April 2017

April 2017


High Speed Multimedia is ARRL terminology. Quoting from the ARRL web site:

The Amateur Radio bands above 50 MHz can support computer-to-computer communications at speeds high enough to support multimedia applications.

Multimedia in this case refers to voice, data and image communications.

One approach that has been extensively explored is an adaptation of IEEE 802.11 technologies, particularly 802.11b operating in the 2400-2450 MHz band, known as the "Hinternet." Also under the HSMM umbrella has been an orthogonal frequency division multiplex (OFDM) system developed by John Stephenson, KD6OZH, and tested on the 6-m band.  

The Austin Broadband Hamnet (formerly HSMM-MESH) Special Interest Group have developed hardware and software changes to make use of inexpensive 802.11 wireless computer networking routers under Part-97 of the FCC rules. The terms Broadband Hamnet and HSMM-MESH are registered trademarks. The network operates on the amateur radio 13-cm band (channels 1 through 6). Major changes include extended range 10 – 15 miles with good Line-of-Sight. Privileges are also granted on the 9-cm-band (3 GHz) and the 5-cm band (5 GHz). Automatic address negotiation is employed so routers link automatically, with no user intervention within 5 seconds of coming into RF range of each other. They will also automatically link within 60 seconds from power up. If a BBHN (Broadband Hamnet) mobile node stays in range of the network, it will transition from node to node automatically. The same as a cell phone will transition from tower to tower. The software uses Optimum Link State Routing (OLSR) firmware. The RF section of the Linksys WRT54GL or Ubiquiti wireless router has been modified so only like modified routers can see each other. They are invisible to all other standard 802.11 routers. A word of caution about using the Linksys WRT54 series routers is that there is not enough memory to sustain another upgrade.   

What can be done with BBHN networking? The answer is anything that can be done on the Internet can be done with the BBHN. You can send email, surf the Internet if at least one router in the network is connected to the Internet. The BBHN network will allow the transfer/streaming of pictures, amateur digital video (ADV), or transferring files. BBHN can also be a source for a VOIP telephone network. During disasters BBHN can be used for shelter operations to provide written text to hospitals and pharmacies. It can also provide photographs of trees down, hail damage, power lines down or other infrastructure failure. It could be used to support first responder units in a disaster area. It could provide real time communications support for other responders in field such as ARES® (Amateur Radio Emergency Service®), and CERT (Citizen Emergency Response Team). Public Service Events could be supported such as Races/Runs/Marathons, Parades, Air Shows, Balloon Races. All of this is without the conventional Internet connection. 

Currently the BBHN groups in the Austin and Plano, TX areas have extensive networks up and operational for their tornado warning system for the NWS. Las Cruses, NM has around 30-35 nodes creating an umbrella over their city now. They have a VOIP telephone network setup and is running D-RATS (D-Star low speed data program).   

Why use the BBHN?  It is fast. The RF links are around 27- 54 Mbps. To keep everything in perspective we can compare BBHN to other daily amateur radio activities.

        Packet Radio/APRS 0.0012 Mbps

        Pactor III .003 Mbps

        D-Star DD 0.128 Mbps

Home Services

        Fiber optics 2 -15Mbps up link / 15-25 Mbps down link

        T1 1.5 Mbps

        DSL up to 1.5 Mbps up link/ 6 Mbps down link

        Dialup 0.014 – 0.056 Mbps   

We are presently using BBHN to provide the “Our Colors Run Together 5K Run/Walk” here in El Paso sponsored by the Rio Grande Cancer Foundation (RGCF). During the year, we will be presenting demonstrations in some local parks. Watch the calendar or event page on www.hamradioelpaso.com for location and time. We encourage those interested to come out and see what all can be done with this fantastic technology. For more information about BBHN go to http://broadband-hamnet.org.   

Questions and comments regarding the content of this article are welcome and encouraged. Send an email to the address shown below.

NOTE: The terms ARES® and Amateur Radio Emergency Service® is both registered trademarks of the American Radio Relay League, Inc. and are used by permission.

Lew Maxwell, KB5HPT
ARRL Emergency Coordinator – El Paso, County
Assist. DEC Culberson and Hudspeth Counties
Email: kb5hpt@arrl.net