Empathy List Archives

JH

Jerry Hancock

Mon, May 8, 2017 12:52 AM

I was showing my son how we could measure the difference in cable lengths by using the velocity of light and cable velocity factor. I used a scope to measure the offset and was then thinking the 5335 could do it more accurately, but I was wrong, as it only reports to the nanosecond. I thought I had seen somewhere where people were getting higher resolution using software along with the 5335, no?

Thanks

I was showing my son how we could measure the difference in cable lengths by using the velocity of light and cable velocity factor. I used a scope to measure the offset and was then thinking the 5335 could do it more accurately, but I was wrong, as it only reports to the nanosecond. I thought I had seen somewhere where people were getting higher resolution using software along with the 5335, no? Thanks

BK

Bob kb8tq

Mon, May 8, 2017 2:05 AM

Hi

The 53131 and 53132 will get you more resolution. The TICC, the 5370, and the SR620 will do even better. None
of them will do as well as a really fast scope.

Bob

On May 7, 2017, at 8:52 PM, Jerry Hancock jerry@hanler.com wrote:

I was showing my son how we could measure the difference in cable lengths by using the velocity of light and cable velocity factor. I used a scope to measure the offset and was then thinking the 5335 could do it more accurately, but I was wrong, as it only reports to the nanosecond. I thought I had seen somewhere where people were getting higher resolution using software along with the 5335, no?

Thanks

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Hi The 53131 and 53132 will get you more resolution. The TICC, the 5370, and the SR620 will do even better. None of them will do as well as a really fast scope. Bob > On May 7, 2017, at 8:52 PM, Jerry Hancock <jerry@hanler.com> wrote: > > I was showing my son how we could measure the difference in cable lengths by using the velocity of light and cable velocity factor. I used a scope to measure the offset and was then thinking the 5335 could do it more accurately, but I was wrong, as it only reports to the nanosecond. I thought I had seen somewhere where people were getting higher resolution using software along with the 5335, no? > > Thanks > _______________________________________________ > 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.

D

David

Mon, May 8, 2017 3:47 AM

My Racal-Dana 1992 is the same way; its time interval mode is limited
to the 1 nanosecond interpolated resolution of the counter.

Some counters support time interval averaging which will produce much
much higher resolution but often they have a minimum time interval.

If the transmission line to be measured is configured as a shorted
line, then the pulse width can be measured instead to determine the
line length and pulse width averaging is much more commonly supported.

On Sun, 7 May 2017 22:05:58 -0400, you wrote:

Hi

The 53131 and 53132 will get you more resolution. The TICC, the 5370, and the SR620 will do even better. None
of them will do as well as a really fast scope.

Bob

On May 7, 2017, at 8:52 PM, Jerry Hancock jerry@hanler.com wrote:

I was showing my son how we could measure the difference in cable lengths by using the velocity of light and cable velocity factor. I used a scope to measure the offset and was then thinking the 5335 could do it more accurately, but I was wrong, as it only reports to the nanosecond. I thought I had seen somewhere where people were getting higher resolution using software along with the 5335, no?

My Racal-Dana 1992 is the same way; its time interval mode is limited to the 1 nanosecond interpolated resolution of the counter. Some counters support time interval averaging which will produce much much higher resolution but often they have a minimum time interval. If the transmission line to be measured is configured as a shorted line, then the pulse width can be measured instead to determine the line length and pulse width averaging is much more commonly supported. On Sun, 7 May 2017 22:05:58 -0400, you wrote: >Hi > >The 53131 and 53132 will get you more resolution. The TICC, the 5370, and the SR620 will do even better. None >of them will do as well as a really fast scope. > >Bob > >> On May 7, 2017, at 8:52 PM, Jerry Hancock <jerry@hanler.com> wrote: >> >> I was showing my son how we could measure the difference in cable lengths by using the velocity of light and cable velocity factor. I used a scope to measure the offset and was then thinking the 5335 could do it more accurately, but I was wrong, as it only reports to the nanosecond. I thought I had seen somewhere where people were getting higher resolution using software along with the 5335, no?

TS

Tim Shoppa

Mon, May 8, 2017 1:03 PM

Jerry, it's very different than the equipment you currently have, but there
are specialized microwave TDR's that are used to quantify and localize
impedance bumps down to the fractional inch level (which would be tens of
picoseconds). You can "see" every connector and PCB/cable transition using
these TDR's.

Tim N3QE

On Sun, May 7, 2017 at 8:52 PM, Jerry Hancock jerry@hanler.com wrote:

I was showing my son how we could measure the difference in cable lengths
by using the velocity of light and cable velocity factor. I used a scope
to measure the offset and was then thinking the 5335 could do it more
accurately, but I was wrong, as it only reports to the nanosecond. I
thought I had seen somewhere where people were getting higher resolution
using software along with the 5335, no?

Thanks

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.

Jerry, it's very different than the equipment you currently have, but there are specialized microwave TDR's that are used to quantify and localize impedance bumps down to the fractional inch level (which would be tens of picoseconds). You can "see" every connector and PCB/cable transition using these TDR's. Tim N3QE On Sun, May 7, 2017 at 8:52 PM, Jerry Hancock <jerry@hanler.com> wrote: > I was showing my son how we could measure the difference in cable lengths > by using the velocity of light and cable velocity factor. I used a scope > to measure the offset and was then thinking the 5335 could do it more > accurately, but I was wrong, as it only reports to the nanosecond. I > thought I had seen somewhere where people were getting higher resolution > using software along with the 5335, no? > > Thanks > _______________________________________________ > 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. >

JH

Jerry Hancock

Mon, May 8, 2017 5:09 PM

Tim, I understand all about TDRs, was doing communications cable tests going back to '76 at IBM. This was a simple experiment to show my son (who is thinking of becoming an engineer) how precise certain equipment is.

On May 8, 2017, at 6:03 AM, Tim Shoppa tshoppa@gmail.com wrote:

Jerry, it's very different than the equipment you currently have, but there
are specialized microwave TDR's that are used to quantify and localize
impedance bumps down to the fractional inch level (which would be tens of
picoseconds). You can "see" every connector and PCB/cable transition using
these TDR's.

Tim N3QE

Tim, I understand all about TDRs, was doing communications cable tests going back to '76 at IBM. This was a simple experiment to show my son (who is thinking of becoming an engineer) how precise certain equipment is. > On May 8, 2017, at 6:03 AM, Tim Shoppa <tshoppa@gmail.com> wrote: > > Jerry, it's very different than the equipment you currently have, but there > are specialized microwave TDR's that are used to quantify and localize > impedance bumps down to the fractional inch level (which would be tens of > picoseconds). You can "see" every connector and PCB/cable transition using > these TDR's. > > Tim N3QE >

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Using 5335 frequency counter for timing