[NLRS] Elevation rotators for small stuff

[Dr. Gerald N. Johnson]

On 9/12/2013 7:44 AM, Ray Johnson wrote:
>
>
> Good point Paul !!
>
> When I am doing sun noise experiments on the larger dishes (3-6 foot), I
> use a homebrewed Dobsonian Telescope mount that I built for a lousy 4 "
> reflector scope.
>
> The Dobson design was created by the Sidewalk Astronomers in San
> Francisco as a cheap way to get decent stability using readily available
> materials and was originally patterened after military gun mounts..
>
> I especially like the part where you take an old Gilmer belt, flip it
> inside out and then tack it to the base to create a huge, cheap drive
> gear. Works Great !!

Many farm grain gravity boxes use a roller chain with ends welded to a 
bar to make a rack for operating sliding doors. A few radio astronomy 
mounts used a big roller chain welded to a semicircular steel plate for 
the elevation drive. Each used a stock 8 or 10 tooth sprocket as the 
drive pinion. Works for all sizes of roller chain from miniature to 
enormous. Saves much machining. Shoup (www.shoupparts.com) has imported 
and american made 80H for $8.73 a foot imported (10 foot roll) $12.89 a 
foot domestic (10 foot roll). Also 100H domestic for $25.27 a foot in 
the 10 foot roll. Then they have doubled 80H, you don't want to know the 
price. 80H is rated at a working load of 3400 pounds tension. Might be 
severe overkill for a 10 meter dish. www.mcmaster.com shows tension 
ratings and has a very wide selection of chains.

1/2" pitch 40 is rated at 437 pounds, while the narrower 41 is rated at 
314 pounds working load. Similar to the more common bicycle chain sizes.

73, Jerry, K0CQ
>
> rayj WB0EBG
>
>
>
> Paul Beckmann wrote:
>> Just two random thoughts from the peanut gallery:
>>
>> 1) The technology and designs involved in the pointing of higher-end
>> amateur telescopes is pretty accurate these days under computer
>> control and
>> may provide parts and ideas for projects like these.
>>
>> 2) I'm seriously considering building up a new turntable for my 10G rig
>> where the dish is an "afterthought" mechanically. It seems that the MN
>> plumber's design that mine was built around is a bit silly with the
>> heavier
>> "stuff" hanging off this arm rather than the transverter, amp, preamp and
>> feed all being on a baseplate on a turntable and the dish attached to
>> that
>> somewhere. For portable use, you could "snap-on, snap-off" a dish to a
>> mount on the turntable and have a on-the-road low wind profile.
>>
>> Like I said, just thoughts in the wind.
>>
>> 73
>> --Paul, wa0rse
>>
>> *
>>
>> Paul Beckmann*
>> *1882 South Ln*
>> *Mendota Heights, MN 55118-4328*
>> *wa0rse at gmail.com*
>> *612-414-0302 (cell, leave msg)*
>>
>>
>> On Wed, Sep 11, 2013 at 11:50 PM, Donn, WA2VOI <wa2voi at mninter.net>
>> wrote:
>>
>>> Those dishes are nice... but the 10GHz feed is VERY scarce; not quite as
>>> hard to find as hen's teeth (maybe snake's legs). I was fortunate enough
>>> to find someone who had the 10GHz version but wanted the 24GHz one so
>>> both
>>> our costs were postage.
>>>
>>> 73 Donn
>>> WA2VOI/0
>>>
>>> ----- Original Message ----- From: "Doug Reed" <n0nas at amsat.org>
>>> To: <tosca005 at umn.edu>
>>> Cc: <nlrs at mailman.qth.net>
>>> Sent: Thursday, September 12, 2013 4:34 AM
>>> Subject: Re: [NLRS] Elevation rotators for small stuff
>>>
>>>
>>>
>>>
>>>> If I was going to do it, I was thinking of those 2' dishes I handed
>>>> out, swap in a 10GHz feed and mount the transverter electronics in the
>>>> original box on the back of the dish.
>>>>
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