Hi Machining a chunk of Plexiglas sounds like more trouble that I would want to go to for a cheap choke ring setup.
Maybe a hemispherical Plexiglass serving bowl .... Bob On Mar 14, 2010, at 3:42 PM, b...@lysator.liu.se wrote: > Hi, > > I have two AT575-90s - the Aeroantenna L1 chokering - resold by CMC, Leica > and others. They work really well as witnessed by others here. One nice > touch is that they - at least the CMC badged - come with a > "marine"-thread to 5/8" survey-mount adapter. > > However, this model is not present at > > http://www.ngs.noaa.gov/cgi-bin/query_cal_antennas.prl?Model=AER > > so it does not count as a true geodetic antenna. ;-) > > The cone cover is indeed good. Snow/ice-buildup would have been a > showstopper this year in Sweden. For real geodetic use "spike"-cones are > long out of fashion. From my understanding a thin plexiglas makes good > cone material. Combine a halfsphere (upper) with a suitable lenght "tube". > Make the center of the sphere as close to the phase center of the antenna > as possible. > > Here is an illustration. > > http://swepos.lmv.lm.se/stationer/opp.htm > > -- > > Björn > >> Hi >> >> All of these gizmos are going to work better outdoors than indoors. Coming >> up with a rainproof / bird proof / bug proof cover for the choke ring that >> also is rational at RF is one more "gotcha". Both loss and dielectric >> distortion effects are worth worrying about. >> >> Bob >> >> >> On Mar 14, 2010, at 1:23 PM, gandal...@aol.com wrote: >> >>> In a message dated 14/03/2010 15:46:55 GMT Standard Time, >>> cfhar...@erols.com writes: >>> >>> I would call those aluminum cake, not pie, pans. It looks like you >>> bought >>> a set for making wedding cakes. >>> >>> Is there a different definition of "pie" in G8 land? >>> ----------------- >>> Hi Chuck >>> >>> No other definition that I'm aware of, other than David's of course, but >>> I >>> was just replying to Brian, KD4FM, so I guess that makes it a US of A >>> definition:-) >>> >>> regards >>> >>> Nigel >>> GM8PZR >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.