[hpsdr] Gilding the lily: thanks.

[EB4APL]

Jeff,
I agree with Kevin about the GPS receiver.  Simplifying, there are to
kinds of  GPS receiver modules: navigation and timing (and well,
geodetic and so ...).  The common kind is the navigation type, which is
primarily designed to calculate where you are, and the timing type,
which is designed to give you precise time (given you know exactly where
you are).  The difference lies in the firmware, and while one usually
can use a timing rcv for positioning (in fact they can survey their own
position for a long time before giving precise timing), the reverse is
not true, the navigation rcvs, even the ones with 1 PPS output, are up
to an order of magnitude less precise.  The rcvr recomended by Kevin is
a timing one.  (For elaborate discussions on this topic, GPSDO and
precise time and frequency see the timenuts forum).

There are good and very cheap second hand sources of GPS timing rcvs and
hi quality ovenized oscillators in China.  Check ebay items
300355981024, 260359784174 and 180401766962 as examples.

Best regards,
Ignacio, EB4APL


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Kevin Wheatley wrote:
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>
> Hi Jeff
>
> The eBay item looks pretty good, however if I were you I’d go for one 
> of these:
>
> http://www.dpieshop.com/trimble-resolutiontrade-gps-timing-receiver-p-253.html
>
> together with this small active antenns:
>
> http://www.dpieshop.com/trimble-miniature-5v-gps-antenna-smb-connector-rohs-5623700-replacement-p-292.html?osCsid=g7c30k8j8ghss3uv5u001uqd32
>
> These two items will provide you with the main GPS hardware, the next 
> thing you will want is a good 10Mhz Xtal oven, these turn up on eBay 
> frequently, here’s one for example:
>
> http://cgi.ebay.co.uk/10MHZ-XTAL-OVEN-OSCILLATOR-blb18_W0QQitemZ350202763265QQcmdZViewItemQQptZUK_ConsumerElectronics_SpecialistRadioEquipment_SM?hash=item5189b61801
>
> A simple circuit to ‘steer’ the 10Mhz Xtal with the 1pps pulse from 
> the gps is all you need. As discussed yesterday.
>
> There are many other implementations to achieve this, however this 
> solution works REALLY well and is not expensive. One last benefit 
> you’ll be able to use this to calibrate your PowerSDR setup, 
> guaranteeing absolute frequency accuracy :)
>
> Good luck
>
> Kevin - M0KHZ
>
> On 27 Oct 2009, at 10:17, Jeff Cook wrote:
>
>> 230392673042
>




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