murray@src.dec.com (Hal Murray) (11/08/90)
I was hiking near the top of Black Mt the other day. It's high and has line of sight to much of the Bay area so I wasn't surprised to see that there are lots of antennas up there. There were also two large (~15 ft square) panels that I assume are reflectors. One points roughly north, the other south. Anybody know what they are reflecting and to where? The weird thing about them is that they are not back to back, but more like front to front with a big offset. It might be a double bounce, but that seems very strange. I couldn't see that they were pointing anyplace interesting.
sturdevant@iccgcc.decnet.ab.com (Mike S.) (11/09/90)
In article <1990Nov7.203538.4076@src.dec.com>, murray@src.dec.com (Hal Murray) writes: > I was hiking near the top of Black Mt the other day. It's high and > has line of sight to much of the Bay area so I wasn't surprised to > see that there are lots of antennas up there. > > There were also two large (~15 ft square) panels that I assume are > reflectors. One points roughly north, the other south. > > Anybody know what they are reflecting and to where? > > The weird thing about them is that they are not back to back, but more > like front to front with a big offset. It might be a double bounce, > but that seems very strange. I couldn't see that they were pointing > anyplace interesting. Maybe laser monitors for earth movement. Go fast. Take chances. Mike S.
tomb@hplsla.HP.COM (Tom Bruhns) (11/10/90)
murray@src.dec.com (Hal Murray) writes: >I was hiking near the top of Black Mt the other day. It's high and >has line of sight to much of the Bay area so I wasn't surprised to >see that there are lots of antennas up there. >There were also two large (~15 ft square) panels that I assume are >reflectors. One points roughly north, the other south. Sounds like your double-bounce idea may be the right one... Ever come across any cube corner reflectors? I've seen them on occasion near airfields, apparently used to mark locations for aircraft and perhaps also for calibration/continuous checking of the airfield radar...
thomas@mvac23.UUCP (Thomas Lapp) (11/10/90)
murray@src.dec.com (Hal Murray) writes: > I was hiking near the top of Black Mt the other day. It's high and > has line of sight to much of the Bay area so I wasn't surprised to > see that there are lots of antennas up there. > > There were also two large (~15 ft square) panels that I assume are > reflectors. One points roughly north, the other south. > > Anybody know what they are reflecting and to where? I'll take a stab at this one based on another reflector I know about. In the Morgantown, WV area, they (the telco) built a switch which had a microwave transmitter on the roof for long-distance calls. The location was such that it could not "see" the next transmitter which was on a mountain about 10 miles out of town. However, there WAS a hill which the local switch COULD hit, and could reflect to the out of town mountain. My guess is that you are seeing the same thing: a microwave reflector for (old?) phone equipment. - tom -- internet : mvac23!thomas@udel.edu or thomas%mvac23@udel.edu (home) : 4398613@mcimail.com (work) uucp : {ucbvax,mcvax,psuvax1,uunet}!udel!mvac23!thomas Location : Newark, DE, USA Advise: : Be slow to anger, and quick to praise -- The UUCP Mailer
bill@videovax.tv.tek.com (William K. McFadden) (11/10/90)
In article <1990Nov7.203538.4076@src.dec.com> murray@src.dec.com (Hal Murray) writes:
->There were also two large (~15 ft square) panels that I assume are
->reflectors. One points roughly north, the other south.
->
->Anybody know what they are reflecting and to where?
The ones I've seen around here were used as passive repeaters for the phone
company's microwave links.
--
Bill McFadden Tektronix, Inc. P.O. Box 500 MS 58-639 Beaverton, OR 97077
bill@videovax.tv.tek.com, {hplabs,uw-beaver,decvax}!tektronix!videovax!bill
Phone: (503) 627-6920 "The biggest difference between developing a missle
component and a toy is the 'cost constraint.'" -- John Anderson, Engineer, TIhbg6@citek.mcdphx.mot.com (11/12/90)
>In article <1990Nov7.203538.4076@src.dec.com> murray@src.dec.com (Hal Murray) writes: >->There were also two large (~15 ft square) panels that I assume are >->reflectors. One points roughly north, the other south. >-> >->Anybody know what they are reflecting and to where? There used to be one located near the Navajo Army Depot west of Flagstaff Arizona. It was used as a passive repeater to bounce several TV stations from Mount Elden several mile away into a little hidden valley. Before I noticed the reflector, I wondered why all of the TV antennas were pointed in the wrong direction and inclined about 50 degrees. I guess the towns folk didn't want to erect 500' towers to watch the family feud. :-)
gnome@olivea.atc.olivetti.com (Gary) (11/14/90)
> In article <1990Nov7.203538.4076@src.dec.com>, murray@src.dec.com (Hal Murray) writes: >> Anybody know what they are reflecting and to where? >> >> The weird thing about them is that they are not back to back, but more >> like front to front with a big offset. It might be a double bounce, >> but that seems very strange. I couldn't see that they were pointing >> anyplace interesting. I think that they are microwave HBO reflectors used to balance the signal strength over a large coverage area. This is for the terrestrial microwave system, not satellite. Gary
paulf@shasta.Stanford.EDU (paulf) (11/14/90)
We maintain a number of ham repeaters up on Black Mountain. The "bounce boards" are apparrently for an FAA microwave link. -=Paul Flaherty, N9FZX | Life is an inherent shift - reduce conflict. ->paulf@shasta.Stanford.EDU |
wb8foz@mthvax.cs.miami.edu (David Lesher,,255RTFM,255rtfm) (11/15/90)
We have one of these on a next door FAA site. I suspect that ours, at least, are not redirection reflectors per say, but rather it has many small corner reflectors within, and is a marker-reflector that puts a bright spot on someone else's display. I say that because: 1) The one here is absolutely vertical. Any 'redirection' bouncing would thus be between two sites, not between the place next door and another. (These 'flyswatters' used to be popular, but are now banned.) Now it is so flat around here that the high spot in the county is the trashpile, thus I doubt this bounce is to avoid Mt. Wilson ;-} 2) The reflector is THICK. It looks to be maybe 4-8 inches front-back. Thus there is room inside the cover for lots of corners. -- A host is a host from coast to coast.....wb8foz@mthvax.cs.miami.edu & no one will talk to a host that's close............(305) 255-RTFM Unless the host (that isn't close)......................pob 570-335 is busy, hung or dead....................................33257-0335