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Old June 26th 08, 11:19 PM posted to rec.radio.amateur.antenna
amdx amdx is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 349
Default Parabolic Dish Questions


"Dale Parfitt" wrote in message
news:7xR8k.35$wR.10@trnddc07...

"amdx" wrote in message
...
I have a Directv dish 35 inches wide x 20 inches tall 4inches deep.
I calculated the focus as F=D*2 / 16d where D =diameter and d=depth
F=18 inches Ok so far.
How do you find beamwidth? I think the 35" dimension would have a tighter
pattern than the 20 ", but how do you calculate,

Second, The feed antenna, There can be different feeds.
A simple monopole, dipole, biquad, patch, yagi, helix.
How does the feed antenna affect the gain of the dish, if at all?
Yea, it my be difficult to light the yagi or helix, so if you like throw
those out.
Thank You,
Mike


The DirecTV dishes are not prime focus, bu rather offset. If it came with
the original horn mount, use it.


Hey I just found the dish I have it's at
http://www.solidsignal.com/satellite...enna_types.asp
Last dish on the right side of the page, it's called the International
Satellite Dish.
International 36". I note from the picture the feeds don't match, when I got
the dish
the position of the two feeds were reversed.
What can you glean fron this?
Thanks, Mike