Hex editing Maratrac RSS for 6m Conversion

[KA0XR]

I am trying to program a lowband Maratrac for use on 6 meters (46-54 MHz) but am having apparent issues hex editing the RSS. I have followed the recommendations on the Repeater Builder webpage for the lowband Maratrac series and made the specified edits (basically changing the four separate "F4 01" decimals to "1C 02" for the 6 meter conversion). However, even with these changes the modified RSS is still restricting me to the 42-50 MHz bandsplit.

Does anyone know if I'm missing something or if more edits are needed for this conversion than what is shown on Repeater Builder? I am able to read and program this radio's codeplug without any issues. BTW, I recently hex-edited the RSS for a Motorola P200 which allowed the radio to cover the entire 6 meter band, so I am not a total newbie to hex editing.

 

[N1GTL]

There is more to it than hex editing to get it right.

Scroll just below the half way point to see what we did to mine.

A Quick Look at a Motorola MaraTrac Mobile Radio

 

[petnrdx]

I know I replied to your message, but that reply disappeared.
The bandsplit hack I did was YEARS ago.
Might be easiest to just send you the file with the hacked limits.

 

[KA0XR]

I figured out what was wrong - I forgot to modify the file extension on the hex edited version of the RSS. The hex editing software I used automatically saved the edited file as just a "file". When I went into DOS I was inadvertently loading the original non-modified RSS that had an EXE extension, not realizing that I needed to change the extension manually on my hexed version.

Once I changed the extension to ".EXE" on the hexed version everything worked and I can now program up to 54 MHz. We also did the hardward mods that are described on repeater-builder. I do see in the RSS that I can still program down to 42 MHz, but I presume the sensitivity is probably not so great below 46 MHz following the hardware mods. There would be nothing to listen to locally down there anyway.

Thank you very much for the offer to send me a version of the hacked file, but we've got things figured out. Very cool to still have the well described step by step Maratrac mod instructions available to help give new life to these old wideband radios for 6m use! The radio we modified was retired from the Connecticut DOT 47 MHz system.

 

[petnrdx]

They are still a very good radio for six. Used one for a long time. Still have three or four on the shelf. I have the Syntor X-9000
which is a lot nicer since my memory is bad. But a 99 Ch Maratrac or even Maxtrac is still a pretty good radio.
We got 150 to 180 watts from the Matratrac's when we were running them. And they took it just fine.
With the 99 ch and MPL you can program pretty much every decent 6M repeater in the country.

 

[k9wkj]

if one might need the modded firmware mentioned on RB
one might ask
youll need a blanked eprom and burner of course
by using the Ham firmware you can avoid the wacked out power control troubles

 

[petnrdx]

If you were referring to my post about power out, we ran them at high power on purpose.
I never had troubles with the power control issues on the Maratrac, only the Maxtrac.
I do have both of the Ham firmware versions.
Max and Mara.

 

[k9wkj]

my response was more of a offer to folks that might need it
my Maratracs would get really squirrly when stretching out the band coverage
and my Maxtracs are much happier running the ham firmware

 

[petnrdx]

Yes, both the Maratrac and Maxtrac ham firmware are a great improvement.

 

[merlin]

If you are old hat with hex edit and know what fields to modify, you can do about anything the hardware permits.
Don't forget to correct the CRC.
I know hams have used SC4 files to shift bandspans, don't know programming with Maratrack and Maxtrac.
Might have to diddle with the PLL to get a stable lock.
Sadly I migrated to GE after the latest of Micor