Winter 2006 Issue

HSMM

The Hinternet on 5 GHz

By John Champa, K8OCL

What is the Hinternet? The word, actually an acronym, derives from what NASA loves to do so much—the linking of two or more acronyms. In this case, HSMM (high-speed digital multimedia ham radio) plus Internet equals Hinternet.

The Hinternet under development by many individuals and groups is intended to eventually become the ham radio digital WANs (wide area networks) formed by the linking of numerous local HSMM nodes or LANs. These HSMM nodes or LANs usually consist of inexpensive 802.11g access points (AP) operated under Part 97 rules in the 2.4-GHz amateur radio band, but could just as easily be an ICOM® D-Star network, or any other source of local HSMM amateur radio traffic.

Now to the 5-GHz Band
David Josephson, WA6NMF (wa6nmf@altaphon.com), suggests:

If people are looking for a flexible router solution and don’t want to learn Linux (or pay thousands for Cisco or Juniper gear) I can suggest Mikrotik. I have no connection with them except as a customer.

Mikrotik is a small company in Latvia (with local support in the U.S.) making a prebuilt Linux-based system that runs from flash ROM. No hard drive is needed. They also make inexpensive single-board computers with Ethernet and mini-PCI slots built in. Anything we would need to do in current 802.11-based amateur radio is covered in the Mikrotik code, including the ability (for $10 more) to operate the Atheros chipset-based radios (CM9 and NL5354 for instance) in the rest of the 5650–5925 MHz amateur band, not just the UNII/ISM segments. This greatly alleviates interference issues with WISPs (wireless internet service providers); amateurs have 100 MHz of spectrum not shared with any unlicensed service. You can download the manual, get further details, etc., at <http:// www.mikrotik.com>.

We are building some stations using this software and 802.11a cards. Mikrotik has a non-ack mode “Nstreme” that allows ranges over 40 miles, and a duplex mode “Nstreme 2” that uses two radios on different frequencies, one for transmit and one for receive. This allows separate transmit PA, if needed, and receive LNA. Together with surplus Telco microwave filters, duplexers, and antennas we are expecting 60+ miles with this, like we presently get with homemade T1 radios using FSK.

As a historical note, we have been operating T1 over 6-GHz FSK radios in northern California since the 1970s and as hams for the Office of Emergency Services since the 1980s. There is a truck on standby operated by Stephen Cembura, N6GVI. It contains a small PBX, phones, a T1 channel bank, and a steerable dish antenna on a hydraulic mast. This was used extensively during the 1989 earthquake and for several smaller events after that. This network predates WISP and VOIP by a “few” years.

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