[amsat-bb] "Trash Can" dish antennas

[RMckni8527@xxxxxxx]

Most larger Navy and USCG ships have "trash can" antennas mounted on the 
flying bridge.  The best way for me to describe them would be to take a metal 
trash can, cut half of the top off, and mount the parabola in the bottom with 
the feed in the open end.  This in effect is like wrapping a "fence" around 
the outside edge of a normal circular dish.  Does this serve to eliminate 
background noise from over illumination of the dish, so the feed only sees 
signals from the front of the focal point?

I don't know the official nomenclature of these antennas, but they're about 
4-5 ft in diameter, painted Navy gray, have gyro stabilized tracking, and are 
always seen in pairs one port, one stbd on the flying bridge.  Not sure what 
they're used for.  They do actually look like a trash can, or maybe more 
closely resemble a tub used for icing down a beer keg.

What are the implications for a dish used on our satellite freqs?  Beneficial 
to explore a similar design?

73's
Ray - WB3ABN
Kingston, WA
----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org