Ok, now for the bad news. There is no free ride with this single cable deal as I suspected. Their specs claim a loss of only 1db per device (2db total). Well, at certain frequencies that is true, but there are a few exceptions.
My measurements with a Spectrum Analyzer show a loss insertion loss depending on frequency. There are losses between 3 & 4db around the following frequencies; 493 (ch 17), 601 (ch 35-36), 675 (ch 47-48) & 710 MHz (ch 53-54).
This doesn't include the loss for each fitting in and out of the rotor & control box (probably around another 2 db total).
On the 1st attachment, two vertical divisions from the left is 470 MHz and one division from the right is 806 MHZ which is the current UHF TV spectrum. As you can see the trace is anything from flat. I did the test twice checking the 'null' of the scope with just the jumpers in line, then with both units connected.
BUT, there is a easy solution; Run a separate cable (or wire since you don't need to use another coaxial cable for a control signal) as you have done in the past and solder it to a 'F' fitting at either end and run your downlead as before. Done!
Ok, then what's the big deal? Repeated accuracy.
Any of the Channel Master clones imported from China are notoriously inaccuate especially if you 'rock' the rotor back and forth to 'tweak' the position of the antenna. No matter how many times you 'Zero' the rotor and control box out doing a full turn to 360 degrees and back to 0 degrees, it will never be accurate. Even with the solid state remote control box that Channel Master offers (9537), it doesn't help (much to my disappointment).
For the tests;
I ran the rotor in both directions. 52 seconds was the duration between 0 and 360 degrees. Unlike all other CM 'clones' this rotor will go to 450 degrees which means you don't have to go all the way around just to go from 10 degrees to 350 degrees. There is no 'north' stop.
I rocked the rotor back and forth a number of times and it stayed within spec which is 2 degrees of accuracy.
One thing I did notice was the readout of the control box was faster than the speed of the rotor. Doing a 0 to 360, the readout reached 360 long before the rotor did. It was repeatedly off by 45 degrees. IOW's the box said 360, but the rotor was only at 315. Same in going the other direction. When the box read 0, the rotor was at the 45 degree point.
Mind you, it didn't affect the final result. The rotor just keeps turning until it gets to where it should. I plan to contact the manufacture and inquire.
Current consumption was measured at .07 amps when in standby and .08A in the 'on' state. This is another device that is never 'off'. To me, even though it isn't much, to draw 5-6 watts when the device isn't doing anything is just poor design.
I measured .13 amp when the rotor was turning and under high stress (holding the rotor with both hands to try to stop it from turning) the load was.18 amp. The box does get slightly warm after a while, but it didn't seem excessive.
The 2nd attachment is the circuit board inside the rotor. Note on the right the solder joints for the F fittings.
The following are pics of the interior of the rotor with the bottom plate removed (above w/ the circuit board), the gear assembly, the housing without the main plate and the main shaft of this rotor showing the ball bearing race. There was no shortage of grease applied. Also note the two main bearings are brass.
added interior photos and clarified some text
Edited by videobruce - 2/12/13 at 4:43am