AT-600 Modification AT-600 Modifications Currently there several different versions of the ADI AT-600 firmware to hit the States. Which firmware version you have will affect how difficult expanding your rig's transmit range is. Prototype (firmware 1.00) and early production versions of the radio (firmware 1.10) were capable of accessing very wide expanded transmit merely through a software (i.e. keypad) modification. Using the keypad mod on middle versions of the radio (firmware version 1.20) extends the transmit range only very slightly. You must perform the hardware mod on the radio in order to access complete expanded transmit. The newest version, firmware 2.00, is now available!* It restores the ability to access out of band transmit from the keypad, and fixes a few of the radio's bugs, including the cross-band repeater problem that some of the older units suffered from. How do you know which version of the firmware you have? Try performing the keypad mod on the radio. After you enter the last step of the mod the display will read: KEY OK! Ver #.## Now, on to the mods! (NOTE: In the U.S. it is illegal to use this radio on any band for which it is not type accepted and on which you are not licensed. Perform these modifications at your own risk!) SOFTWARE MODS: STEP ONE: First enter the menu mode by pressing (F) and (0 SET / SB) at the same time. Enter the following sequence of numbers: 1, 4, 6, 2, and 3. Turn the radio off and then back on. STEP TWO: After performing the above modification continue with the following steps to expanded the radio further: Enter menu mode by pressing (F) and (0 SET / SB) at the same time. Enter the following sequence of numbers: 1, 4, 6, 2, 3, 1, 1, 2, 8, and 9. Turn the radio off and turn it back on. HARDWARE MODS: MOD #1: Open the radio and remove Q220 from the printed circuit board. Replace the radio cover. Turn the radio on by holding down (F), (LAMP), and (5), and pressing the (PWR) button. MOD #2: Open the radio and remove Q220 and Q221 from the printed circuit board. (You do not need to remove Q220 if you already removed it by performing Hardware Mod #1). Replace the radio cover. Turn the radio on by holding down (F), (LAMP), and (5), and pressing the (PWR) button. To find the location of Q220 and Q221 click here to see a diagram. You can also download 600mod.zip (209 KB), which contains several photos and diagrams showing the location of the components. WHAT THESE MODS DO -- Ver 1.00 and 1.10 SOFTWARE STEP ONE: This mod expands the receiver to cover 100-199.995, 330-499.995, 830-868, and 896-999.995 MHz. SOFTWARE STEP TWO: The transmitter will be opened up to cover 100-199.995 and 400-499.995 MHz. HARWARE MOD #1: The radio is expanded to transmit from 138-174 and from 430-470 MHz and receive from 130-174, 350-470, and 900-985 MHz. HARDWARE MOD #2: The radio will transmit from 100-199.995 and 400-499.995 and receive from 100-199.995, 330-499.995, 830-868, and 896-999.995 MHz. * WHAT THESE MODS DO -- Ver 1.20 SOFTWARE STEP ONE: This mod expands the receiver to cover 100-199.995, 330-499.995, and 896-999.995 MHz. SOFTWARE STEP TWO: The transmitter will be opened up to cover 142.5-149.5 MHz. The receive range and UHF transmit range remain unchanged. HARWARE MOD #1: The radio expands to transmit from 138-174 and from 430-470 MHz and receive from 130-174, 350-470, and 896-999.995 MHz. HARDWARE MOD #2: The radio will transmit from 100-199.995 and 400-499.995 and receive from 100-199.995, 330-499.995, and 896-999.995 MHz. WHAT THESE MODS DO -- Ver 2.00 Version 2.00 was released on November 3, 1997. * It was released instead of what was projected to be new version 1.30.* Version 2.00 is considered to be a major revision to the radio's firmware. SOFTWARE STEP ONE: This mod expands the receiver to cover 100-199.995, 330-499.995, and 850-868, and 896-999.995 MHz. SOFTWARE STEP TWO: The transmitter will be opened up to cover 100-174, and 420-470 MHz. HARWARE MOD #1: The radio expands to transmit from 138-174 and from 430-470 MHz and receive from 100-174, 350-470, 850-868, and 896-999.995 MHz. HARDWARE MOD #2: The radio will transmit from 100-199.995 and 400-499.995 and receive from 100-199.995, 330-499.995, 850-868, and 896-999.995 MHz. CELLULAR MODIFICATION: To my knowledge there is no way to modify the the U.S. version of the AT-600 for cellular receive. The AT-600 was designed to specifically not support receive on these frequencies, although the European version of the radio (AT-600D, for "Deluxe") does have this capability. A NOTE ABOUT THE RADIO SHACK HTX-204 and ADI HT-204: Yes, ADI also designed and manufactured the now no longer available HTX-204 for Radio Shack.* (Some of these radios have also been available as "ADI HT-204" radios.)* For all intents and purposes the radio is essentially the same as the AT-600. The two radios have nearly identical physical appearance, but they do have some slight differences in features: the AT-600 has more of them! For complete details on the differences check out AD7K's usenet posting! The Radio Shack HTX-204 can be expanded using the above modifications. For the exact frequencies it can be programmed to cover see Firmware Ver 1.10 above.