Hi Folks!
Has anyone developed a modem that can be integrated with an existing 222 or even 219 MHz radio such as an unmodified or modified Alinco DR-235? I'm looking for something faster than a 19.2 kbps packet modem.
Even if filters need to be hacked and the radio modified, that would be worth the effort to get the propagation characteristics.
The bandwidth needs to be within the regulations, but we could request an STA if needed. There are NO 222 MHz repeaters within 50 miles of here, so I think we can "wedge in" a moderately broadband digital link in the band.
The idea would be to bridge "mesh islands" with a slower, but reliable link.
Alternatives using other RF decks including the TYT TH-9000 or data modems from other services in the 216-230 MHz range are welcome!
We simply want to push IP packets across a network. It is likely that we would take an IP tunnel connection to make this work, but other approaches are welcome!
Thoughts anyone?
73,
Gordon Beattie, W2TTT
201.314.6964
W2TTT@ATT.NET
Gordon.BeattieJr@VIAVISolutions.com
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Sure not the case here. There are zero unassigned 220 repeater pairs here in southern California - with many channels having multiple repeaters.
"The idea would be to bridge "mesh islands" with a slower, but reliable link. "
Hi, Gordon:
I do not think that a 19k2 link would keep up with the OLSR traffic between 2 AREDN network islands.
I did this test:
Our local network has OLSR Entries: Total=244, Nodes=65
I installed 'iftop' on a 'terminal' node.
The 'terminal' node does no (between nodes) network routing...only OLSR and services.
'iftop' reported an average though-put of ~13kbps with its neighbor DtD node.
I do not think that you will get 13kbps through a 19.6 kbps raw data rate link.
What services were you considering transporting between AREDN islands with this 19.6 kbps link?
Regards, Chuck
Orv W6BI
Note for USA:
Due to CFR 47 Part 97 FCC regulations, for the 70cm amateur radio band (restriction to 100kHz and 56kBaud),
only the setting "modulation 20" of NPR-70 seems to be legal in USA.
Please always check your local amateur-radio regulation before buying and using NPR70.
Modulation 20: Symbol Rate 50kS/s, bandwidth 100kHz, raw datarate 100kb/s raw, usable datarate 65kb/s.
Likely services that could be transported across a 65kbps link is MeshChat, email, Winlink, BPQ-BBS,...
I doubt that a single audio channel could be transported due to AREDN/OLSR overhead.
73, Chuck