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Re: Lifetime of Azimuth/elevation setups in winter.



Jim,

You make reference to the Easy Track unit...it also appears in pictures in the 2005 ARRL Handbook.

Has this unit moved forward in recent days/months?  I have been aware of this project since its announcement years ago, but figured it was a "dead" project.  (I had offered to be on the beta test team with TAPR a few years back...)

Has it been rejuvenated?  

73,

Mark N8MH

At 06:37 PM 2/1/2005 -0500, Jim Sanford wrote:
>Patrick:
>I've had a full- blown, full auto az-el setup, in VA -- which is milder than where I am now (PA), but still, saw ice and snow.
>
>I never had weather issues.
>
>I did have design issues:  The Yaesu G5400 is GROSSLY underdesigned.  My first indication of this was when the elevation motor seized, taking out the power transformer, FOLLOWED by the fuse.  Later, I had ANOTHER elevation motor failure, despite ENSURING that there was no unbalanced torque.  This time damage was limited to the motor.
>
>Recommendations:
>1.  Make SURE that your entire array is balanced such that the elevation rotor is not trying to lift a bunch of weight, merely overcoming inertia (which is plenty if you have a 2m cross yagi).
>2.  Replace the fuse that comes with your rotor with the lowest value slow-blow which will not fail under starting load.  This is how I prevented further cascading failures.
>3.  If you run any kind of automatic control (recommended) make SURE that it has decent stall detection/protection.  If it issues a move command and doesn't see motion in some number of seconds, it should turn off all motors, inform you, and do nothing else until manually reset.  
>Not all products meet this test, I'm told.  Full disclosure:  My software was homebrew, and I'd implemented what I thought was rigorous stall detection, but obviously not.  Turns out that there were some subtlties with using multiple interrupts in DOS that I didn't initially understand, so insufficient testing did not disclose that my software was not doing all that I wanted.  After the first failure, I did some more rigorous testing and sorted it all out.
>4.  If you run automatic control under MS Windows, be careful.  I'm told that if Windows has an error (Critical stop??) which presents you a message you need to respond to (like an attempt to write to an empty floppy drive) EVERYTHING, including background tasks stops until you hit "OK".  (I've NOT tested this, and behavior may be improved with newer, more preemptive versions of the OS, but I'd verify before trusting.)  
>External devices, like Steve Bible's Easy Track may get commands from Windows tracking S/W, but do not care what windows does if they detect a stall -- they respond appropriately.  For this reason, I now prefer Easy Track to my homebrew hardware/software, except under DOS (which works just fine to track and work 9K6 baud birds.)
>
>Design notes:  The G5400 has no thermal protection for the elevation rotor, only limit switches at the extremes of elevation -- which are absolutely useless if a tree grows into the arc of your 2m longboom antenna..  The Azimuth motor DOES have a thermal trip inside it, tho it's held to the motor windings with a cheap piece of tape, which dries out and separates, leaving the sensor hanging in the air -- which I discovered when I had to repair the position sensor pot because the cheap tape failed, allowing the fine wire to the slider to break due to fatigue failure.  I repaired with good tape backed up by a UV ty-wrap.  
>This is why, despite trees, I never had to replace the Az motor.
>
>I'm TOLD (no first-hand experience) that the G5500 has no thermal overloads, only limit switches.  It appears to be a bit more rugged mechanically, so there's hope if you implement the recommendations above regarding stall protection and fusing.
>
>Again, I had NO problems, despite Ice storms and snow.  The above passed on for lessons learned/knowledge sharing.
>
>Hope this helps, happy to answer questions.
>
>Good luck and very 73,
>Jim
>wb4gcs@amsat.org
>
>
>Patrick Green wrote:
>
>>Hi All,
>>
>> I'm considering setting up a full blown satellite setup and am
>>concerned with the effects of WX on the fragile setups of AZ/EL rotor
>>setups.  I want to hear about people that have had horror stories and
>>ones that "set it up once" and never had issues with it for years. I'm in the Chicago area and we do freeze and get all the nasty winter
>>weather.
>>
>>I've always been a "portable" setup person and you might see me
>>operation the next HEO with something I can setup and tear down in an
>>instant.  I've always liked this because when I travel, I can access
>>the same quality setup where ever I go.
>>
>>73 de Pat --- KA9SCF
>>----
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>----
>Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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Mark L. Hammond  [N8MH]
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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