[ntp:questions] (no subject)
mail at miguelgoncalves.com
Mon Sep 12 11:06:03 UTC 2011
Thanks a lot for your input!
I am checking my clockstats file to see how many satellites my current
chinese made antenna placed indoors is seeing during a 24 hour period. If it
sees enough an external antenna might not be needed.
Do you agree?
I know an external antenna on a mast is way, way more cool (I would say
sexier, but I would be exagerating). Did you have a good laugh with my
2011/9/11 Chris Albertson <albertson.chris at gmail.com>
> 2011/9/11 Miguel Gonçalves <mail at miguelgoncalves.com>:
> > Hi!!
> > My Motorola Oncore UT+ is working fine and I am using a cheap magnetic
> > I want now to buy a better quality antenna for outdoor use.
> > Any suggestions?
> Any of the "timing antenna" are good. Maybe they are better because
> they are a helix type antenna but the most important part is the shape
> of the plastic radome. It's pointed so snow and bird poop does not
> accumulate. Also they are all designed to mound to a standard pipe
> so you can use a length of 1" galvanized pipe as a mast and run the
> cable down inside the pipe. Be sure and ground the pipe and add a
> lightening arrester to the cable run
> Look on eBay for "lucent GPS Timing Reference Antenna 26db Gain"
> Expect to pay about $25, more or less plus ship. and it you are
> willing to drill some hole inn the pipe flange they mount to a
> standard hardware store $4 part. Otherwize you can spend $$ on a
> custom stainless steel mount. Also you really do want a good cable
> with a "N" type connector and not adapters. The N type is waterproof
> and uses o-rings. After you get the cable indoors use whatever
> connectors you like but N is best for outdoors
> That said. I thin there are better antenna that have higher gain and
> can drive a longer cable, Here is one example
> ebay #180721168817
> But the Lucent parts are very common and cheap and you can always
> place the UT+ close to the antenna, maybe right after the antenna lead
> enters the building. That is what I did, then I run cat-5 wire to
> carry the PPS and serial line to the computer. Antenna lead cable has
> so many dB per door of loss. You have to look it up for your cable.
> For longer runs (like 50 to 100 feet) you can get low-loss cable but
> the stuff is expensive.
> It's an exercise in trade offs. Get a higher gain antenna and be able
> to drive lower cost or longer cable, use a short cable and cheaper
> antenna. As long as the gain at the GPS receiver is within spec you
> care OK, the UT+ does not care how you do it. The big advantage of
> the timing antenna is that you cam place it high on a mast and being
> pointed "stuff" slides off.
> You will need to measure or estimate the cable delays
> Chris Albertson
> Redondo Beach, California
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