[time-nuts] No GPS satellites

[Doug Ronald]

I want to thank everyone who jumped in to contribute on my issue, especially Mike who supplied a much needed manual for this instrument.

Well, one unit with the xtal oscillator, had the upconverter end of the downconverter/upconverter chain in the chassis which was easily bypassed. Once that was accomplished, it locked up fairly quickly, however the LCD display had many bad segments. The rubidium unit has a defective Trimble receiver as it never gets out of the "looking for satellites" mode even after hours of on time, but it has a pristine LCD display, so I swapped around parts, and now have a good working standard. The xtal unit draws about half the power that the rubidium unit draws, so that one shall be my standard since it's on 24/7.

It was rewarding to use the TrueTime 10 MHz output for the reference input to my HP-5370B, and the frequency input of the counter connected to the Lucent 15 MHz standard. Both standards are completely independent right up to the antennas, and the counter shows only a few milliHertz variation.

Thanks again,
-Doug, W6DSR

-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Mike Cook
Sent: Thursday, February 26, 2015 4:13 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] No GPS satellites
Importance: Low

The XL-DC Can use either a normal L1 or Down converter Antenna according to the manual. <http://www.prostudioconnection.net/1112/xl-dc-manual.pdf>

If your antenna works with the Lucent then it will be a normal one. Does your XL-DC have any option codes? 


"Ceux qui sont prêts à abandonner une liberté essentielle pour obtenir une petite et provisoire sécurité, ne méritent ni liberté ni sécurité."
Benjimin Franklin

> Le 25 févr. 2015 à 20:35, Doug Ronald <doug at dougronald.com> a écrit :
> 
> I'm hoping someone can shed some light on my problem receiving any GPS satellites.
> 
> I have two TrueTime GPS Time & Frequency Receivers, Model XL-DC. One has a regular crystal oscillator, and the other one has a rubidium oscillator. I have two outdoor GPS antennas with internal LNAs, one a 28 dB gain unit, and the other a 40 dB unit. When either antenna is connected to my Lucent KS-24361, it locks right up and tracks up to 8 satellites. When either of the antennas is connected to the XL-DCs, they just sit there and status : "Looking for GPS satellites".
> 
> In the Alarm menu of either XL-DC there is an alarm for Antenna. Both units say "OK" and if I disconnect the antenna they both logically say "Open". So, what is the problem? I can't believe I don't have enough signal, after the Lucent locks-up right away. Is it possible the TrueTime sanctioned antenna has a down converter in it, perhaps placing the GPS signal from L-band to some lower frequency? I would appreciate any info the group might have...
> 
> -Doug Ronald
> W6DSR
> 
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