Maybe something too basic many too say, but did you lower the Tbolts "signal level mask AMU" setting? Default is 3, set to 1 or 2 so that it will accept lower level signals
----- Original Message ----- From: <[email protected]> To: <[email protected]> Sent: Saturday, November 21, 2009 11:40 AM Subject: [time-nuts] Thunderbolt reception problems > Hi guys, > > some weeks ago we talked about reception problems on Trimble Thunderbolt > units. I finally took the time to download the Trimble monitor again, and get > my unit locked again. Here is what I found: > > The unit was running continuously for the last months, but wasn't locked. > Using the Trimble monitor, I restarted the unit, now connected directly to > my antenna, then after the survey was done let it run from my antenna > splitter. > > This works, but just barely. I use an Agilent 58512A amp, followed by a > Mini Circuits ZB4PD1-152-75+ 1-to-4 passive splitter. > > In the attached plot a JLT FireFly-IIA and the Thunderbolt are both running > from the same Mini Circuits splitter. The Antenna sense circuit in the > Thunderbolt is happy, but the signal strength is just at the threshold of > working. The Sats kick in and out. Please see the attached screen shot. > > At the same time the FireFly-IIA receiver is tracking 11 Sats with perfect > signal strengths (up to 45dB+ C/No), from the same feed. > > The difference in receiver performance is quite clear. Unfortunately I > have only a single antenna, so need to run the Thunderbolt from a splitter. > > One can also see two more interesting tid-bits in the screen shot: the > FireFly-IIA is tracking and using WAAS Sat PRN 48 (PRN 51 goes in and out of > lo > ck due to a chimney being in the way), and it is showing true MSL rather > than just GPS Height. > > Thanks for the help, > bye, > Said > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
