A couple of decades ago, the "GRAPES" WA4DSY 56kbit modem kit was available for a moderate price. They weren't too difficult to put together. Alignment did take a scope, but took only a few minutes. About five people in San Diego had them. As far as I know, only three ever made it onto the air here.
I remember that modem, but also I remember that there were quite some issues at that time. It was not easy to reliably make 56k HDLC using affordable hardware at that time. For interrupt-per-character serial devices the performance of a PC-XT was not quite enough. There were DMA-based controllers but they were difficult to obtain, hard to find reliable drivers for, and expensive.
Some people built 68000-based boards for that kind of datarate, and later for 1-2Mbps, also using DMA. I also considered using PC-LANA adapters that had all the data generating hw as a co-processor but were not AX.25 compatible. (they use the NETBIOS interface, I added IP over NETBIOS to my version of NET to be able to use them) However, no real radio link has ever been made here.
Of course wide acceptation would have been even more difficult.
Today, the computer performance problem no longer exists, but the problem of wide deployment of a locally designed solution still exists.
Rob
On 2017-09-02 09:32 AM, Rob Janssen wrote:
A couple of decades ago, the "GRAPES" WA4DSY 56kbit modem kit was available for a moderate price. They weren't too difficult to put together. Alignment did take a scope, but took only a few minutes. About five people in San Diego had them. As far as I know, only three ever made it onto the air here.
I remember that modem, but also I remember that there were quite some issues at that time. It was not easy to reliably make 56k HDLC using affordable hardware at that time. For interrupt-per-character serial devices the performance of a PC-XT was not quite enough. There were DMA-based controllers but they were difficult to obtain, hard to find reliable drivers for, and expensive.
We used the PI2 card here at UBC, using the original pi driver and then the dmascc driver once it was available. It was a bit of a fiddle to find a clear IRQ/DMA on crowded machines but dedicated router boxes (an old XT worked) were pretty stable. Losing ISA slots on newer computers meant that we were limited to older systems.
With two local mountain top repeaters on UHF (using custom duplexors) we had a handful of users over 70-80 km paths ... kept my dad online for several years before cables modems made it to the farm :)
Eventually the remaining users lost interest and I gave up after the last repeater went down. At $800-1000 for a working system it just didn't get enough people to sustain itself, and cheaper broadband meant many of the original users didn't find it worthwhile.
Still have two repeaters worth of gear cluttering up my storage, hard to let go of a project that took so much of my time !
... Niall
On Sat, Sep 02, 2017 at 10:00:19AM -0700, Niall Parker wrote:
Still have two repeaters worth of gear cluttering up my storage, hard to let go of a project that took so much of my time ! ... Niall
Yes, I have a pile of old electronics stuff in my garage too. I realized the other day that it will cost more to have the junk man haul it away than it's worth, so until I need the space for something else, there it sits. I have a box of TAPR TNCs, for example. They all need new batteries by now. Nobody wants them. And the old Motorola repeater gear is HEAVY. It's getting painful to lift. It doesn't sell on Ebay.
It's just that I worked so hard in obtaining these things in the first place that it's hard to let go. - Brian
On 3/09/2017 8:49 AM, vk2tv wrote:
It's just that I worked so hard in obtaining these things in the first place that it's hard to let go. - Brian
_
Isn't that a familiar line?
Yeah, know that feeling. I've got a shed full of old junk that's probably now better suited to the e-waste recyclers. :)
On Sun 3 Sep 2017, Tony Langdon vk3jed@vkradio.com wrote:
On 3/09/2017 8:49 AM, vk2tv wrote: Brian Kantor wrote:
It's just that I worked so hard in obtaining these things in the first place that it's hard to let go. ????- Brian
Isn't that a familiar line?
Yeah, know that feeling. I've got a shed full of old junk that's probably now better suited to the e-waste recyclers.
Tony,
By any chance, do you know the names, model numbers, and capabilities of the items in your shed off the top of your head? I'm just curious: I'm thinking of starting an old junk museum and I'll need donations. ;-)
73,
Bill, W4EWH
The theme song to Sanford and son is rolling through my head from that last comment.
Best,
Elias
Sent from my iPhone
On Sep 3, 2017, at 10:07 PM, Bill Horne bill@horne.net wrote:
On Sun 3 Sep 2017, Tony Langdon vk3jed@vkradio.com wrote:
On 3/09/2017 8:49 AM, vk2tv wrote: Brian Kantor wrote:
It's just that I worked so hard in obtaining these things in the first place that it's hard to let go. ????- Brian
Isn't that a familiar line?
Yeah, know that feeling. I've got a shed full of old junk that's probably now better suited to the e-waste recyclers.
Tony,
By any chance, do you know the names, model numbers, and capabilities of the items in your shed off the top of your head? I'm just curious: I'm thinking of starting an old junk museum and I'll need donations. ;-)
73,
Bill, W4EWH _________________________________________ 44Net mailing list 44Net@hamradio.ucsd.edu http://hamradio.ucsd.edu/mailman/listinfo/44net
On 4/09/2017 1:07 PM, Bill Horne wrote:
Tony,
By any chance, do you know the names, model numbers, and capabilities of the items in your shed off the top of your head? I'm just curious: I'm thinking of starting an old junk museum and I'll need donations. ;-)
Unfortunately no, such organisation is not my strong point.
-
Bill Horne -
Brian Kantor -
Elias Basse -
Kathie Dart -
Niall Parker -
Rob Janssen -
Tony Langdon -
vk2tv