[TowerTalk] Using HDR-300 rotors on one control box

[Bryan Swadener]

Charlie,
I use a HDR300. IMO, the control function is not an issue. However, the indication function will be a problem. When diagnosing a design faux pas with the direction indication, I saw that the signal coming from the rotator could vary between rotators.
They use a 3-turn pot w/ 1:1 gearing from the rotator output shaft. But, the pot isn't installed to be at zero rotation = 0° azimuth, and the signal at 0° azimuth will be some value above 0 volts. Because no two pots are installed exactly the same, the output will be somewhat different from one rotator to another. Also, the voltage at 360° azimuth won't be the same from one rotator to another. Thus, the setup of the controller is going to be different -- the GAIN and ZERO (offset) settings will be different. Those controls adjust the input of the CA3162E A/D Converter such that its output is 0 to 360. I hope this makes sense.
BTW, something with my rotator's direction pot seems to have gone DOA recently, giving a steady "-87" indication. Substituting a trimmer made the display work. Ohmmeter tests in the shack indicate something not right on the tower. I ordered a replacement from Newark, Bourns pn 3547-1AA-102A (about $30 shipped).
vy 73,Bryan WA7PRC
 
     Date: Mon, 9 May 2016 17:35:46 +0000 (UTC)
From: n1rr at comcast.net
To: TowerTalk <towertalk at contesting.com>
Subject: [TowerTalk] Using HDR-300 rotors on one control box

Re: Using HDR-300 rotors on one control box 

Any issues I should know about before trying to control two HDR-300's separately 
(one at a time) with one control box ? 

-Charlie N1RR