[Motorola] CDM-1550 Band Expansion?

[Eric Lemmon]

Jay,

No, that's not feasible- IMHO.  Each of the three splits averages about
16% spread, which just about pushes the bandwidth envelope as far as
manufacturing tolerances will allow.  For comparison, note that a
high-VHF radio that tunes 150-174 MHz has a spread of about 14%.

If you refer to the CDM Detailed Service Manual 6881091C63, you'll see
that there are significant differences in components among the three
splits.  Given that the main circuit board is machine-assembled with
microscopic surface-mount devices, I would not try to re-manufacture the
board to a different split.  Even if you had the skills, patience,
budget, and equipment to perform the modifications, you would then find
that the firmware has an embedded code that identifies the original
bandsplit, so CPS would not allow you to program out of that bandsplit. 
A hacked radio that doesn't work has little value in the marketplace.

I think you would find it cheaper in the long run to sell your CDM1550
and buy a new or used one that is made for your desired band.  The
possibility of creating a paperweight is very great.  I may be overly
pessimistic, but that's my gut feeling.

73, Eric Lemmon WB6FLY

"Coote, Jay" wrote:
> 
> The Motorola CDM family of lowband radios have the following splits:
> 29.7-36 MHz
> 36-42 MHz
> 42-50 MHz
> 
> My questions is can the band splits be opened up a little?