<html><body>Phil,<br><br>I may have missed a message somewhere<br>But isn't GIBRALTAR supposed to address all of these issues..<br>And provide a GPS disciplined standard for use with or without the rest of the HPSDR?<br><br>Peter Hughes<br>N7BMG<br><br>
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-------- Original Message --------<br>
Subject: Re: [hpsdr] GPS Receiver<br>
From: Graham Haddock <KE9H@austin.rr.com><br>
Date: Tue, December 18, 2007 10:34 am<br>
To: Phil Harman <phil@pharman.org><br>
Cc: HPSDR Reflector <hpsdr@hpsdr.org><br>
<br>
***** High Performance Software Defined Radio Discussion List *****<br>
<br>
Phil:<br>
<br>
Not my area of expertise at all, but....<br>
<br>
1 us. accuracy? jitter? offset? on the Garmin seems to be poor, if you<br>
are going to try to to discipline a frequency standard to 10E-9 to 10E-11.<br>
<br>
I would expect the native timing accuracy inside of a GPS receiver is<br>
better than 0.1 us on just GPS, and 0.01us with WAAS active.<br>
<br>
The question becomes... how did they bring it out? Through software?<br>
That is, have the on board processor transfer the data internally to<br>
an output port? If so, sounds like the potential for a lot of jitter<br>
on the pulse.<br>
<br>
The only GPS receiver that I can find, that is in current production, <br>
with a timing pulse<br>
pedigree is the Motorola Oncore, currently evolved to the M12M (no WAAS).<br>
<br>
I was about to order one of the M12M Timing Starter Kits from Synergy-GPS<br>
(US$198.)<br>
<br>
If you want me to order an additional one for you, please let<br>
me know.<br>
<br>
What doe the rest of your 10 MHz frequency time base look like?<br>
<br>
--- Graham<br>
<br>
==<br>
<br>
Phil Harman wrote:<br>
> ***** High Performance Software Defined Radio Discussion List *****<br>
><br>
><br>
> I'm looking for a GPS receiver with a 1pps output suitable as a source <br>
> for my 10MHz GPS locked reference. I came across this new Garmin <br>
> receiver - looks very nice physically but not sure if the 1pps spec at <br>
> ~1uS is satisfactory.<br>
><br>
> The device is a GPS 18 and the spec is here<br>
><br>
> <<a href="http://www8.garmin.com/manuals/425_TechnicalSpecification.pdf" target="_blank">http://www8.garmin.com/manuals/425_TechnicalSpecification.pdf</a>><br>
><br>
> Anyone have any experience or comments on its suitability please.<br>
><br>
> 73's Phil...VK6APH<br>
><br>
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