[time-nuts] First Post from Max NG7M

paul swed paulswedb at gmail.com
Sat Apr 25 15:57:15 EDT 2015


Welcome to time-nuts and you are getting good advice.
As mentioned lmr400 is nice but not warranted. RG6 is the better coax as
far as loss goes. So consider that over 59. Price is pretty much the same.
But do pick up a good grade of either. Not something you may find at a
local store going out of business. I actually run 2 antennas. One 80 ft on
the tower and I do use low loss 1/2" catv cable. Why? It was free and new.
The other uses RG6. Both have been in service a solid 10 years. Most modern
antennas have about 35 db of gain in them exactly to drive losy cable.
Now the next thing you will run into is you simply do not have enough GPS
ports because suddenly you will find you have 3 units and not 1.
I am very satisfied with the 2.5 Ghz splitters you can get. One ports
active to pass power through. I actually use a 8 way with a home brew
amplifier ahead of the splitter to make up for the loss. Son of a gun if I
am just about out of ports!
Anyhow like all things radio and such it just keeps going.
Welcome
Paul
WB8TSL

On Sat, Apr 25, 2015 at 2:11 AM, Chris Albertson <albertson.chris at gmail.com>
wrote:

> The GPS satellites are located to the south all the way down to the
> horizon but to the north they do not extend all the way to the horizon
> unless you live very far south, like in Mexico.    So you may not need
> to see all the way to the northern horizon.  You do want to see the
> horizon to the south.
>
> But more important is that the antenna is away from reflective
> surfaces like metal roof vents and flashings.  The short mast does
> this.
>
> Do you need this?  If you are just trying to keep an HF transmitter
> on-frequency then no.
>
> On Fri, Apr 24, 2015 at 9:17 PM, M. George <m.matthew.george at gmail.com>
> wrote:
> > 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.
> >
> > Max
> >
> >
> >
> > On Fri, Apr 24, 2015 at 8:39 PM, Chris Albertson <
> albertson.chris at gmail.com>
> > wrote:
> >
> >> 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
> >> >
> >> > _______________________________________________
> >> > time-nuts mailing list -- time-nuts at febo.com
> >> > To unsubscribe, go to
> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >> > and follow the instructions there.
> >>
> >>
> >>
> >> --
> >>
> >> Chris Albertson
> >> Redondo Beach, California
> >> _______________________________________________
> >> time-nuts mailing list -- time-nuts at febo.com
> >> To unsubscribe, go to
> >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >> and follow the instructions there.
> >>
> >
> >
> >
> > --
> > M. George
> > _______________________________________________
> > time-nuts mailing list -- time-nuts at febo.com
> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
>
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
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>



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