Batboard

After a long and successful run using analog Motorola spectras on 900mhz and UHF in my vehicle, I decided to modernize to MCS2000s upon getting a new vehicle. Due to space constaints, I selected model-1 radios and picked up a couple that appear to be ~2002 vintage. Thus far, I have spent most of my time working with the 900mhz MCS2000. After programming and carefully aligning the radio, I was suprised to find that the sensitivity was 5 to 6 db worse than my trusty Spectra. Thinking there was a problem with the radio, I checked T/R diodes and the front-end pre-amp and everything seemed OK. I replaced those devices for good luck with no improvement.

Recently, I have tested several similar-vintage model-1 900mhz MCS2000s with the same result. I have a friend who has a ~1998 vintage model-3 900mhz MCS2000 and that one had considerably better sensitivity, analagous to my trusty Spectra. It appears from the service manual that all the RF design is the same between model-1,2,3 radios. I'm wondering if perhaps there was some type of design change between 1998 and 2002?

Anyone had similar observations or any idea on what I'm experiencing? I know Spectras pretty well but am just getting familiar with MCS2000s.

Thanks,
Randy/N3HFK

Last year a friend picked up a NOS 900 type 1 MCS made in 2003. I was the 1st person to program it since the initial freq's put in by the factory. It worked perfectly on 902/927 right out of the box. I'd suggest contacting Jim, N7MAQ, as he's real handy with these radios. Last year I purchased a type 3 from him that's just awesome. GARY

I have found significant RX sensitivity variability with my UHF MCS2000's and MTS2000's.

All the radios are "in spec" BUT the official spec is a poor 0.32uV for 12 dB SINAD (-117dBm) whereas my best UHF MCS2000 is around 0.18uV (-122dBm) and my worst is 0.32uV (-117dBm)....so there is a 5dB difference.

The variability with the UHF MTS2000 is even worse..I only have 1 really sensitive radio out of 6...but they are all "in spec".

The VHF MCS2000's and MTS2000's are much more consistent...all my VHF Jedi's have excellent sensitivity...very few radios will equal a VHF MCS2000 or MTS2000...sensitivity is better than 0.14uV (-124dBm).

It looks like it is the luck of the draw whether you get a good UHF or 900MHz MCS2000 or MTS2000!!!

I guess Motorola has such a pessimistic official spec so that deaf sets are still passed!!!

On later radios, Motorola now states a "typical" sensitvity figure of 0.22uV as well as an official spec of 0.32uV. However, I have found that the VHF CDM RX sensitivity is NOT consistent..some are hot..others are a bit deaf.