[time-nuts] Thunderbolt not seeing satellites

d.seiter at comcast.net d.seiter at comcast.net
Thu Jun 10 20:13:25 UTC 2010

Hi Steve, 

I don't know what the issue is, but my experience was very similar.  My Tbolt is the same (or very similar) to yours and worked fine for a few years off and on.  When Lady Heather became available, I took it out again.  It worked great with the antenna indoors in my lab for about 4 hours, then data displayed by LH gradually dropped off to what you would see if the unit wasn't working.  Since then I've tried again many times with the antenna in various locations, including full sky view with no results.  No alarms except for the ones you would see in a normal start situation.  Did the factory reset, etc.  It has never seen a sat since.  The antenna and cable are good. 

My primary receiver is a Z3801A, so I've had little incentive to delve into this problem (too many other pressing projects). 

----- Original Message ----- 
From: "Steve" <steve65 at suddenlink.net> 
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com> 
Sent: Thursday, June 10, 2010 12:09:11 PM GMT -08:00 US/Canada Pacific 
Subject: [time-nuts] Thunderbolt not seeing satellites 

Hi all, 

I have used a Trimble Thunderbolt for several years as a source for 
accurate 10MHz signals for counters and signal generators. I have 
occasionally looked at the Thunderbolt with a laptop and Lady Heather, 
but have largely treated the Thunderbolt as a 
plug-and-play-and-forget-about-it device. 

Several weeks ago I acquired one of the fluke.l monitors and attached it 
to the Thunderbolt, placing the fluke.l in a location such that I see it 
every time I walk into my shop. To my dismay, after watching the fluke.l 
for a while, I discovered that my Thunderbolt rarely sees satellites. I 
then began more intense monitoring with Lady Heather, finding that the 
Thunderbolt will on rare occasions show one satellite as usable, most of 
the time none. 

Another Thunderbolt, purchased in May, 2008, when they were sold on this 
list, routinely see 4-8 satellites when connected to the same antenna. 

Input voltage to the poor performing unit is about 28VDC. I did the 
tboltmon.exe Factory Reset with no discernible difference in 
performance. It is the Thunderbolt model in the aluminum housing with 
the red and black Trimble Thunderbolt label on top. 

Any thoughts as to what's wrong with it? 


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