[time-nuts] GPS antenna??

Mark Spencer mspencer12345 at yahoo.ca
Mon Apr 8 18:29:48 EDT 2013


In my experience in the northern hemisphere if the window is more or less south facing and the window isn't coated with something that absorbs RF energy then an antenna located inside and near the window will frequently (but not always) provide enough signal for a GPS timing receiver to work but it may go into "hold over" from time to time.   I'd be inclined to try an inside antenna before spinning my wheels on other solutions.    

As another approach, consider that if the GPS receiver can opperate from external DC power or you can arrange for a UPS to power the GPS receiver and it provides a "hold over" mode you could connect the GPS receiver to a suitable antenna at another location then run it in "hold over" mode while moving it inside.   The GPS receiver specs should provide insight into the accuracy you will get while in "hold over" but physically moving the GPS receiver will likely add some additional error unless the receiver was designed for use on moving platforms.

If you simply need a single reference source to enable a demo or a conference for a limited period of time then the absolute accuracy might not matter much ?

Good luck and best regards
Mark Spencer

> 
> Message: 7
> Date: Mon, 8 Apr 2013 22:29:43 +0100
> From: "Alan Melia" <alan.melia at btinternet.com>
> To: "Discussion of precise time and frequency measurement"
>     <time-nuts at febo.com>
> Subject: Re: [time-nuts] GPS antenna??
> Message-ID: <2E167F4F56A9450B83CC23F01F8BB523 at gnat>
> Content-Type: text/plain; format=flowed;
> charset="iso-8859-1";
>     reply-type=response
> 
> Hi David yes its ferro-concrete which makes quite a good
> screen (a lot worse 
> than domestic brick) but the windows are not coated I think.
> (BT Labs at 
> Martlesham)
> 
> Thanks all for some thought stimulating ideas .....GPSDO
> outside might not 
> be too easy....1U rack case mains powered....no power
> available outside but 
> 10MHz (or 5MHz in this case) coupling through wall or window
> is a lot easier 
> if I had a battery powered unit.....I have a feeling there
> may be battery 
> back-up terminals on it must get the book out.
> 
> The windows are SW I think but give a good view of a
> quadrant of the sky. It 
> will be interesting to see how long it takes to lock up
> compared with an 
> outside antenna.
> 
> Thanks and Best Wishes
> Alan
> G3NYK
> 
> 
> 



More information about the time-nuts mailing list