Re: [time-nuts] Another ThunderBolt cabling question
Acrually the PPS output has very low impedance, so you can probably load it with 5 instruments, each with 50 termination. Not so for the 10MHz though Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: David C. Partridge david.partri...@perdrix.co.uk Sender: time-nuts-boun...@febo.com Date: Thu, 14 Jun 2012 01:59:42 To: 'Chris Wilson'ch...@chriswilson.tv; 'Discussion of precise time and frequency measurement'time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Another ThunderBolt cabling question No you can't load the 10MHz (or the PPS) with five instruments in parallel. You need a distribution amplifier. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Wilson Sent: 13 June 2012 22:33 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Another ThunderBolt cabling question 13/06/2012 22:27 About to do the permanent installation, if I bring two leads from the 10 MHz and 1 PPS BNC sockets on the TB to a panel in my shck can i have say 5 BNC sockets on the panel wired in parallel, with the lead from the 10 MHz socket on the TB feeding them all? And a single socket for the 1 PPS? Any need to screen the back of the socket panel, or enclose it in a metal box? Cheers. Oh, I have been running lady Heather for a while tonight, here's a screen capture, does it look OK, ther's suddenly just two traces appeared? Thanks. http://www.chriswilson.tv/heather.png -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ 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 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.
Re: [time-nuts] Another ThunderBolt cabling question
On Thu, Jun 14, 2012 at 3:59 AM, shali...@gmail.com wrote: Acrually the PPS output has very low impedance, so you can probably load it with 5 instruments, each with 50 termination. My problem with PPS distribution was the fast raise time got smeared by the long cable. Lots of guesses about why. Could be reflections off the end, capacitance in the cable. The problem is that I want WAY under 1 microsecond level performance out of a PPS signal. The trouble is that the PPS is a single ended signal and the leading edge is defined by some voltage threshold. So it is sensitive to noise. Two solutions I found (1) differential transmitters and receivers at each end, like RS-422 type work, or (2) simply move the thunderbolt physicaly close and use an 18 inch cable. Take my word for it, the T-Bolt is not able to drive a 100 foot long twisted pair cable Not so for the 10MHz though Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: David C. Partridge david.partri...@perdrix.co.uk Sender: time-nuts-boun...@febo.com Date: Thu, 14 Jun 2012 01:59:42 To: 'Chris Wilson'ch...@chriswilson.tv; 'Discussion of precise time and frequency measurement'time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Another ThunderBolt cabling question No you can't load the 10MHz (or the PPS) with five instruments in parallel. You need a distribution amplifier. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Wilson Sent: 13 June 2012 22:33 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Another ThunderBolt cabling question 13/06/2012 22:27 About to do the permanent installation, if I bring two leads from the 10 MHz and 1 PPS BNC sockets on the TB to a panel in my shck can i have say 5 BNC sockets on the panel wired in parallel, with the lead from the 10 MHz socket on the TB feeding them all? And a single socket for the 1 PPS? Any need to screen the back of the socket panel, or enclose it in a metal box? Cheers. Oh, I have been running lady Heather for a while tonight, here's a screen capture, does it look OK, ther's suddenly just two traces appeared? Thanks. http://www.chriswilson.tv/heather.png -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ 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 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. -- Chris Albertson Redondo Beach, California ___ 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.
