Narrowband/Wideband VHF frequencies, and Digital/Analog Radios Current and future Impacts to TNC’s fire programs Sam Lindblom, TNC Fire Initiative

The Issue Increased radio frequency usage (more users) Limited bandwidth available on the VHF spectrum Much more conflict between users Getting “walked” on… Potential increased regulation by the FCC

The Solution Convert to Narrow Band radio frequencies and equipment More on equipment later.... First, let’s look at the technology and the issue in more detail

What is Narrow Band? Narrow band frequencies use ½ the bandwidth of wide-band Normal wideband spacing is 25 Khz Narrowband spacing is 12.5 Khz For example, the TNCFIRE frequency is 151.625. Normally, the next frequency up would be 151.650. In narrow band, the next frequency is 151.6375 Narrow banding essentially doubles the number of available frequencies in the VHF “Business” spectrum (148-174 Mhz)

Sounds Great, right? PROS of Narrowband CONS of Narrowband Less traffic on currently “shared” frequencies Reduces the need to use tone/code guards CONS of Narrowband Operating wideband in a narrowband environment can cause problems Requires specific radio equipment Could be costly (more on that in a minute) It’s likely to be a long time before the general public will be forced to use narrowband and all wideband radios are obsolete

Why would I want to convert to Narrowband radios? If you regularly burn with federal partners, you will likely have to convert sooner than most If you experience significant radio traffic where you work, narrowband could help (but only if everyone converts) If you intend to participate on large wildland fire incidents of any kind

The FCC and Narrowbanding The Federal Communications Commission mandated that all federal agencies convert by 2005. This mandate was lifted until further notice… FCC does not currently have a time schedule in place to change the general licenses that we have now.

Equipment Some existing radios that we have can be programmed to narrowband (most likely so if they were purchased in the last few years) Bendix King EPH and GPH radios are OK At this point, you should avoid radios that will not work on narrowband frequencies Most radios require programming each individual frequency/channel as narrow or wide Narrowband radios alone don’t significantly increase costs

What about Digital? The problem with Analog and Narrowband frequencies Analog radios have a harder time sending and receiving narrowband frequencies, reducing their effective radiated power. Certain analog radios can lose up to ½ of their transmit distance.

What about Digital? Digital radios overcome this problem with a better capacity to process narrowband frequencies They don’t typically suffer from the same loss in effective radiated power as analog. Some digital radios using narrowband can theoretically transmit further than their analog counterparts using wideband Digital radios are expensive GPH Bendix King (Analog) is ~$500 DPH Bendix King (Digital) is ~$1200

Recommendations Continue to purchase analog radios unless you have a big budget Do not purchase radios that cannot process narrowband frequencies Know how to program your radios Know if you are working in a narrowband environment Ask all of your local cooperators Establish a communications plan if you contribute to local emergency response.