Best approach is to email the manufacturer directly, this sort of
kit isn't a consumer product which you can buy off a website.
They are very common and well-known across industry, but are
usually furiously expensive. The new application for the tiny ones
(< 8 inches) is turning solar panel arrays, and the high volume
of production means the prices have fallen. The larger ones are
used for cranes and in machining systems for example. They combine
a precision ground bearing ring with (usually) a worm drive.
The usual approach is to fit them to a ring flange at the top of
a support pole, and fix the other side to a machined flange on a
90 degree trussed elbow, then fit another to a machined flange on
the vertical face of the elbow, and the other face to a flange
attached to the dish/counterweight/saddle. Nice easy
fabrication/welding/machining job. There are some videos on
Youtube about using them for EME systems.
A magnetic absolute encoder chip like an AS5048A can then be used
(on a compliant mount) for 14-bit rotational feedback. OK, it
aneeds a bit of precision machining to make the mount, but for £15
or so for a complete PCB, chip with SPI or I2C interface and a
diametrical magnet, they are excellent value. https://www.mouser.co.uk/datasheet/2/588/AS5048-EK-AB_Operation-Manual_Rev.1.3-775916.pdf
On 11/12/2019 11:15, Don Hawbaker
The link to the web site is not very
helpful. Exactly which model is suitable for an EME dish? It’s
not at all clear how you mount one of these things to a pole.
How big, how small? You say $400 but I see no price list
anywhere. Shipping costs from China? You said pulse interface.
I cannot use a pulse interface and I don’t trust them. There
are few controllers that will handle pulse. What other
interfaces are there? Are you using just one side of a
quadrature incremental output? Is there a way to mount other
These things are not going to be used until
better sources and more information are available.
If you want precision and extremely good value for money
you should look at Slewing drives from China, they are
10 times stronger than ANY ham rotator, easy to fit and
have very low backlash. The 3 inch ones are fine for a
3m dish in a windstorm and cost about 400 USD. You can
get AZ or AZ/EL, they have pulse outputs and integrated
motors and gearboxes. I have ordered a 7 inch AZ/EL
drive for my 4.5m dish which I will build in the Spring.
Two companies that I or friends have had dealings with
are Sunslew Ltd and Coresun drive which is a new company
set up by former sunslew employees.
Prosistel PST61 is strong, I have one on my 2m EME array
but I have to say that the Create RC5B3 and ERC-M
combination is much smoother. I have had that rotator
for a very long time and it has had some big antennas on
it over the years. It is as good as it has always been
and I am still using the original pot. The PST61 needs
care to prevent pot failure due to water damage but
touch wood I seem to have found a method that prevents
this. I have a SPID-RAK but I have not used it yet. I am
expecting problems. Looks like another chat with Dom
F6DRO is on the cards. I hope to use this with a 2m dish
for 23/13 when I find another high enough mast to get
the thing above the tree line.
it needs 0.1 degree resolution
display, software settable end stops and offset,
motor speed control for
start-stop, and RS232 or USB interfacing for PC
Naw, you need a bike. Tyre off wheel, wheel
over pole, big sprocket on a mount, bit of wood
etc then a couple of bike chains and away you
What did we ever do before