Hi Worth noting:
The "mid class" antennas are not a lot different electrically than the "low end" antennas. The main differences are mechanical: 1) You get a much more weather tight housing 2) You get a rational way to mount the antenna 3) There's a connector on it so you can put a good piece of coax on it 4) The housing *may* be more immune to snow / ice buildup and bird nests RDR Electronics on the usual auction site appears to be selling some nice ones at the moment. Bob On Sep 15, 2013, at 4:36 PM, Hal Murray <[email protected]> wrote: > > [email protected] said: >> Well, I need something that I can put outside, in the weather, with my >> verticals, and other antennas. I am a Ham radio enthusiast, and I want >> something I can properly mount and can be an all-weather device and can live >> happily 'in the farm' so to speak. > > I split GPS antennas into 3 clumps. > > At the low cost end are the small "mouse" or "hockey-puck" type units, > usually with a magnetic mount. They typically come with 10 or 15 feet of > thin (lossy) cable. Ballpark price is $10. > > In the middle are the typical cones that you see on cell phone stations. The > Lucent 26 dB ones are common on eBay. Ballpark price is $50. The same or > very similar thing is also available with different brand names. Some of > them come with a pipe mounting setup such that the coax and connector is > inside the pipe and out of the weather. > http://www.megapathdsl.net/~hmurray/time-nuts/Lucent-Antenna.jpg > > At the top end are the choke ring antennas intended for surveying. They are > mostly out of my price range so I haven't looked carefully. > > ---------- > > I haven't seen a GPS antenna without an amplifier, but I haven't been > looking. They also include a filter. See the LightSquared flame-wars for a > discussion of filters. > > I think the choke ring antennas usually let L1 and L2 through while most > others are L1 only. > > The other important consideration is the sensitivity of your receiver. Every > couple of years a new generation comes out that is a few dB better than the > previous ones. (Has anybody seen a Moore's Law type graph?) > > Modern receivers are sensitive enough to work indoors with a non-fancy > antenna, at least most of the time. YMMV etc, and "indoors" probably doesn't > include buildings with a lot of steel. It doesn't cost much to try. > > If you have an old recycled GPSDO such as a TBolt or Z3801A, the receiver is > much less sensitive and a good antenna position helps a lot. Of course, it > also depends upon what you want to do and/or how nutty you are feeling. > > There is yet another dimension. GPS receivers come in two modes: navigation > and timing. Navigation units need 3 or 4 satellites to figure out where (and > when) they are located. The timing units assume they are not moving and that > they know their location. They should be able to maintain timing with only 1 > satellite. > > > -- > These are my opinions. I hate spam. > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
