[time-nuts] GPS antenna??

Azelio Boriani azelio.boriani at screen.it
Tue Apr 9 05:56:42 EDT 2013


One satellite, OK, but before a GPSDO can use 1 satellite it must have the
normal satellite visibility to complete the autosurvey (usually 10K seconds
long). You can enter the exact lat/lon, if available, and start the 1
satellite operation (known as position hold mode) at once but, usually,
surveyed coordinates of a new antenna installation are not available.

On Tue, Apr 9, 2013 at 10:27 AM, Grant Hodgson <grant at ghengineering.co.uk>wrote:

> Alan
>
> As has already been stated by others, if the purpose of the GPS signal is
> for a GPSDO, then putting an active patch next to a SW facing window should
> work fine.  No need to re-radiate.  You only need to receive 1 satellite in
> order to get a timing signal - more satellites will give better (lower)
> jitter/ADEV, but if you just want an accurate frequency source for a
> counter or signal generator then the setup you describe should be fine.
>
> If that's the case, then it might be worth taking a Rubidium source as a
> higher-performance back-up than the GPSDO in holdover, although some GPSDOs
> are more equal than others in holdover performance.
>
> regards
> Grant
>
> Quoting time-nuts-request at febo.com:
>
>>
>> Hi all an interesting problem you may have encountered, I want to use a
>> GPS
>> frequency standard inside a building with no opening windows (opening
>> windows are known as air conditioning in the UK :-))  )
>> This is part of a two day amateur microwave conference so we should have
>> the
>> expertise.
>>
>> I intend to try and pass the signal through a a double glazed glass window
>> unit (hopefully not metalised) using a couple of patch antennas. The outer
>> GPS antenna is active so will need  a 5v supply via an inserter. Inner
>> patch
>> active, outer patch passive to avoid problems of feedback. Main antenna
>> can
>> be shielded from the "coupling" either physically or with a slab of
>> absorber.
>>
>> Has anyone tried this?.... does it work?.....any gotchas?
>>
>> Thanks
>> Alan
>> G3NYK
>>
>>
>>
>>
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