[ntp:questions] (no subject)

Miguel Gonçalves mail at miguelgoncalves.com
Mon Sep 12 11:10:55 UTC 2011


Hi again!

I forgot to add to my last message the following.

After startup I am getting this

oncore# uptime; ntpq -p
11:07AM  up  3:38, 2 users, load averages: 0.01, 0.05, 0.02
     remote           refid      st t when poll reach   delay   offset
jitter
==============================================================================
oGPS_ONCORE(0)   .GPS.            0 l    4   16  377    0.000   -0.001
0.001
 canon.inria.fr  .GPSi.           1 u   15   64  377   56.045    3.757
0.232
 ptbtime1.ptb.de .PTB.            1 u   20   64  377   65.055   -0.069
1.043
 ntp.inrim.it    .CTD.            1 u    2   64  377   51.213    0.092
0.572
 ntp02.oal.ul.pt 194.117.9.137    2 u   44   64  377   10.194   -0.448
0.465
 ntp04.oal.ul.pt 194.117.9.138    2 u   38   64  377   10.245   -0.093
0.470
 Router7.Lisboa. 193.136.250.246  2 u    8   64  377    8.775    0.123
0.083
 Router15.Porto. 193.136.250.246  2 u    2   64  377   12.667   -0.159
0.521

I averaged my position for 24 hours using Syntac and I will now let it run
for a few days to check the peer stats.

Care to comment the above? I might be missing something...

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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