ENCODER CALIBRATION FOR AZ & EL
1/ PLEASE READ COMPLETELY BEFORE START OF CALIBRATION
THIS ONLY NEED TO BE PERFORMED ONCE IN THE LIFE TIME OF THE iBUTTON Cell (approx. 8 to 10 Years), or Until Something is changed in the field that will alter the gearing ratio.
2/ Rotate Dish, or Array, to a “0” (zero), degree position. This position can be any position that is convenient for you ……… near your moon rise location for example. At this point of calibration it does not matter
3/ Depress the “ZERO”; normally open push button, SW‑2 on schematic. Now depress the MPU reset (RESET); SW‑1 on schematic. This operation clears the MPU registers and clears “touch memory” to zero.
4/ Using a very accurate compass (I borrow a surveyors compass), rotate the Dish exactly 360 degrees from the “zero” position.
5/ When 360-degree position is located, depress the “full‑span” (FULL), normally open push button, SW‑3 on schematic. Again depress the MPU reset, SW‑1 push button. This forces the MPU data registry to the “touch memory”.
You should now be calibrated “exactly” 0 to 360 degrees. Do NOT depress any more switches.
6/ Make sure your computer clock is accurate to time and date before continuing. Computer clock should be within one second of correct time.
7/ Bore Sight the Dish (array), on the moon, using echoes, or peak on sun-noise. Write down the exact position of the moon on the piece of paper. Disregard the dish position indication at this time.
8/ Without moving the Dish, or Array, depress the AZ switch on the front of the control box and rotate knob until indicated position matches exactly the position noted above.
THE SYSTEM IS NOW CALIBRATE TO AZ POSITIONS
There are other methods, or techniques, for doing the same thing as described above and you may chose your own method.
For example: I used the SUN using peak sun noise on 23cm. This is very, very sharp with a 25′ Dish.
The most accurate method is to use the “surveyors compass” IF you know EXACTLY where YOUR “true” north is relative to Magnetic North.
I have NEVER recalibrated my system since the initial calibration over four years ago. Just be sure of your angles when setting the 0 to 180 degrees, or 0 to 360 degrees are very
Accurate. Within 0.05 degrees if possible.
You may remove power (VCC), voltage from the complete system it will
remember where it was when you re‑establish supply voltage.
Just remember if you MOVE the Dish, or array, without VCC applied to the system
you will have to “BORE SIGHT” the system again. NOT RECALIBRATE.
I have a relay in my VCC supply that will not allow me to move the Dish unless VCC is applied. I also have an over‑ride switch that will allow me to move without VCC. But that switch is hidden inside the control box with SW‑1, 2, and 3,
Elevation calibration is performed nearly the same way as AZ calibration.
Locate the Inclinometer so it may be rotated EXACTLY 360 degrees. Depress the “zero” switch and next the “reset” switch.
Rotate the Inclinometer exactly 360 degrees and depress the full span switch. Now install on the system.
Remember that in TRACKING SETUP you must be operating in the BIN mode and 0degrees offset until calibration is completed.
After calibration is completed you can set your offsets and then using the EL, or AZ switch on the front panel reposition the display to indicate the true settings.
Canadian Amateur Radio Station VE1ALQ & VE9DW
Click here to forward on to the next topic about Voltage Source and Pre-Amplifier Installation.