[amsat-bb] Fw: Foxdelta ST-2 / LVB Tracker

Matty Cunningham manxmat at hotmail.com
Mon Mar 4 09:19:53 PST 2013

Hi Kyle,

I have an ST2 myself and use an old Cornell Doublier for azimuth, and an Alliance type U100 for elevation.

I put the control interface with a seperate PSU into a 2U cabinet that was used for other equipment, along with the transformers/phasing capacitors for each rotator - I used relays for switching the motors/directions with some diodes to stop reverse spikes from the relays getting back to the interface transistors.

I had no problems at all using this with a small dual band 2m/70cm yagi from Sandpiper, last year I upgraded my antennas and found a few issues with the controller not wanting to play.

I found if I disconnected my radio from the antennas, I had control of the rotators - re-installed the original antenna, and finding everything working again, I worked out I had some sort of earth loop weirdness going on.

My Sandpiper dual bander has a dipole feed for each band, isolated from the antenna boom, the new larger yagis for each band both have a gamma match, and grounded booms - this was what caused my issue with my controller.

Switching from an aluminium pole, to fiberglass for the elevation boom fixed  my problem - not sure if this would possibly help with your scenario, it may be worth looking at.

I would also check to make sure you have run through the calibration procedure for the interface.

I've successfully used the tracker with various bits of software (HRD rotator software, SDR V.1 console and others).

If I was to buy another, I would go for Howards LVB version from Amsat.

Good luck with getting it up and running.



Date: Sat, 2 Mar 2013 12:19:01 -0600
From: "K&R Yoksh" <yokshs at gmail.com>
To: <amsat-bb at amsat.org>
Subject: [amsat-bb] Fw: Foxdelta ST-2 / LVB Tracker
Message-ID: <156EAB2B86C041DE8991016DDFEFDEE0 at main2>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
 Hello Howard,
 Thanks for the reply. I have posted on the FoxDelta email group, but 
 received a reply. I should mention that I don't think that the ST-2 is
 malfunctioning, nor do I think that your code has a problem. I just have a
 different type of rotator than the typical Yaesu. It would certainly make
 things easier if I did, but it would be quite an ordeal to change the
 rotator in my situation.
 I did not know the background of the Foxdelta vs. the LVB. I do understand
 that Amsat gets a donation with every LVB, and my intention was / is to
 donate again to Amsat when I can.
 I can certainly see where you're coming from re: the IP. I guess if nothing
 else, the ham satellite community as a whole benefits from your public
 domain IP, which helps generate more interest in satellites and satellite
 As far as the hardware and software goes, I'll look at the grounding, but I
 am thinking that the issue lies in the fact that CDE uses a 12 volt 
 POT.. I built a simple resistor voltage divider back when I first got my
 Kansas City Tracker, so that the KCT would see 0-5v instead. This approach
 gives the KCT (or LVB) the correct voltage range, but I believe it may 
 the resolution of the feedback system?
 I'll also try some ferrites on the leads from the CDE rotator box, in case
 transients are to blame.
 I'm certainly no programmer, but the software seems to stop the rotator
 immediately when the ADC sample value equals the target azimuth value. Once
 the antennas stop moving, the final location is different by 20 degrees or
 so.  Once the rotator stops moving, however, the software doesn't recheck 
 see if the rotator is actually where it needs to be.
 My idea was to either change the ADC sample rate, or perhaps add a pause
 after the rotator stops, and repeat the routine to "fine tune" position.
 This is why I have been trying to recompile your source.. I've already got
 PICs programmed with your 0.7 and 0.9 HEX files..
 73, many thanks.

More information about the AMSAT-BB mailing list