John,
I did not know the EMOTATOR was available in North America. It sounds ultra-cool and like another item I need to lust after - truly a BMW of rotators. Is there any place on the web to learn more?
73,
Joe kk0sd
AMSAT # 21357 - Not near as old as 439!
_____
From: John Beanland [mailto:spectrum.ma.ultranet@rcn.com] Sent: Monday, September 10, 2007 9:44 AM To: Gary "Joe" Mayfield Cc: 'Eric Christensen'; 'AMSAT-BB' Subject: Re: [amsat-bb] Re: Rotators
++++++++++++++++++++++++++++++++++++++++++++++++++++++ At 22:14 9/9/07 -0500, you wrote:
If by available you mean currently made -- Alpha Spid is probably the Lexus of AZ/EL rotors - http://alfaradio.ca/alfaspid-azel.html It is the one I lust after -- but my Yaesu has done just fine. 73, Joe kk0sd
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 10th September 2007 KK0SD de S.I., Joe,
Be careful with the Alpha Spid. Check the fine print in the specification.
Last time we checked it was designed as, and built as, a 12 volt motor device. Unfortunately 12 volts does not give sufficient acceleration to track high elevation angle passes when the bird is "high in the sky". Their solution is to increase the power supply voltage; they give performance figures for 18 volts and also 24 volts supply. The 24 volts supply is needed to track the very high angle passes. There is no mention of temperature rise (and reliability?) with 18 or 24 volts supply. Note: It uses DC motors so the torque and available acceleration increase with applied voltage. But do you want to apply 50% or 100% over-voltage to get your required performance?
A much better choice, in the Cadillac class, is the EMOTATOR EV-800-D7X. This uses 24 volt DC motors. There is also a "gold plated" version, the EV-800-DX; this is a BRUTE. Both of these models are compatible with control systems (NOVA, Uni-Trac, SatPC32, and many more) that are "standard" in the Amateur community. The EMOTATOR control box accepts both 115v and/or 230v AC primary power.
These twin axis rotators will happily swing a 6ft solid dish without any complaints. We supply them to our weather satellite system customers and also to government customers, who use a 7.5ft dish for S-band telemetry reception. Tracking performance is excellent. When driven by Uni_Trac or similar (10-bit or greater A/D) unit, the overall (both axes) system tracking hysteresis is about 1.5 degrees RMS.
The EMOTATOR rotators are available from Spectrum International, Inc, Concord, Mass.
73s, de John G3BVU/W1 amsat 439 (a very old number).
Yours truly,
C.J.Beanland, MSEE, C.Eng., MIEE, MRAeS. Sales Manager, Spectrum International,Inc. spectrum.ma.ultranet@rcn.com P.O. Box 1084, Tel: (978) 263-2145 Concord, Mass. 01742. Fax: (978) 263-7008