Description
AVL 1200K1210K – RCI SNG Antenna System is a used antenna package removed from a news truck a few weeks ago, in order to make way for a larger mobile antenna.
Here are a few photographs of the antenna as mounted on the last owners SNG truck – no we don’t have the truck.
We have tested it and made some minor improvements and now it is ready to ship
TECHNICAL DESCRIPTION
The 1.2M SNG Antenna System is an elevation over azimuth positioner featuring the simple,
rugged Roto-Lok® drive system which produces very low backlash, high-stiffness and high reliability and driven by a low backlash, gear box with DC motors. All drive components are high strength steel, housed in lubricated-for-life housings which results in the most reliable, no
maintenance system with the minimum of weight.
The reflector is an offset, prime focus, carbon fiber reflector illuminated by a corrugated feed horn. The RF power amplifier may be installed on the feed boom, positioner backing structure or inside the truck. Handcranks across az and el axis are included allowing easy antenna positioning if the controller malfunctions. The basic 2-port antenna system weighs only 117 pounds.
RF SYSTEM
The offset reflector/feed system produces co-polarization patterns that easily meet the 29-25 log
theta requirement. The .8 f/d optics reduces off-axis cross-pol in the asymmetrical plane. The RF
power amplifier may be installed on the feed boom, positioner backing structure or inside the truck.
Waveguide run to power amp across each axis can be via twist-flex or rotary joints. The system
can be configured for either 2-port or 4-port.
ROTO-LOK® DRIVE SYSTEM
The patented Roto-Lok® drive system utilizes highly-reliable aircraft control cables in a redundant configuration to achieve a zero-backlash, light-weight, very stiff drive system. It achieves this high tech performance using low-tech components by simply wrapping the cable around the driver capstan several times before wrapping the larger drive drum. The method used to wrap the capstan results a minimum free-length of cable.
The load in the cable on the main drum is exponentially reduced as it is wrapped around the drum. Therefore the total elongation of the cable when under load is minimized. The Roto-Lok® system results in stiffness of up to 10 times that of comparable gear or harmonic drive systems. The cables are pre-tensioned and spring loaded at the main drum attachment point, which eliminates backlash at installation and from any unexpected cable stretch in the future.
