Hi Cathy,
I have had a chance to look over the information about the packet network.
It is interesting to me in several ways, especially the chance to use a
Raspberry Pi in a new way. While my workbench is presently filled with
projects (and a couple of repairs) I will try to find the time and space to
participate if the project generates sufficient interest.
Do we have a date yet for visiting CVMC?
I tried to check into the RACES net with by back-up power system which
generated a lot of noise. As a consequence I am not sure that anyone
checked in since I could not hear them.
Alan
On Tue, Oct 1, 2019 at 1:26 PM Cathy James <catherine.james@xxxxxxx> wrote:
I am looking into the possibility of building out a small packet network
in Vermont, using VHF and UHF links between simple ham-owned home nodes for
real-time chat communications. No commercial sites, no fancy
infrastructure, just simple, inexpensive fun.
North Carolina has built a very successful network on this basis, using a
$35 Raspberry Pi as the node computer and $45 TNC Pis as the node
controllers. The key requirement is dedicated links between nodes on
different frequencies, which avoids the packet collision and persistence
problem. If you have three nodes A, B, and C, you would have a link from A
to B on one frequency, and a separate link from B to C on a different
frequency (probably on a different band; 6, 2, and 70 cm all work, and 10
is a possibility).
1200 baud may sound slow, until you realize that PSK31 was a very
successful chatting mode at *31 baud*. Packet seemed slow not because of
the 1200 baud limitation, but because of all the collisions and retries.
The dedicated links fix that problem.
Unlike Winlink and the old national packet network, we would NOT connect
this to the Internet. That would just swamp the packet network with
garbage it can't handle, much of which has nothing to do with ham radio.
More information here on the North Carolina team's great success with this
type of network:
http://tarpn.net/t/packet_radio_networking.html
Here's what you would need to build at each node:
http://tarpn.net/t/builder/builders_node_shopping_list.html
I've already had a phone chat with Tadd, the lead on the North Carolina
TARPN network. He's enthused about helping us get started.
Is anyone interested in working on this with me?
73,
Cathy N5WVR
