DH Satellite 60 Fixed Az-El Mount - Manual (Page 18)

Figure #13
Heavy Duty Feed Strut________________________
We have developed a new feed strut and collar for the
heavier 4 Port Seavey feed assembly. This utilizes the
rectangular aluminum tube for the feed strut. Figure
#12 right shows the sketch of this feed assembly; it is
very simple to install. Each strut has 2 - 5/16 x 2 l/4”
bolts to attach to the feed collar. Now attach one of
the angle brackets (2" x 2") to the antenna with the
1/2" x 1 1/2" bolts. Notice that angle bracket has two
holes. You will use the bottom hole. The top hole is
for an optional heavy duty Chaparral type feed. Next,
attach the base of the strut to the angle brackets with
the 5/16 x 1 1/2" bolts supplied. Align the feed to
point directly at the center of the antenna. Now mea-
sure the focal length to the front of the sealer rings.
(Seavey recommends f/l is measured to front of scalar
ring.)
Figure #12
Seavey feed collar
Ku Band Feed Assembly-----------------------------
After the assembly is complete, we recommend you "string the antenna." Simply run a string from
a back brace across the front of the antenna to the brace 180 degrees apart. Now do this with each
brace. If the strings all meet in the middle and no pressure is on any of them, the antenna is perfect
and no further work needs be done. If one of the strings is not close to the others, then step back and
sight across the dish and see where you will have to push with the back braces. Only make small
adjustments at a time and remember to start with all braces loose. After you are sure the antenna
surface is flat, you should double check to see that the feedhorn is set at the proper distance, then
check to see that it is pointed at the center of the antenna. In our years of setting up antennas, these
three items seem to cover over 98% of all problems of picture quality.
Fine Tuning the Antenna--------------------------------
Figure #14
Page 13
When using the Ku only feeds, you will be using the C14F feed plate and tri-collar. See Figure
#13. First, attach the flat tri-collar to the feedhorn as follows: attach the first two pieces by using the
8-32 x 1" screws provided. Now slide the collar onto the feedhorn and add the third piece; tighten
evenly. Attach the tri-collar to the larger horseshoe collar by the 8-32 x ¾” bolts and nuts; tighten
down. You can adjust polarity by loosening these nuts and rotating feed. Finish by assembling the
struts to the feed collar as shown in Figure 14. (Fig#14 shows single Ku feed inserted in collar)