Re: opensource_gps Digest, Vol 65, Issue 1

Hello Siddharth,

Most likely the shortened coax cable is causing the front-end of the
receiver to be overloaded with too much gain.  The cable length that comes
with that Trimble antenna is such that it provides enough attenuation to
work properly with that receiver.

You may want to try adding some coax back to that antenna to introduce loss
in order to get the correct amount of gain.

Regards,

Doug Baker
GPS Creations, Inc.
PO Box 381272
Germantown, TN 38183-1272
USA
Cell Phone: 949-547-0608

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of
[email protected]
Sent: Saturday, February 05, 2011 2:00 PM
To: [email protected]
Subject: opensource_gps Digest, Vol 65, Issue 1

Send opensource_gps mailing list submissions to
	[email protected]

To subscribe or unsubscribe via the World Wide Web, visit
	http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/opensource_gps
or, via email, send a message with subject or body 'help' to
	[email protected]

You can reach the person managing the list at
	[email protected]

When replying, please edit your Subject line so it is more specific
than "Re: Contents of opensource_gps digest..."


Today's Topics:

   1. Antenna modification - False Acquisitions problem
      (Siddharth Paliwal)


----------------------------------------------------------------------

Message: 1
Date: Sat, 5 Feb 2011 12:35:05 +0530
From: Siddharth Paliwal <[email protected]>
Subject: [OpenSource_GPS] Antenna modification - False Acquisitions
	problem
To: [email protected]
Message-ID:
	<[email protected]>
Content-Type: text/plain; charset="iso-8859-1"

Hello,

I am running the GPL-GPS code on the GPS600 receiver that I purchased from
GPS Creations. I had to modify my Antenna(Trimble) cable length for some
reasons, so I got the cable shortened and got another connector re-crimped
to it. But this modified Antenna seems to have some problems. Now I am
unable to get lock on satellites, but there seem to be a large no. of False
Acquisitions, in the sense that most of the channels (out of 12 available)
now transition upto the Pull-in state and then fall back to Acquisition
state. And the code seems to be running perfectly fine with an unmodified
Trimble Antenna (tracking up to 6-7 satellites !!).
Is there any way to check if there are any problems with my modified Antenna
(probably Impedance matching problems?) besides running it on the GPS
receiver and checking If I'm able to lock satellites or not. And also what
are the possible places at which I might have gone wrong?
Any help would be highly appreciated.

Thanks.

-- 
Siddharth Paliwal
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.psas.pdx.edu/pipermail/opensource_gps/attachments/20110205/bdb
3e3ed/attachment.html>

------------------------------

_______________________________________________
opensource_gps mailing list
[email protected]
http://lists.psas.pdx.edu/cgi-bin/mailman/listinfo/opensource_gps


End of opensource_gps Digest, Vol 65, Issue 1
*********************************************