[time-nuts] First Post from Max NG7M

M. George m.matthew.george at gmail.com
Sat Apr 25 00:17:35 EDT 2015

Hi Chris, thanks for the feedback... the cost is not a concern, is making
the run to the peak of the roof worth it as far as the GPS reception /
signal is concerned?  Where I have a clean view south, is it worth it to
run the coax up through the attic and to the peak of the roof so I get a
totally clear 360 view to the north?  If not, it's much easier to put my
mast mount a few feet back on the eve of the roof.

I have the LMR-400 collecting dust and the RG-213 sized N connectors... so
I'll just use what I have handy.


On Fri, Apr 24, 2015 at 8:39 PM, Chris Albertson <albertson.chris at gmail.com>

> What is the problem withplaccing the GPS antenna all the way up on the
> roof ridge?  If you can get an iron pipe and make short mast and place
> the GPS Antenna a few feet above the top of the roof.  Run the pipe
> through the roof into the attic and run the coax cable inside the
> pipe.  This way the coax is shielded from the weather and sun and you
> have a lifetime installation.
> Was the problem the cost of the cable or the loss in that cable?
> Don't worry about it.  If cost is the problem then use the double
> shield Cable TV cable with the swagger-on F connectors.  Yes it is 75
> ohm but this is the cable Trimble recommends.   If the run is very
> long and there is loss, get either a higher gain antenna or an in-line
> amplifier.
> You can work around cost and loss in that cable but you can't work
> around antenna location.  You do NOT need low-loss LMR cable.  RG59
> works.
> On Fri, Apr 24, 2015 at 5:59 PM, M. George <m.matthew.george at gmail.com>
> wrote:
> > Hello Time Nuts!  This is my first post, but I have been lurking about
> for
> > several weeks now... what started out as a project to find a stable time
> > reference for a QS1R I have been running 24x7 for years on the NC7J CW
> > Skimmer server has taking me down a whole to obsession after finding time
> > nuts and GPSDO information.  I now have a clean Trimble TBolt and the
> > Lucent RFTG-u REF0/1 ready to roll... not to mention a couple of
> Raspberry
> > Pi 2's with NTP servers on them setup and ready to accept a PPS signal
> from
> > my new gizmos!  I'm following the path that has been traversed many times
> > before and I appreciate all the info that I have already gleaned from the
> > time nuts list.
> >
> > Anyway, I didn't get the TBolt for free form China, but it' s a clean
> > machine and seems to be settling down nice after running for a few
> days...
> >
> > Another reason for the post here is related to an installation of a GPS
> > antenna on my roof.  I have a $38 ePay bullet that I'm going to put up
> > tomorrow and make a run of solid conductor LMR-400 to the antenna with a
> > nice little J-Pole mount.  Or potentially 2 runs for 2 GPS antennas.
> >
> > I'm lucky to have a southern exposure off the back of house with my ham
> > shack in the raised basement right in the south west corner of the house
> so
> > the new GPS antenna project works out well to keep the coax run short as
> > possible to the GPS antenna. (see the pics attached or link at the bottom
> > of my verbose post here)
> >
> > I'm shocked at how well a cheapie mushroom GPS antenna is doing close to
> > the back of the house on a broom stick at the moment.  Anyway, I know
> that
> > to even think about being a time nut, I need to get a better location for
> > the GPS antenna (two really eventually or a splitter).
> >
> > I have attached a picture of my house and you can pretty much see my
> > options.  Do I go up and simply put the antenna on the roof close to the
> > edge above the rain gutter or do I take it all the way to the peak of the
> > roof where you can see a WX station and dual band antenna?
> >
> > I realize I can calculate the loss in the extra coax, but I'm more
> > concerned about the fact that I have a SteppIR BigIR vertical HF antenna
> in
> > my back yard and I run power / 1KW+ at times on HF (I'm a CW nut!).  The
> > coax run to the top of the eve is going to be about 30-40 feet of coax
> > roughly, if I take it all the way to the peak that's probably another 30
> > feet or so.  70-80 feet max if I go to the roof.
> >
> > Would a true time-nut need to have the bullet antenna at the peak of the
> > root for a true clear view of the horizon even to the north 360 degrees?
> > Will it bug me down the road that I didn't just run the bullet / coax up
> to
> > the peak of the roof down the road, regardless of my concerns about RF
> from
> > my HF operating potentially getting into the GPS antenna? (I'll probably
> > put a voltage limiter on the GPS feed line).  The antenna has a nice
> direct
> > southern view off the eve.
> >
> > Thoughts for a first time poster and time-nut wanna be?  The eve or the
> > peak?
> >
> > Here is a link to the house pic and a few pictures of the TBolt gizmo
> that
> > arrived from China this week:
> http://www.nc7j.com/downloads/NG7M/Time-Nuts/
> >
> > I attached the pics too... is that okay on the time nut list?  Picture
> > attachments?
> >
> > Max NG7M
> >
> >
> >
> > --
> > M. George
> >
> > _______________________________________________
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> > and follow the instructions there.
> --
> Chris Albertson
> Redondo Beach, California
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M. George

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