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Motorola CDM750 6 Meter Deviation

Posted: Fri Mar 16, 2018 11:13 am
by skyler440
I have a Motorola CDM750 I am attempting to get in the 6-meter ham band. The VCO locks to around 53.5MHz which is good enough for me to use for my main purpose at 52.525 simplex.

I am trying to get the deviation set right. The max deviation past 51MHz decreases from 5KHz at 50MHz to about 1.5-2KHz at 52.525. I have changed all of the tuning piers with the W9CR waris chirp script, so I can get the TX power stable across the band, but I am unable to find any setting in the tuner software for deviation.

Anybody have any experience with the CDM750 for ham bands, in particular 6-meter? Is it possible to modify in only software, or is a hardware modification required as well?


Thank you,
Skyler KD0WHB

Re: Motorola CDM750 6 Meter Deviation

Posted: Sun Mar 18, 2018 3:07 pm
by KitN1MCC
The CDM on lowband are known to burn out

Re: Motorola CDM750 6 Meter Deviation

Posted: Mon Mar 19, 2018 5:14 am
by skyler440
KitN1MCC wrote:The CDM on lowband are known to burn out
What does that have to do with deviation though?

Re: Motorola CDM750 6 Meter Deviation

Posted: Tue Mar 20, 2018 8:38 am
by AD0JA
I had this issue with a 6m lowband 1250 as well. Never could figure out how to fix it, I read the BSM and re-aligned everything in the tuner but no luck. Gave it back to its owner so too late now.

The GE MLS1 lowband works much better. I made an Excel spreadsheet to calculate hex values for it.

Re: Motorola CDM750 6 Meter Deviation

Posted: Tue Mar 20, 2018 3:16 pm
by KitN1MCC
Just giving info.