Empathy List Archives

JA

John Ackermann N8UR

Mon, Feb 4, 2008 1:18 AM

Has anyone here done any performance measurements of the Lucent RFTG-XO
unit? I am testing one now and getting extremely unimpressive results,
and wonder if anyone else has looked closely at these things.

What I'm seeing is almost flat ADEV in the low to mid 10s from 1 second
out to 40,000 seconds. At 100,000 seconds, it drops to the high 11s.*
To this point I haven't seen anything that looks like the normal GPSDO
characteristic of a rapid ADEV improvement from around 1000 seconds or
so. In fact, this is about the flattest ADEV plot I've ever seen from
an oscillator.

The frequency difference plot** shows a bang-bang effect of about
1.6x10e-9 over the course of a few minutes. This seems to go on
continuously (at least over the 4 days of data so far). That certainly
explains the mediocre ADEV performance.

The thing does appear to be locked to GPS, but if my unit is working
properly, it's about the worst performing GPSDO I've seen.

By the way -- to do this test, I started with both the -XO and -RB units
online and interconnected the way they were supposed to be. After a
couple of days of operation, I pulled the interconnect cable and the -RB
went off line, while the -XO came on. I then started data collection.
After I'm satisfied with the amount of XO data I have, I'll reconnect
the cable and do the same test on the -RB side. The full set of plots
is at http://www.febo.com/pages/oscillators/rftg/ and will be updated as
I get more data.

John

http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-adevplot.png
** http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-freqdiff.png

Has anyone here done any performance measurements of the Lucent RFTG-XO unit? I am testing one now and getting extremely unimpressive results, and wonder if anyone else has looked closely at these things. What I'm seeing is almost flat ADEV in the low to mid 10s from 1 second out to 40,000 seconds. At 100,000 seconds, it drops to the high 11s.* To this point I haven't seen anything that looks like the normal GPSDO characteristic of a rapid ADEV improvement from around 1000 seconds or so. In fact, this is about the flattest ADEV plot I've ever seen from an oscillator. The frequency difference plot** shows a bang-bang effect of about 1.6x10e-9 over the course of a few minutes. This seems to go on continuously (at least over the 4 days of data so far). That certainly explains the mediocre ADEV performance. The thing does appear to be locked to GPS, but if my unit is working properly, it's about the worst performing GPSDO I've seen. By the way -- to do this test, I started with both the -XO and -RB units online and interconnected the way they were supposed to be. After a couple of days of operation, I pulled the interconnect cable and the -RB went off line, while the -XO came on. I then started data collection. After I'm satisfied with the amount of XO data I have, I'll reconnect the cable and do the same test on the -RB side. The full set of plots is at http://www.febo.com/pages/oscillators/rftg/ and will be updated as I get more data. John * http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-adevplot.png ** http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-freqdiff.png

TV

Tom Van Baak

Mon, Feb 4, 2008 3:32 AM

Has anyone here done any performance measurements of the Lucent RFTG-XO
unit? I am testing one now and getting extremely unimpressive results,
and wonder if anyone else has looked closely at these things.

Unlocked, this is what I got for the RFTG (Rb):
http://www.leapsecond.com/museum/lucent-rftg-rb/

How does that compare with yours, unlocked?

/tvb

> Has anyone here done any performance measurements of the Lucent RFTG-XO > unit? I am testing one now and getting extremely unimpressive results, > and wonder if anyone else has looked closely at these things. Unlocked, this is what I got for the RFTG (Rb): http://www.leapsecond.com/museum/lucent-rftg-rb/ How does that compare with yours, unlocked? /tvb

DI

David I. Emery

Mon, Feb 4, 2008 4:38 AM

On Sun, Feb 03, 2008 at 08:18:07PM -0500, John Ackermann N8UR wrote:

Has anyone here done any performance measurements of the Lucent RFTG-XO
unit? I am testing one now and getting extremely unimpressive results,
and wonder if anyone else has looked closely at these things.

By the way -- to do this test, I started with both the -XO and -RB units
online and interconnected the way they were supposed to be. After a
couple of days of operation, I pulled the interconnect cable and the -RB
went off line, while the -XO came on. I then started data collection.
After I'm satisfied with the amount of XO data I have, I'll reconnect
the cable and do the same test on the -RB side. The full set of plots
is at http://www.febo.com/pages/oscillators/rftg/ and will be updated as
I get more data.

What versions of the units is this for and with what firmware - that

is awful !!!

--
Dave Emery N1PRE/AE, die@dieconsulting.com DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in
celebration of what could have been, but wasn't and is not to be now either."

