[time-nuts] First Post from Max NG7M

Bob Camp kb8tq at n1k.org
Fri Apr 24 23:01:28 EDT 2015


Get it as high as you possibly can. 

Protect it from lightning if you get it high (or even if you don’t get it all the way up there).

Your LMR-400 will have about 8 db of loss at the max height and about 5 db at the gutter. Neither
one is anything to worry about. 

RF wise, your house isn’t much of a block for 1KW on 160 meters. It’s not even much on 80 or 40. 
If you have a problem, you can fix it after the fact (that’s why filters were invented …). 

The bigger question is - do you spend $100 and get a *good* antenna ….

> On Apr 24, 2015, at 8:59 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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