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PA2AGA > HDDIG 10.11.99 12:30l 227 Lines 7717 Bytes #-9689 (0) @ EU
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------------------------------
Date: 9 Nov 1999 09:44:07 GMT
From: Hans-Peter Zorn <hpz@gmx.net>
Subject: German packet radio
Rob Janssen <nomail@pe1chl.demon.nl> wrote:
> On the user side, there are 70cm and 23cm designs, usually operating
> split-frequency with a duplexer at the repeater (for echo-duplex).
> But these are far less popular, because the average HAM prefers spending
> money on a slick Japanese trx that really isn't suitable for packet,
> instead of having a sheet-metal box that screams at 2-8 times the speed
> for half the price. Such is life.
This is currently changing, mostly because of the new T7F 70cm TRX which
is very popular at the moment. Today I would estimate that the AFSK
user access points are in the minority.
BTW, the limitation to 76k8 here is only due to the ancient RMNC controllers
which cannot do more than 76k8 even if overclocked to 16Mhz. The modems
and radios for 6cm can easily do some 100kbit/s. I suspect that if the
new RMNC design does not come very soon now, people will move to
other designs such as the new PCISCC card by dg1kjd which is said to
support some 10 MBit/s.
Hans-Peter DG4IAD
--
Hans-Peter Zorn, Karlsruhe, Germany
http://www.stud.uni-karlsruhe.de/~uhsm/ hpz@gmx.net (preferred)
http://1409.org/people/hp/ hp@1409.org (hamradio stuff)
>.
------------------------------
Date: Tue, 9 Nov 1999 03:45:18 -0600
From: "Charles Brabham" <n5pvl@texoma.net>
Subject: German packet radio
Hank Oredson <horedson@att.net> wrote in message
news:807fa2$9g$1@bgtnsc03.worldnet.att.net...
>
> I've watched this from the start, back when TAPR "promised" 9k6 gear
> to be available in 1985. Although a few of the RF engineering types seem
> to have done a good job designing some interesting gear, there has been
> essentially total failure making anything available commercially.
>
> I know a bit about RF design, although I've never done it for
> a living. Enough to understand that the problems are probably
> in the sales and marketing side and not the engineering side.
Side note: A member of my family designed and implememnted a 56 kb.
Spread -Spectrum cellular network five years ago from commercially available
equipment, off the shelf. During that first year, he had over 150 customers.
TAPR has been "developing" SS for over five years now, and has yet to market
one (1) usable unit to a Ham.
I guess that's why I, like most Hams, do not pay a lot of attention to TAPR.
> > Is it any wonder that radio networks are dying of old age?
>
> Yup. The lack of gear, and the ease of using the internet.
It's different in Europe. They have no TAPR there, but they do have several
small companies started up by Hams that produce usable digital equipment at
reasonable prices.
> > If we would stop pissing on each other, maybe we can get
> something
> > constructive done!
>
> No organization exists that could coordinate anything.
> Hardware, software, network infrastructure: nothing there.
Probably the single most successful program TAPR has ever gotten involved in
is the effort to hold back and retard US digital Ham Radio. They've done a
great job at that and a miserable job of doing anything else.
--
73 DE Charles Brabham, N5PVL
N5PVL @ N5PVL.#NTX.TX.USA.NOAM
http://www.texoma.net/~n5pvl
>.
------------------------------
Date: Tue, 9 Nov 1999 04:48:03 -0600
From: "Steve Sampson" <ssampson@usa-site.net>
Subject: German packet radio
Eric S. Johansson wrote
>> I would be more impressed if that 100 kHz was spread out over 4 MHz in
>> either a FHSS mode, or a DSSS mode. Legal on 70cm's.
>
>so would I. But we (as hams) can't even do the simple stuff let alone
the
>more complicated spread spectrum stuff.
Hogwash. Paccomm's been selling equipment for large bandwidth FSK stuff
for years. Not for $200 though, they aren't a charity.
>I would rather see stone stupid FSK 76k digital radios in many ham shacks
now
>than the very elegant, 1mb spread spectrum radios RSN!
The problem, as I see it, is that you can't just scale up the data rate and
be
effective. You are not going to go 10 miles with this bandwidth, without
stability
several orders of magnitude better than a stock crystal based oscillator.
>hells bells steve, then pull your thumb out and design a low cost (<200$),
70
>cm, FH spread spectrum radio that hops in between repeaters. Sure, it
will
>raise the noise floor but who gives a f*** if it's between repeaters,
nobody
>will notice. Since repeaters are idle most of the time, we should
have
>little or no collision problems.
$200?? Where did that figure come from? You want the moon, but you'll only
pay for a hub-cap? The reason they can sell a TV for $200 is that they sell
millions of them. There's only 100,000 Hams in the US. 15% which are maybe
interested in data networks.
>I'll even pull together a design team to design the network side.
There is FreeBSD, and Linux already. Networking is not the problem.
Pumping
data at over 1 Mbps is a hardware problem.
>this is so dammed frustrating. We could use a competitive network
to
>attract new people into the hobby and provide emergency communications.
We
>have the knowledge in the computer and networking side and the tools
are
>almost off the shelf but we can't get any RF people to help with the radio
side.
>Is it any wonder that radio networks are dying of old age?
The TAPR SS radio project is interesting to watch, because it brings example
solutions to hard problems of both the RF and the error detection and
correction.
OK, here's an RF project: Design a module that has four digitally
programmable
oscillators that can generate a carrier from 441 to 445 MHz in 10 kHz steps.
Each oscillator has to be stable and have over 60 dB of attenuation when not
selected. One oscillator is programmed with a synchronizing frequency.
This
oscillator is selected (say) 16 times more often than the other three. The
other
three are preloaded with the next hopping frequencies, and used round-robin.
The total switching time from one oscillator to the next is < 10 ms
(deselect one,
no carrier, select next), or however fast you can fill and switch each
oscillator
to the next frequency.
One oscillator design, duplicated four times.
The object would be to get the advantage of narrow-band in a high-bandwidth
product. High speed FSK is actually pretty hard to keep aligned. Any drift
at
either end, and the BER goes to hell in a hand-basket.
>If we would stop pissing on each other, maybe we can get
something
>constructive done!
I'm sorry if my posts seem to be just pissing. I intended only to discuss
the issue.
>.
------------------------------
Date: Tue, 9 Nov 1999 10:37:49 GMT
From: nomail@pe1chl.demon.nl (Rob Janssen)
Subject: German packet radio
Hans-Peter Zorn <hpz@gmx.net> wrote:
>This is currently changing, mostly because of the new T7F 70cm TRX which
>is very popular at the moment. Today I would estimate that the AFSK
>user access points are in the minority.
Same here, but the move has been mostly to 4k8/9k6, not to 76k8.
Only because standard Japanese transceivers can be sort-of made working
with that.
There is a local node that runs 38k4 on 23cm, but it has maybe 4 users...
To be continued in digest: hd_99_286C
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