th demise of these satellites. However this
problem of 9600 bd was complicated by the need to have automatic tracking
antennas and automatic doppler shift to get any reasonable results.
I got into 9600 bd packet and modified a TS790A transceiver successfully
and commissioned a Paccom dual TNC called an NB96 which did both AFSK and
DFM (direct FM) which is the usual mode for 9600bd. I never did succeed
with the data satellites due to many site limitations here plus a computer
which wasnt really up to the automatic handling as mentioned above.
Around this time my then BBS obtained a 25 watt transceiver which had been
modified for 9600 bd and which he set up as a terrestial BBS port. He had
the same TNC as mine. The system worked great over a very poor 8 km path
with hills between us. He needed a very substantial gain vertical antenna
to cover the area and I was using a vertically polarised 16 el yagi at
very low height. We established a very reliable path for packet operation
on 70 cm.
The data flow rate directly into his 9k6 port was fully 8 times that for
1k2 packet. For about two years this was great and I never used 1k2 packet
in this period. However in 1998 my BBS sysop became seriously ill and
sadly died.I found another BBS with a port with 9k6 packet but I could not
get decent signal strength over about 35-40 km into his system as he was
only using about 1 watt for access to a high site node with a 70 cm port.
I could reach this node very well at 52 km from here. However the data
transfer going through this node droppped considerably and was much closer
to that on a direct 1k2 link.
Eventually this BBS closed for personal reasons and once again I was
searching for a new BBS. There was one reasonably close to me, the one
that I use for this 1k2 message. However, I have never had really good
results on his 9k6 1 watt port when he had one. I could use packet
manually but the auto systems like Winpack didnt seem to work as they had
with the others. Signals were just not robust enough. I learned years ago
that packet needed a robust radio link and was definitely a STROMG signal
mode if decent transfer rates were to be achieved! In the mid 80's I found
that 1k2 baud was woefully slow without a useful amount of power and a
good VHF antenna system with a properlow loss feed line (certainly NOT
RG58!) something which the newer packet operators dont seem to have
learned hence their disatisfaction with packet in general.
So now I have a nice 9k6 setup but no 9k6 access. My current BBS has a
good 70 cm 1k2 port which I use all the time now and get excellent data
transfer efficiency up to about 75 characters per second on download and
often 80+ on upload with a long PACLEN of 250 set which is acceptable when
the link is good enough to get VERY few retries. The download speed is
fixed by the PACLEN at the BBS which is set at 128 in many cases where 2
metre 1k2 port users have lots of retries due to QRM and poor radio links.
Our local BBS's often use this which commits both 70 cm 1k2 or 9k6 ports
to the same TNC settings.
So I ask the question as to whether the trouble necessary to set up for
9k6 is worth it for most users who just want to send a few messages and
read a few bulletins from a local BBS. The 9k6 node network no longer gets
any real use around here and is probably falling into disrepair. All
these issues cause disatisfaction with users who have gone to a lot of
effort to get 9k6 going so maybe it is time to encourage a renaissance in
9k6 among those that are now showing a little interest. Nothing will
happen without some more BBS's setting up usable 9k6 ports and nodes
which have reliable RF capability over reasonable distances.
The 9k6 system worked well 15 years ago but it sure is broke now even if
1k2 is still alive and well. Could this be that the newcomers to packet
are more computer oriented than radio oriented. There is nothing like an
interest in making a decent and useful VHF/UHF SSB radio station to learn
about haow to achieve decent signal levels over long radio routes. I
consider that lack of interest in this aspect of amateur radio is the
reason why packet is also dying in so many areas. The proper aprenticeship
in VHF/UHF communications is lacking due to the use of so many FM radios
with repeaters and internet talk links for amateur amateur talking. And
that isnt a typo back there.
So now I will get off my soapbox and see if this can stir up some
How many agree with me who are still out there in packet land and are
prepared to tell THEIR experience to the newcomers? I also pose the
question as to why there is such a rush for nominal speed. There are still
a few pactor, HF,bandwidth limited, links that can get your packet mail to
some overseas destinations as quick as a packet sytem using telnet to a
BBS and then the internet thereafter. Just how fast can you type???
73 - GORDON, VK3XX @ VK3FRS
Message timed: 11:08 AEST on 27 Apr 2004
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