[ntp:questions] (no subject)

Miguel Gonçalves mail at miguelgoncalves.com
Mon Sep 12 11:06:03 UTC 2011


Hi Chris!

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
statement? :-)

Thanks!

Cheers,
Miguel

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
> antenna.
> >
> > 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
> flange
>  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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