[amsat-bb] Re: G5400B Rotor Problem

Alan wa4sca at gmail.com
Sun Nov 25 13:26:14 PST 2012


The fact that it works OK from S to N but not N to S argues that it is not
in the meter electronics.  A final test would be to look a the DC output
voltage from the DIN plug and compare the two.  You will be seeing volts,
not degrees, but they should smoothly track, and with a few measurements,
you should be able to calibrate one against the other.  They get their
information from the same 500 ohm pot in the rotator, but different
amplifiers. If they track, it is the reference pot.  If they don't, it is
the meter.

Replacing the pot is not hard, but a messy, tedious job.  You used to be
able to get the pot from Yaesu for about $10, and there are some places you
can Bing which show you how to open up the unit.  

73s and good luck.


-----Original Message-----
From: tokens at myranch.com [mailto:tokens at myranch.com] 
Sent: Sunday, November 25, 2012 3:00 PM
To: APBIDDLE at mailaps.org; amsat-bb at amsat.org
Subject: Re: [amsat-bb] G5400B Rotor Problem


Thanks for the answers. The rotor goes through its 360 just fine. The 
problem is that half way through, when it should read 360 it reads 345. 
There is a nonlinearity in the readout.


-----Original Message----- 
From: Alan
Sent: Sunday, November 25, 2012 3:20 PM
To: tokens at myranch.com ; amsat-bb at amsat.org
Subject: RE: [amsat-bb] G5400B Rotor Problem


To answer the last question, the "out voltage adjust" is for the reference
voltage from the 9-pin DIN connector used with computer control.  It has no
effect on the meters.

I had that rotator for years, before replacing it about 15 years ago.
Unlike some of the other similar Yaesu rotators, the azimuth rotator in the
5400B does not have limit switches, though the elevation rotator does.  (See
schematic)  As I recall, the full mechanical swing is a bit more than 360
degrees, but not the 450 degrees of later units.  The stop to stop method
doesn't work well.  I would set the left limit as you stated, and then
visually look at the antenna as you step it to the right.  In particular,
see what the meter says going through north, then when the antenna swings
around to south again.  With it fully CCW, find a place in the yard where
you are looking down the boom.  Raising the elevation to 15-20 degrees will
help.  Swing it CW 360 degrees and it should look the same.  This should be
a more accurate way to calibrate the 360.  Let us know what happens.



-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of tokens at myranch.com
Sent: Sunday, November 25, 2012 12:31 PM
To: amsat-bb at amsat.org
Subject: [amsat-bb] G5400B Rotor Problem

Hi all,

Trying to get a G5400B rotor going but having some calibration problems with
the azimuth settings. With power off and the rotor set at the left hand
position, I adjust the needle to read 180. When the power is turned on the
reading goes to about 182. I then let the rotor go all the way to the right
180 mark and adjust the full scale pot to read 180. The problem is when the
rotor is half way around and should be reading 360 it actually reads 345.
Any ideas on what I should be looking at? Also there is nothing in the
manual to suggest what the "out voltage adjust" pot is supposed to do. What
is its function?

Thank you for any advice.

73 Al W8KHP
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