[PVRCNC] M2 RC2800PX rotor controller :: product pseudo-review

[Steve Jackson]

Oops, sorry:  M2 calls their Orion 2800 rotor a 'positioner' ... anyway ...

Some time back, the original model control box I had for my ten-year-old M2 rotor went awry.  It stopped reliably counting the pulses that indicate rotation, and eventually just lost its marbles.   I kept futzing with it until my patience wore out. 

M2 said "send it back and for $170 we'll rebuild it to the newest spec version, known to fix all the issues."

Either I could do that, or, buy a ~$600 Green Heron aftermarket control box and relegate the M2 box to the junque bin.  I picked the less-expensive option.

The rebuilt box, after round trip shipping, cost about $225.  For that, they sent what looks like a whole new box.  (I do think it IS new.)  It's MUCH more physically attractive than the old box.  The readout is in green LEDs, rather than red, and overall the whole thing is quite colorful.  Hookup was 100% exactly like before.  Superb.

Electrically, it's better in some ways.  It's far more adept at counting the positioner's pulses, and is quite accurate.  It also stops the rotation when it should.  The user interface is easier (improvement in this area is admittedly a low bar to reach) and several new features are welcome additions, such as the autocalibration mode, and the improved manual control modes.   The automatic speed ramp up and down functions work better than before, although I don't like to run the antenna anywhere near as fast as this thing can go.  It REALLY can whip the array around!  Ramp up and down don't really do anything when you always use the minimum speed like I do.  Of course, if I **do** want to go fast, a couple of clicks, and the antennas look like a helicopter.

The motor speed appears to be managed by a pulse-width-modulated control that's very effective.  Unfortunately, the PWN controller also has loads of spurious RF (plus harmonics) output that is not well filtered.  (Who designed this for ham station use?)  This noise is audible across 160, 80/75, and 60 meters.  Since the frequency dependent rolloff of this noise is fast enough after I added some quick clamp-on ferrites, the residual noise doesn't appear on any bands that have rotatable antennas here, so I guess it's not really a problem.  I could eliminate the remaining noise, if I so chose to spend the couple of hours to do so, using LC filters inside the box and my spectrum analyzer.  That's a project for when I have spare time. 

Interfacing with WriteLog and DX4WIN programs on the PC were both easy menu selections.  The box has one serial port on it, so if your new PC has only USB, you can use an adapter (which I did not try).  You can also operate this box from a command line terminal emulator, and many other ham software packages have direct support as well.

Color me happy.  This is a worthwhile upgrade for anyone who still has the old M2 orion controller.


73 Steve KZ1X/4
Chapel Hill




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