On Sun, Feb 03, 2008 at 08:18:07PM -0500, John Ackermann N8UR wrote: > Has anyone here done any performance measurements of the Lucent RFTG-XO > unit? I am testing one now and getting extremely unimpressive results, > and wonder if anyone else has looked closely at these things. > > By the way -- to do this test, I started with both the -XO and -RB units > online and interconnected the way they were supposed to be. After a > couple of days of operation, I pulled the interconnect cable and the -RB > went off line, while the -XO came on. I then started data collection. > After I'm satisfied with the amount of XO data I have, I'll reconnect > the cable and do the same test on the -RB side. The full set of plots > is at http://www.febo.com/pages/oscillators/rftg/ and will be updated as > I get more data. What versions of the units is this for and with what firmware - that is awful !!! -- Dave Emery N1PRE/AE, die@dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either."

BH

Bill Hawkins

Thu, Nov 6, 2008 5:48 AM

John,

Back in February, you looked at the Lucent GPSDO and declared it the
worst you'd seen.

Did you ever update that opinion? Is the complete set for $400 not worth
buying if you
have a pair of Z3801s that perform some heroic jumps? This is just a
hobby, not long
baseline interferometry.

Bill Hawkins

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of John Ackermann N8UR
Sent: Sunday, February 03, 2008 7:18 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Lucent RFTG-XO performance...

Has anyone here done any performance measurements of the Lucent RFTG-XO
unit? I am testing one now and getting extremely unimpressive results,
and wonder if anyone else has looked closely at these things.

What I'm seeing is almost flat ADEV in the low to mid 10s from 1 second
out to 40,000 seconds. At 100,000 seconds, it drops to the high 11s.*
To this point I haven't seen anything that looks like the normal GPSDO
characteristic of a rapid ADEV improvement from around 1000 seconds or
so. In fact, this is about the flattest ADEV plot I've ever seen from
an oscillator.

The frequency difference plot** shows a bang-bang effect of about
1.6x10e-9 over the course of a few minutes. This seems to go on
continuously (at least over the 4 days of data so far). That certainly
explains the mediocre ADEV performance.

The thing does appear to be locked to GPS, but if my unit is working
properly, it's about the worst performing GPSDO I've seen.

By the way -- to do this test, I started with both the -XO and -RB units
online and interconnected the way they were supposed to be. After a
couple of days of operation, I pulled the interconnect cable and the -RB
went off line, while the -XO came on. I then started data collection.
After I'm satisfied with the amount of XO data I have, I'll reconnect
the cable and do the same test on the -RB side. The full set of plots
is at http://www.febo.com/pages/oscillators/rftg/ and will be updated as
I get more data.

John

http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-adevplot.png
** http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-freqdiff.png

time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

John, Back in February, you looked at the Lucent GPSDO and declared it the worst you'd seen. Did you ever update that opinion? Is the complete set for $400 not worth buying if you have a pair of Z3801s that perform some heroic jumps? This is just a hobby, not long baseline interferometry. Bill Hawkins -----Original Message----- From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On Behalf Of John Ackermann N8UR Sent: Sunday, February 03, 2008 7:18 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Lucent RFTG-XO performance... Has anyone here done any performance measurements of the Lucent RFTG-XO unit? I am testing one now and getting extremely unimpressive results, and wonder if anyone else has looked closely at these things. What I'm seeing is almost flat ADEV in the low to mid 10s from 1 second out to 40,000 seconds. At 100,000 seconds, it drops to the high 11s.* To this point I haven't seen anything that looks like the normal GPSDO characteristic of a rapid ADEV improvement from around 1000 seconds or so. In fact, this is about the flattest ADEV plot I've ever seen from an oscillator. The frequency difference plot** shows a bang-bang effect of about 1.6x10e-9 over the course of a few minutes. This seems to go on continuously (at least over the 4 days of data so far). That certainly explains the mediocre ADEV performance. The thing does appear to be locked to GPS, but if my unit is working properly, it's about the worst performing GPSDO I've seen. By the way -- to do this test, I started with both the -XO and -RB units online and interconnected the way they were supposed to be. After a couple of days of operation, I pulled the interconnect cable and the -RB went off line, while the -XO came on. I then started data collection. After I'm satisfied with the amount of XO data I have, I'll reconnect the cable and do the same test on the -RB side. The full set of plots is at http://www.febo.com/pages/oscillators/rftg/ and will be updated as I get more data. John * http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-adevplot.png ** http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-freqdiff.png _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.

