[time-nuts] Factors other Than Antenna Splitters (Bob Camp)

johncroos at aol.com johncroos at aol.com
Sat Oct 13 13:03:28 EDT 2012


Bob -

Thanks you for your comments below.

"As others have reported, a TBolt in a good environment is closer to a 
1 or 2
ns one sigma (over 100+ seconds) than to the numbers in the Trimble 
manual.

The satellite data on the NIST site shows much better numbers than they 
show
for Satellite Clock and Satellite orbit."

That is encouraging. Trimble probably worst cased it to avoid issues. 
Good idea for
a product.

On further thought it occurred to me that that for purposes of 
comparison
between receivers use of a single antenna reduces the number of 
variables. Thus the issue comes
down to the effect of the presence of the second receiver - assuming 
that a passive splitter in a
lab environment stays pretty well put. I think this can be proven by 
test easily enough.

One simple experiment for the curious would be to observe the 
performance of one receiver (the UUT)
with both connected to the splitter and then evaluate the change in 
performance with the second receiver under
the following conditions.

1. disconnected and cable open circuited
2  disconnected and cable terminated - may required a DC block
3. disconnected and cable shorted - may require DC block

Up until yesterday I had a setup for other tests that could do it 
easily, but I goofed and cleaned
up the bench.

best regards    - john k6iql





More information about the time-nuts mailing list