Dc Motor

I'm looking for a motor gearbox assembly to power a linear drive system over 270mm.

connected to the linear system will be to gas struts which in turn are connected to my antenna which weighs 8kg.

i'm having the motor/gearbox unit underneath and connecting the shafts of the gearbox and linear drive via cogs.

I need to unit to produce a decent amount of torque to move the linear slide but not at a high speed as the system will need to search.

Any suggestions????

I was looking for a surplus electric window motor but found this one: 46 RPM, 24 V DC @ 260 mA, 5/16 output shaft. Attach 11 in. 5/16 all-thread and carriage with brass nut. U shaped guide rails support carriage on ball-bearing wheels[4]. CAT # DCM-287, All Electronics. I made one several years ago , just different motor and length,no problams.