SM120 Out of Band

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darkwood
Posts: 1
Joined: Sat May 11, 2002 6:39 am

SM120 Out of Band

Post by darkwood »

It has been a while since I have done any hex editing. I want to change the lower end freq and leave the higher alone, I have found my radio range in the mdf file and have edited there no problem. Now I have been trying all week to get the checksum back with no luck. Would someone please help me out to get this checksum back.

Thanks
Susan157
Posts: 962
Joined: Fri Apr 19, 2002 5:15 pm

Motorola SM120 out of band

Post by Susan157 »

:wink: I found the front end selectivity
to be poor when I went out of band.
I had a vhf .I had 140 mhz and 173 mhz in the radio and
it did not perform as good as other radios.
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Flatbush97
Posts: 87
Joined: Tue Sep 04, 2001 4:00 pm

Post by Flatbush97 »

What you need to do is take a checksum of the original file before it was hacked and right it down. Take a checksum of the new version as well. Do the math and figure out the differance between the two. Edit bits that are useless (such as the Motorola copyright text) in the file either up or down and keep on checksuming till you get where you need to be.
grenadiers
Posts: 33
Joined: Thu Jan 24, 2002 4:00 pm

Post by grenadiers »

I just completted a "out of band" mod on a friends SM120 VHF (150-170) and lowered it into the 140 range and he reports that it works just fine.

It was a PAIN trying to get the checksum to match back up again (it took about an hour worth of tinkering).

Give it another try, JUST REMEMBER to make a back-up of your MDF file BEFORE you do the mod, generate a Checksum (again BEFORE the mod), and after the mod generate another checksum... Then sit down and edit a usless area (copyright statement works) and save, genereate checksum, re-edit, generate, re-edit..... :cry:

If you haven't gone blind yet, (or insane) you should be able to get the checksum you require. You will come close several times, WRITE DOWN what you did and where, so you can go back.

GOOD LUCK!! :D
Grenadiers
Susan157
Posts: 962
Joined: Fri Apr 19, 2002 5:15 pm

SM120 Tested on service monitor?

Post by Susan157 »

:wink: When u did the upgrade did u put it
on the service monitor to see the change.This is a must
when u are doing a good job.
RADIOMAN2002
Posts: 1102
Joined: Thu Apr 04, 2002 4:00 pm
What radios do you own?: More than I can count

SM-120 out of band

Post by RADIOMAN2002 »

I found the easiest way to edit the MDF is merely swap the information of each bandsplit with each other. Swap the one you have with the one you want. No checksum required, because your not changing it.
Jim
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greywolf
Posts: 55
Joined: Fri Oct 12, 2001 4:00 pm

sm120 out of band

Post by greywolf »

Tried just swapping badsplits in mdf file and no go.......... :cry:
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oh2lak
Posts: 237
Joined: Sun Nov 25, 2001 4:00 pm

Radioman2002 check your PM

Post by oh2lak »

Radioman2002, please check your personal messages!

Erik
--
Erik Finskas OH2LAK
[email protected]
grenadiers
Posts: 33
Joined: Thu Jan 24, 2002 4:00 pm

Post by grenadiers »

Post from: Susan157

> "When u did the upgrade did u put it on the service monitor to > see the change.This is a must when u are doing a good job."

When I did the mod on a friends SM120 with ver.1 of the RSS, I only "lowered" the band split from 150-170 to 140-170. for the most part going down (or up) a total of 10Mhz should not cause any great problems. Any more of an increase you require running the radio through a few "tests" and have the RF range adjusted.

I also recomended to my friend to try to stay as close to the original 150Mhz range as possible. For the most part, he only needed to get into the 144.000Mhz range. And to date, all has worked fine and he is VERY happy.

It's a pain trying to come up with the correct checksum, but untill someone develops a version of "toolokit" for most (if not all) Motorola radios, well have to do it the old fashion way...
:cry:
Grenadiers
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