[amsat-bb] 24 X 36 inch Dish calculations

["Jack O'Mara" <jomara@xxxxxxxxx>]

Well I survived Dayton and came back with a dish and converter
to compare with my Drake. I picked up a 24 x 36 inch dish and
just tried to determine the focal point and f/d. Here's what I
came up with.

Diameter (equivalent) 37 inches
Depth of dish 5.875 inches
F/D .3935 or .4 
Focal point 14.56 inches

Has anyone done this and if so how do my calculations compare?

If the above is correct then a coffee can feed would work but
with some of the dish missing there would be some extra noise
pickup. A horn feed could possibly be designed that would better
illuminate the dish and cut down on the noise. Has anyone this?
The above is based on a linear feed.

Any feedback?

73
Jack W4AD
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