DH Satellite 1PC or 8PC 4.2m & 4.5m 48 Polar/Fixed Mount - Manual (Page 10)

FINE TUNING THE ANTENNA
Plan to take an extra hour of your time to get the most from your antenna. We recommend using a Spectrum
Analyzer to do this or A1 Turbo S2 made by Applied Instruments.
With each adjustment you make you will be able to see your increase/decrease in gain. To begin you must
string the antenna. This is done by simply taking a string, tying it to one brace and running the string across
the front of the antenna to the other brace at 180 degrees and tying it so it is taut. Now tie another string to a
brace 90 degrees from the first brace and running it to the corresponding brace 180 degrees away. Be sure you
put the string on top or under the other string so as to not touch each other. When done you should have two
strings at 90 degrees and they should meet in the center of the antenna. (Ideally you should use four strings at
approximately 45 deg. apart.) If the strings don't touch at the center, then you will have to do some adjusting
with the back braces. Be sure your strings are taut. Stand back about 30 ' and sight the antenna again and see
where you must apply pressure with the braces or relieve the pressure from an area. Go ahead and make small
adjustments with the back braces, each time checking with the Spectrum analyzer to see that you are increasing
the gain of the antenna.
PREPARING THE FEED ASSEMBLY
You will find below the focal lengths and focal length/diameter ratios for our commercial 4.2m and 4.5m
antenna. This information is necessary to set the antenna and feed up properly.
14' (4.2m) 57.6"f/l .34 f/d 14’ 9” (4.5m) 57.6”f/l .33 f/d
Measuring f/l
Your DH representative has provided you with the correct feed collar to mate to the feed horn that you
have ordered for this installation. In the event DH was not aware of your feed horn being used, the
default C14F collar is supplied. Take the collar and set it on the back of the scaler ring of the feed horn.
Turn it until all three holes line up between the two and insert the 1/4 "x 3/4" bolts thru the scaler ring
and then thru the collar. Fasten with the 1/4" nuts. Most C-band and dual feeds have a 3-bolt pattern on
the scaler just for this (See FIG. 18-21). Now, slide the end of the strut thru the feed bracket as shown
in FIG. #19 and attach each leg w/ 2- 1/4” x 1 1/2” bolt & nut. Do this on all four struts. Place the
flattened end of the struts onto the antenna and use the 1/2 "x 1 1/2" bolts to fasten to the dish. Use
every other hole on the face of the antenna. Check to see the feed is at the focal length, and then tighten
all bolts. The actual focal length should be 1/4" inside the waveguide for C-band.
C14F COLLAR
C14F COLLAR
& STRUTS
C14FHD COLLAR
& STRUTS
C24HD COLLAR
& STRUTS
SPECIAL NOTE: FIG. #18, #19, & #20 are used primarily with Chaparral and
ADL C band and C/Ku band feed horns. FIG. #20 is a special order Heavy Duty
feed strut system and may be purchased at an additional cost.
FIG. #21: Our C24HD is a special order Heavy Duty system set up for Seavey
manufactured C & C/Ku band feeds. This may be purchased at an additional cost.
FIG. #18 FIG. #19 FIG. #20 FIG. #21
Page 7
35 3/4” OR 57 3/8”