[time-nuts] Thunderbolt & Lady Heather 48 hour precision survey

[WarrenS]

Black means NO data available
This can be due to several possible reasons,

1) the elevation mask setting, Tbolt does not report on anything below the 
mask setting.
2) Run is not long enough.  Have not yet had a bird in that position yet.
3) no satellites ever in that position, like North when in the northern 
hemisphere.
4) obstructions from things

I thing what you are asking about, the answer is mostly 3 or 1

The mask was set to 20 because of multipath and weak signals below 20 
degrees
One sign of Multipath is high ripple in the signal strength, best seen using 
Tbolts "SAD Z"  command

ws

***********************

[time-nuts] Thunderbolt & Lady Heather 48 hour precision survey
J. L. Trantham jltran at att.net
Sat Nov 27 17:28:23 UTC 2010

Warren,

Just curious.  Does the 'black' background of your image resemble the
horizon at your location?  Trees, buildings, towers, etc.?

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] 
On
Behalf Of WarrenS
Sent: Saturday, November 27, 2010 11:15 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Thunderbolt & Lady Heather 48 hour precision survey



Right, For best performance, in fix mode operation, for a Tbolt, you don't
want to run at zero (or 5) degrees.
This is just one test in a series of necessary test, if one wants to improve

their Tbolt to better than the Default settings.
The zero degree mask is a temporary setting so that the Tbolt can do a full
antenna signal strength vs. position survey using Tbolts's "SAS" command.
The purpose of which is to find the BEST elevation setting, which turns out
to be more like 15 to 35 deg for the typical Tbolt setups I've seen.
Attached is a limited survey where the finial cutoff was set at 20 degrees.
The cut off was set there because the full survey showed that in this case
"BAD" things where starting to happen around 20 degrees

ws