Okay, that sounds familiar, John. It had pots that may have been belt driven that increased or decreased the resistance depending on rotation.
Something else I remember - the person put a plastic garbage can over it to keep out the rain. I know why he did that. I just find it amusing that I remember that detail.
Let me ask one other question before I get to comments. I actually have one U-100 and one U-110. Is this going to be an issue? I'm not sure what the difference is.
@AA5AM: Don't put too much into it. I thought someone might remember it off the top of their head. There are several solutions that I got that may be better than what I was looking for.
@KL7XJ: I vaguely remember the SatEL being advertised in the Journal. I think it is time to renew my AMSAT membership and maybe purchase those DVD's.
@VK4HHH: I have looked at K8DAV's setup quite a bit. I got myself confused thinking it only worked over a parallel port (that is an issue but can be overcome unless portable/field). However, I realized the basic stamp controller worked over a serial port (not an issue). I may go this route, but I'm still looking for options. Will this setup work using SatPC32 which was my preferred tracking software when I was satellite active?
@KO6TH: I like your approach. Let me see if I got my head wrapped around your design - serial interface to the FODtrack board which then controlled your controller? That's pretty cool.
@VU2POP: Very nice homebrew tower and rotor setup.
Still working out my options. I just want something simple that I can take to the field using a modern laptop.
Lot's of good suggestions here.
Downloaded the form to renew my AMSAT membership too.
73, Joel - W4JBB
On 7/3/2012 5:09 AM, John / NS1Z wrote:
I think you are referring to the satellite compendium put out many years ago. Ii am sure it is out of print now. Over the years I built a couple and one even auto track (but a LOT of work)
-----Original Message----- From: Joel Black Sent: Monday, July 02, 2012 6:09 PM To: AMSAT Subject: [amsat-bb] U-110 Rotor Setup
I am looking for an old article regarding the use of two U-110 rotors for satellite operations.
I have gone through all my old references and cannot find what I'm looking for.
Basically, it was a setup using two U-110's (or it could have been two U-100's). The homemade controller used either toggle or rocker switches and had a digital readout of AZ/EL using DVOM's. As far as I remember, it was all manual. I remember seeing this in the back of some publication, but I cannot find it.
Does anyone have any inkling of and idea what I'm talking about?
73, Joel - W4JBB _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Joel Black wrote:
@KO6TH: I like your approach. Let me see if I got my head wrapped around your design - serial interface to the FODtrack board which then controlled your controller? That's pretty cool.
Hi Joel,
Well, sort of. FODTrack has two different Az/EL rotor interfaces which you can choose from. One uses a parallel port, and talks to a bit of custom analog hardware to directly sense the rotor position and turn on/off the motors. The other uses the serial port, and was intended to be used with the Yaesu controller of the day. What I did was to build my own controller that emulated enough of the Yaesu serial protocol for the FODTrack software to talk to it via the serial port. So, I wasn't using the analog FODTrack controller board hardware at all.
A fundamental decision that needs to be made early on is what type of feedback your rotors give. There are two kinds - analog (potentiometer), and digital (index switch). The analog type can be controlled much more precisely, but the interface is more complicated. The digital types (which are what I have), have a resolution of around 5-10 degrees. Fortunately, 10 degrees is plenty accurate for most uses, so I went with what I had. Others have added Pots to their digital rotors, and I suppose one could add an index switch to an otherwise analog rotor too. Just decide which way you want to go up front, then work out the rest from there.
By the way, I've long ago retired the FODTrack software, and now use Predict on my Linux box. I had to tweak the code a little (yea Open Source!), to output the same Yaesu commands as what FODTrack spit out. Alternatively I could have modified the controller. Either way, it's still working great.
Good luck,
Greg KO6TH
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Joel Black