Out of Band

From W3AXL Wiki
Jump to: navigation, search

Many commercial radios were not designed to operate in the amateur radio bands. However, many of these radios will tune to and perform well on almost all the frequencies allocated for amateur use (within their designated bands, obviously). Most radios will operate with nothing more than a software modification to allow for programming out of band frequencies, some radios include the amateur bands in their frequency range, and a select few radios will require hardware modifications to allow them to tune to the frequencies in the amateur spectrum.

Out of Band Radio Support

Motorola Radios

Jedi Series
HT1000 Fully working, shift-key method
JT1000 Unknown
MT2000 Fully working, hex-edit method
MTS2000 Fully working, hex-edit method
MCS2000 Fully working, hex-edit method
Astro Series
Astro Saber Fully working, hex-edit method
XTS3000 Fully working, hex-edit method
Astro Spectra Fully working, hex-edit method with hardware mod
APX Series
APX radios are firmware locked to in-band only
TRBO Series
Uses alternative hex-edit method

Methods

Shift-key Method

For early DOS-based software such as the Maxtrac and Visar RSS packages, entering out of band frequencies is as simple as holding down the shift key while entering your desired frequency. At first this will appear as though you are typing jibberish into the frequency field, but it will automatically change to the entered frequency when you exit the field. Note that you must fill out the entire field while holding the shift key, including adding extra zeros as necessary until you run out of space. Some RSS packages will give a warning about out of band performance, but for the most part you can ignore this.

A partial listing of known RSS packages that support the shift-key method is shown below.

  • HT1000/VISAR RSS
  • Radius/Maxtrac RSS

Hex-edit Method

For some DOS RSS packages, and for almost all newer Windows CPS packages, the band limits for radios are stored in hex within the executable file itself. Because of this, changing the band limits to allow for amateur frequencies can be slightly more difficult. The use of a hex editor such as HexWorkshop or HxD is required, but the process itself is fairly straightforward.

The Akardam website has a very in-depth and helpful article on changing the band limits for Motorola CPS packages, diving deep into the theory behind the mod. The short version of what you need to do is spelled out below.

For most CPS packages, the bandsplit numbers are stored as intel unsigned long hex strings. The band edges are stored in units of hertz, so for instance an upper band edge of 470MHz would be stored as 470000000 Hz, and in intel unsigned long format this would be 80A1031C. Let's say you wanted to increase the upper limit to 480 MHz, or 480000000 Hz. In hex, this is 00389C1C. To perform the switch, open up the executable and run a search and replace function to replace every occurance of 80A1031C with 00389C1C. That's it. Now your CPS package will accept frequencies up to 480 MHz on a 403-470 radio.

Common bandsplit edges and their intel unsigned long equivalents are listed below:

Frequency (Hz) Hex
144000000 00449508
146000000 80C8B308
440000000 00DE391A
450000000 8074D21A

For 900MHz out-of-band info, W9CR has a great resource here