Spring 2008 Issue

Communicating Voice, Video, and Data with Amateur Radio

Getting on the Internet
Your First HSMM Radio Station

By John Champa, K8OCL


The Linksys WMP54G Wire less-G PCI adapter.

In our previous column we discussed an HSMM radio repeater (Wireless Access Point/Router + PC) and the setup of a simple RAN (Radio Area Network). This time we will look at what is in a basic HSMM radio station (client). However, first let us look at another related area.

HSMM Radio Mobile I-Gate (Internet Gateway)

By combining an HSMM radio repeater with a laptop having broadband wireless Internet access such as provided by Sprint and other carriers, it is possible to provide shared Internet access for the radio stations connected to the RAN. Field experience with such a configuration indicates several special steps need to be taken for this configuration to work effectively:

1. Use a broadband card, or ED-VO card with an external antenna port.

2. Mount the broadband Internet access external antenna on the roof of your vehicle as far away from your HSMM radio antenna(s) as possible to avoid desensing.

3. Use two external antennas, if possible, on your HSMM repeater in order to achieve receive space diversity.

4. Mount the two HSMM antennas a minimum of 9–10 inches (approximately two wavelengths) apart; the more the better, up to about 10 wavelengths.

5. Inverter selection—determine the power requirements of the laptop and the HSMM repeater and any other devices, such as LED lights, etc.

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