WB4HRO “Portable” D-STAR Repeater

September 27, 2010

D-STAR is a digital voice mode for amateur radio, and one of its neatest features is seamless VoIP. Obviously, this requires the repeater to have an Internet connection of some sort, which is easier said than done for many repeater sites. The repeater I manage, WB4HRO, has the luxury of living in an office with a fast DSL connection. Not all sites are as lucky as ours, however.

So what’s this about the repeater being “portable?” We also attend several trade shows throughout the year, and the repeater goes along with us to be set up. Most of these trade show sites do not have public wireless, and even if they did, it wouldn’t facilitate the intricacies of the D-STAR network, so we bring our own access in the form of a Sprint aircard.

When the thoughts to take the repeater on the road first came about, I was tasked with figuring things out. After trying out one of Cradlepoint’s routers only to discover it wouldn’t work as the direct endpoint, I began delving into the “forbidden” world of double NATs. I’ve used “double NAT” setups to share hotel Internet on several occasions, and it shined in this setup. The setup in the rack at present has a Soekris net4801 running m0n0wall with for the “internal” network and its external address set as The WRT54GL that hangs on the office wall has the ports forwarded to the Soekris’ address which then have the same forwards for the gateway server. When on the road, the WRT54GL is replaced by a machine set up with the same forwards, presently my Cradlepoint CTR350. It works incredibly well!

I used my preexisting knowledge of networks for this project, and the knowledge gained from this project helped push forward my own portable network projects.

Until next time!

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