MCS2000 remote head kit question- theoretical length limit

[k7kcn]

I have a situation where I have been asked to install a MCS2000 VHF mobile in a railroad passenger car. The folks would like the control head and speaker at the rear end of the 85 foot long car but have the rest mounted in an electrical cabinet up front at the other end.

I have two issues I am trying to work with.

1. The end of the car is cramped with a small lockable cabinet already there that is built into the exterior wall that would be able to house the control head and mic, but not the rest of the radio. The speaker would be mounted to the wall nearby but doesn't need to be secured.
2. Running the coax out from the end of the car is not the best as there is no access to the underside of the roof where the external antenna would be mounted. In the front of the car where the electrical cabinet is has open access to the roof.

I see there are 18 wires in the head and two for the speaker that would be needed to be extended. Does anyone have an educated guess on if this length would allow the head/radio function correctly? I would understand that if done the cabling would more likely be a larger AWG for less loss which I have no issue with.

Any comments or suggestions would be more than greatly appreciated, thanks.

-Kevin

[k7kcn]

Replace 'exterior' with 'interior'.

[madfrenchie]

From my experience with working on the MCS2000 this should be possible. I have extended the cable to lengths of about 50 feet, never as far as 85.

A few things you want to keep in mind is like you mentioned, make sure you have good solid wiring, and SOLDER EVERYTHING neatly. A poor solder joint can cause a headache, also use Shrink Wrap on each individual wire as well as the full wire once complete. With that much vibration riding along the tracks you don't want your connections to become loose or damaged.

In the end, I believe you shouldn't have any problem extending the cable that length.

[k7kcn]

Thank you for the info. Did per chance you use the same gauge wire for your 50' extension? If so and it still worked, if I can get my hands on slightly larger wire as what's in the remote cable now, my thoughts are if 50 worked I am comfortable in pushing it to 85.

Solder connections? You bet. Shrink wrap each and whole? Absolutely! Thanks for the reminders.

Will update here on the results when the project is complete.

-K

[thebigphish]

Don't the MCS2000 use serial data txfer to communicate between radio head and chassis? The longer the wire, the lower the reliable data txfer speed will be, due to interference and capacitance issues, so if the head uses 9600baud to communicate with the chassis, the normally accepted cable limit is 15m. I've never put pins 5 & 6 on my oscilloscope, but they are CLK & SPI, so wether or not it is a true RS232 - i simply cannot say, but if it smells like serial, you will have serial length issues to deal with

I'd say give it a try...

...oh that, and shielding, shielding, shielding!