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  Spectra Hacks
and Bit-Banging

By James S. Vooght K2JSV
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Model Number

Serial Number


First things first: Anyone attempting these modifications should be aware of the fact that you could render your radio inoperable with one wrong keystroke. This guide may seem a little too simplified for the experienced bit bangers, but it's for the ones that want to break into the world of new and exciting Spectra Features.

With that out of the way, on with the fun. This was done in Lab Version 6.00.05 but the screens are similar on older versions of the software. The location of the BitBanger from the main menu is in the Alignment/Service Menu. When entering this menu you will need your radio powered up and connected to the computer with the RIB and cables. It will read the radio quickly every time you move up or down a menu item in this section. Not to worry; this is normal.

This is where you should be now

In this Service Menu there will be several areas for alignments and board replacements. You will want the F8 option for "Service Aids and Trouble Shooting Aids".

The Service Aids Menu, Notice the "Bit Banger" option

From the Service Aids Menu you’ll need to select the F4 option for the "BIT BANGER". You are now entering the area where you should tread lightly; a wrong move can spell certain death. If that doesn’t scare you... The rest is simple.

The Bit Banger Utility

The screen you should now see is like the one above. You’ll have 2 fields, one for the data location and one for the 2 digit data at that location. All the locations and data are in Hex format (0-9, A-F). In these fields you can scroll with the up and down arrows or type in the data or location and hit Enter. Below is a chart of the various entries and data locations you will need for changing your model number, your control head type, Bandsplit and Serial number.

Any time you go to a data location and change the data in that location you must program the change. If you scroll to the next location without hitting F8 to program it, you will lose the change you made.

So. You have now made your data location changes that you want for various things like Your Control Head, Serial and Model Numbers, etc. You exit out of the service menu and your radio reboots to show a FL 01/82. "EEK!! I killed my radio." Fear not. That fail code is for a Checksum Error. This error has a very very simple fix. Exit out of your Labware and boot up your normal Spectra RSS. Read your radio (F2) with the normal Spectra RSS and then immediately Write your radio (F8) WITHOUT making any changes. This will clear up any Checksum Errors within the radio. Once it finishes the writing and rebooting cycle you will see that the FL 01/82 is no longer there. Since you are in the normal Spectra RSS go ahead and make any other standard codeplug changes you may need to after whatever changes you made with Lab. (i.e.: Control head names if you went to or from a Sys9000 CH, Editing button functions, whatever.)

Bit Locations and Options

All data locations are labeled with "Radio meaning =(equals) Bitbanger Data". For Example D = 44, Data bit 44 in the bit banger would show up as "D" in the model number.


Model Number Locations

Sample Model # D 4 4 K X A 7 J A 7 B K
MLM Location 6048 6049 604A 604B 604C 604D 604E 604F 6050 6051 6052 6053
Command Location B675 B676 B677 B678 B679 B67A B67B B67C B67D B67E B67F B680
Data Options D = 44 1 = 31 1 = 31 F = 46 G = 47 A = 41 5 = 35 J = 4A A = 41 2 = 32 A = 41 K = 4B
Data Options L = 4C 2 = 32 2 = 32 K = 4B M = 4D   7 = 37   B = 42 3 = 33 B = 42  
Data Options T = 54 3 = 33 3 = 33 V = 56 X = 58       C = 43 4 = 34 E = 45  
Data Options M = 4D 4 = 34 4 = 34           D = 44 5 = 35    
Data Options   5 = 35 5 = 35           E = 45 6 = 36    
Data Options   6 = 36 6 = 36             7 = 37    
Data Options   7 = 37 7 = 37             8 = 38    
Data Options   8 = 38 8 = 38             9 = 39    


Control Head Type Serial Number Locations

Bit Location = 605F

61 = 136-162 MHz
62 = 146-174 MHz
63 = 403-433 MHz
64 = 438-470 MHz
65 = 450-482 MHz
66 = 800 MHz Range
67 = 900 MHz Range
68 = 482-512 MHz
Bit Location = 6060
A4 = BF
A5 = AF
A7 = ED
A9 = CD
Command Board




If you want to change your serial number, it may be best to use the serial Number Utility (F7) in the Service Aids Menu. This will prevent mistakes and a FAIL 999 on the display.

A note about the Bandsplit (location 605F). All of the values in the table above will result in 5 kHz deviation and modulation acceptance. The 900 MHz radios typically run 2.5 kHz deviation and modulation acceptance. Stock radios have "E7" as their range value. It seems that the most significant bit (hex 80) when ON sets the radio for 2.5 kHz operation, and when OFF sets the radio for 5 kHz operation. This has been verified on multiple radios and multiple bands (VHF, UHF, and 900 MHz). When the bandsplit value was changed from "62" to "E2" on a VHF radio, the transmit deviation was reduced from 4.7 kHz to 2.35 kHz. Similarly, the recovered audio (at one particular volume control setting) increased from 426 mV to 852 mV. Likewise, when the bandsplit value was changed from "E7" to "67" on a 900 MHz radio, the transmit deviation increased from 2.7 kHz to 5.4 kHz and the recovered audio decreased from 520 mV to 260 mV. The squelch also opened under this condition, because there wasn't enough high-frequency noise amplitude coming into the squelch circuit as compared to the narrow-band operation. Thanks go to Alex K6LPG for bringing this to our attention.

Note that this narrow/wide selection only affects the audio levels. The modulation acceptance of the receiver is dictated by the crystal filters on the RF board and that cannot be changed through software or hex-editing. But for those areas that have 5 kHz repeaters on 900 MHz, this is an easy way to make the radio work a bit better for those users that need it.

As with all hex-editing sessions, after changing any data bytes, the radio reboots with the dreaded "FL 01/82" error and you need to recover from that by reading the radio's code plug then immediately writing it back to the radio.

The author can be contacted at: VooghtJS [ at ] k2jsv [ dot ] com.

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This page first posted on r-b 10-Sep-08.

Article text, layout, and graphics Copyright © 2008 By James S. Vooght K2JSV.
Screen shots and conversion to Repeater-Builder format by Robert W. Meister WA1MIK.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.