JA

John Ackermann N8UR

Thu, Nov 6, 2008 1:12 PM

Hi Bill --

I haven't done any more testing, but I'm pretty convinced that there is
something wrong with my hardware, though the monitoring software didn't
indicate any obvious problems. I need to go back and revisit, but due
to a bunch of health problems earlier this year (now just about over
with), I haven't gotten very much done in the basement for a while.

John

Bill Hawkins wrote:

John,

Back in February, you looked at the Lucent GPSDO and declared it the
worst you'd seen.

Did you ever update that opinion? Is the complete set for $400 not worth
buying if you
have a pair of Z3801s that perform some heroic jumps? This is just a
hobby, not long
baseline interferometry.

Bill Hawkins

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of John Ackermann N8UR
Sent: Sunday, February 03, 2008 7:18 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Lucent RFTG-XO performance...

Has anyone here done any performance measurements of the Lucent RFTG-XO
unit? I am testing one now and getting extremely unimpressive results,
and wonder if anyone else has looked closely at these things.

What I'm seeing is almost flat ADEV in the low to mid 10s from 1 second
out to 40,000 seconds. At 100,000 seconds, it drops to the high 11s.*
To this point I haven't seen anything that looks like the normal GPSDO
characteristic of a rapid ADEV improvement from around 1000 seconds or
so. In fact, this is about the flattest ADEV plot I've ever seen from
an oscillator.

The frequency difference plot** shows a bang-bang effect of about
1.6x10e-9 over the course of a few minutes. This seems to go on
continuously (at least over the 4 days of data so far). That certainly
explains the mediocre ADEV performance.

The thing does appear to be locked to GPS, but if my unit is working
properly, it's about the worst performing GPSDO I've seen.

By the way -- to do this test, I started with both the -XO and -RB units
online and interconnected the way they were supposed to be. After a
couple of days of operation, I pulled the interconnect cable and the -RB
went off line, while the -XO came on. I then started data collection.
After I'm satisfied with the amount of XO data I have, I'll reconnect
the cable and do the same test on the -RB side. The full set of plots
is at http://www.febo.com/pages/oscillators/rftg/ and will be updated as
I get more data.

John

http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-adevplot.png
** http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-freqdiff.png

time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Hi Bill -- I haven't done any more testing, but I'm pretty convinced that there is something wrong with my hardware, though the monitoring software didn't indicate any obvious problems. I need to go back and revisit, but due to a bunch of health problems earlier this year (now just about over with), I haven't gotten very much done in the basement for a while. John ---- Bill Hawkins wrote: > John, > > Back in February, you looked at the Lucent GPSDO and declared it the > worst you'd seen. > > Did you ever update that opinion? Is the complete set for $400 not worth > buying if you > have a pair of Z3801s that perform some heroic jumps? This is just a > hobby, not long > baseline interferometry. > > Bill Hawkins > > > -----Original Message----- > From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On > Behalf Of John Ackermann N8UR > Sent: Sunday, February 03, 2008 7:18 PM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] Lucent RFTG-XO performance... > > Has anyone here done any performance measurements of the Lucent RFTG-XO > unit? I am testing one now and getting extremely unimpressive results, > and wonder if anyone else has looked closely at these things. > > What I'm seeing is almost flat ADEV in the low to mid 10s from 1 second > out to 40,000 seconds. At 100,000 seconds, it drops to the high 11s.* > To this point I haven't seen anything that looks like the normal GPSDO > characteristic of a rapid ADEV improvement from around 1000 seconds or > so. In fact, this is about the flattest ADEV plot I've ever seen from > an oscillator. > > The frequency difference plot** shows a bang-bang effect of about > 1.6x10e-9 over the course of a few minutes. This seems to go on > continuously (at least over the 4 days of data so far). That certainly > explains the mediocre ADEV performance. > > The thing does appear to be locked to GPS, but if my unit is working > properly, it's about the worst performing GPSDO I've seen. > > By the way -- to do this test, I started with both the -XO and -RB units > online and interconnected the way they were supposed to be. After a > couple of days of operation, I pulled the interconnect cable and the -RB > went off line, while the -XO came on. I then started data collection. > After I'm satisfied with the amount of XO data I have, I'll reconnect > the cable and do the same test on the -RB side. The full set of plots > is at http://www.febo.com/pages/oscillators/rftg/ and will be updated as > I get more data. > > John > > * http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-adevplot.png > ** http://www.febo.com/pages/oscillators/rftg/rftg-xo_cs1-freqdiff.png > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there.

time-nuts@lists.febo.com

Lucent RFTG-XO performance...

John