DH Satellite 1PC or 8PC 4.2m & 4.5m 48 Polar/Fixed Mount - Manual (Page 12)

ADDITIONAL FINE TUNING TECHNIQUES
To receive the optimum from your antenna, you must take time to fine tune the antenna. What are the antenna
adjustments? They are: make the front surface flat, be sure the feed looks at the center of the dish, and set the proper
focal length. You must also be pointed at the satellite and have the feedhorn skew properly adjusted.
Many of the adjustments are done without any measurement of the signal, and in fact require no signal at all.
The adjustment of making the front surface flat, adjusting the focal length, and aligning the feed will be done without
signal. You will use the strings and the back braces to make the dish flat, a focal finder and measure tape to align the
feedhorn to find center, and set the focal length using a measure tape to measure from dish to feedhorn. You will use a
satellite tool to locate signal in further steps of fine tuning.
We feel that you must use strings to assure the front of the dish is flat. The strings must be taut and run from
brace to the opposite brace at 180 degrees. A larger dish with 8 braces needs four strings. Do all adjustments with the
braces loose. The strings must touch at the center, if they do not, sight the dish from the side to see which braces should
be slightly adjusted to make the front surface of the antenna perfectly flat. CAUTION: do not over tighten the bolts that
hold the dish to the ring as they can distort the dish.
The easiest way to assure yourself that the feedhorn is looking directly at the center of the antenna is to use a
Focal Finder (SEE PHOTO “A” BELOW) or to make a tool to assist in finding the center of the antenna. You can if no focal
finder is available, cut a 1” X 4” board to the length of the antenna’s focal length. Held vertically against the feed it
should point at the center of the antenna, this will be true at the horizontal plane as well.
DH recommends using an A1 Turbo S2 made by Applied Instruments or another tool such as a spectrum analyzer
to locate your satellite signal in order to complete the following steps:
Setting the Azimuth: To set the azimuth of the system you will use the base can and a tool to locate and
measure signal. Find a satellite signal using the A1-Turbo or another satellite tool that will show signal spiking. Any signal
strength will work. This is your reference point. Now you will go from bad signal to bad signal. From this reference point
you will move the antenna left of the reference point to see if the signal gets better or worse and right of the reference
point to see if this makes it better or worse. When you see the location of the base can for the best signal, you will
tighten down the set screws on the base can. (Special Note: It is best to make a mark on the pole and base can to
reference your starting point before making any moves with the base can. Remark your base can and pole so that you
now know the location that is allowing the strongest satellite signal.)
Setting the Elevation: You will use the turnbuckle assembly to make this adjustment and again you will go from
bad to bad signal and find the center point with the best signal strength. Again, to make this adjustment you will only
use the turnbuckle. It is best to mark the starting point of the threaded rod or count the turns so you know exactly
where you started before making slight adjustments with the turnbuckle assembly.
Skewing the feedhorn: You will rotate the feedhorn again going from left or right of the marked reference
location for your feedhorn to find your strongest signal. Once you find your strongest signal tighten down into place.
Keep in mind when you are making these last “Additional Fine Tuning Techniques” very small moves will be
needed to make the best improvements in signal strength.
PHOTO A
Focal Finder to Locate
Center of Antenna
A1 Turbo S2 Made By Applied
Instruments
Page 8A