[amsat-bb] Source for 3" (76mm) pipe for dish mount?

[Zach Leffke]

onlinemetals.com

They sell small quantities without charging an arm and a leg.  A quick 
search showed 3" 6061-T6 schedule 40 aluminum pipe at 3ft length for 
around $50 with an additional $17ish for shipping to VA.

Like Alan mentioned though, Pipe "sizes" don't always match actual 
dimensions (3.5" outer diameter for the above mentioned 3" pipe).  They 
are pretty clear about that on the site though, showing the inner and 
outer tube diameters.  You could hunt around in their tubing and pipe 
sections under the metal of your choice (aluminum of various flavors, 
stainless, cold roll, etc) and probably find something that suits your 
needs without breaking the bank.


Also, dumpster diving.  Probably a full third of the Virginia Tech 
Ground Station metalwork was harvested from a metal dumpster outside a 
machine shop on campus (including some solid piping for our dish mounts 
and some of the counter weighting metals).  Just be safe about it, I got 
the OK from the machine shop folks and campus security folks to pull 
stuff out of the dumpster (some places take dumpsters like that in for a 
cash return at recycling centers and such, so taking what looks like 
'trash' is actually money out of their pocket).

Good Luck!

-Zach, KJ4QLP

Research Associate
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305

On 5/9/2016 5:25 PM, Daniel Cussen wrote:
> I would second the idea of getting a local welder or engineering shop
> to make up something suitable. If possible send it off for galvanising
> which they can do too.
>
> Note many of these larger dishes are not designed to use normal TV
> LNBs but are instead intended to use special manufacturer feeds, and
> they use unusual designs. Using the wrong feed will reduce the
> results.
>
> Here is information on the recommended installation in a fixed mount
> including concrete base.
>
> http://viasatelital.com/manuales/channel_master/channel-master-type-120.pdf
>
> If you are not using it in a fixed position, but for low earth orbit
> tracking on s-band, like I am, I can give more advice. I am using a
> 1.2 metre dish. In particular the modification for larger feeds,
> calibration due to offset feed and real world low earth orbit tracking
> problems.
>
> If you can supply photos of links of the actual dish we may be able to
> help further.
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