Re: [time-nuts] Another ThunderBolt cabling question
Yes, highly recommended the differential line approach. On Thu, Jun 14, 2012 at 6:38 PM, Chris Albertson albertson.ch...@gmail.comwrote: On Thu, Jun 14, 2012 at 3:59 AM, shali...@gmail.com wrote: Acrually the PPS output has very low impedance, so you can probably load it with 5 instruments, each with 50 termination. My problem with PPS distribution was the fast raise time got smeared by the long cable. Lots of guesses about why. Could be reflections off the end, capacitance in the cable. The problem is that I want WAY under 1 microsecond level performance out of a PPS signal. The trouble is that the PPS is a single ended signal and the leading edge is defined by some voltage threshold. So it is sensitive to noise. Two solutions I found (1) differential transmitters and receivers at each end, like RS-422 type work, or (2) simply move the thunderbolt physicaly close and use an 18 inch cable. Take my word for it, the T-Bolt is not able to drive a 100 foot long twisted pair cable Not so for the 10MHz though Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: David C. Partridge david.partri...@perdrix.co.uk Sender: time-nuts-boun...@febo.com Date: Thu, 14 Jun 2012 01:59:42 To: 'Chris Wilson'ch...@chriswilson.tv; 'Discussion of precise time and frequency measurement'time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Another ThunderBolt cabling question No you can't load the 10MHz (or the PPS) with five instruments in parallel. You need a distribution amplifier. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Wilson Sent: 13 June 2012 22:33 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Another ThunderBolt cabling question 13/06/2012 22:27 About to do the permanent installation, if I bring two leads from the 10 MHz and 1 PPS BNC sockets on the TB to a panel in my shck can i have say 5 BNC sockets on the panel wired in parallel, with the lead from the 10 MHz socket on the TB feeding them all? And a single socket for the 1 PPS? Any need to screen the back of the socket panel, or enclose it in a metal box? Cheers. Oh, I have been running lady Heather for a while tonight, here's a screen capture, does it look OK, ther's suddenly just two traces appeared? Thanks. http://www.chriswilson.tv/heather.png -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ 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 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. -- Chris Albertson Redondo Beach, California ___ 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] Another ThunderBolt cabling question
13/06/2012 22:27 About to do the permanent installation, if I bring two leads from the 10 MHz and 1 PPS BNC sockets on the TB to a panel in my shck can i have say 5 BNC sockets on the panel wired in parallel, with the lead from the 10 MHz socket on the TB feeding them all? And a single socket for the 1 PPS? Any need to screen the back of the socket panel, or enclose it in a metal box? Cheers. Oh, I have been running lady Heather for a while tonight, here's a screen capture, does it look OK, ther's suddenly just two traces appeared? Thanks. http://www.chriswilson.tv/heather.png -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ 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.
Re: [time-nuts] Another ThunderBolt cabling question
Sure enough the Thunderbolt will be able to drive five BNC jacks just fine. When you get into problems is when you try and plug stuff into the sockets. Kidding aside, really what you plug into hit is what matters. Three is easy, five is kind of pushing it without a distribution amp. All depends on what you are plugging in. For driving multiple piece of test equipment the conventional way is to use a few T to connecter and daisy chain the cable then at the end connect a 50 ohm terminator. I think this setup gets a better signal without so many reflections In the real world your plan would work fine. Most test equipment has well engineered 10MHz input and can work on anything you give it. But in this case it is cheap and easy to simply use some TEEs. On Wed, Jun 13, 2012 at 2:33 PM, Chris Wilson ch...@chriswilson.tv wrote: 13/06/2012 22:27 About to do the permanent installation, if I bring two leads from the 10 MHz and 1 PPS BNC sockets on the TB to a panel in my shck can i have say 5 BNC sockets on the panel wired in parallel, with the lead from the 10 MHz socket on the TB feeding them all? And a single socket for the 1 PPS? Any need to screen the back of the socket panel, or enclose it in a metal box? Cheers. Oh, I have been running lady Heather for a while tonight, here's a screen capture, does it look OK, ther's suddenly just two traces appeared? Thanks. http://www.chriswilson.tv/heather.png -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ 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. -- Chris Albertson Redondo Beach, California ___ 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] Another ThunderBolt cabling question
You probably should not drive several devices in parallel from one output. They may have fixed 50 ohm terminators. If not, it is best to daisy the cable from one device to the next and terminate the end device with 50 ohms. Also, that version of Lady Heather is very old. You should get the V 3.0 beta from the KE5FX web site. ___ 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.
Re: [time-nuts] Another ThunderBolt cabling question
No you can't load the 10MHz (or the PPS) with five instruments in parallel. You need a distribution amplifier. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Wilson Sent: 13 June 2012 22:33 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Another ThunderBolt cabling question 13/06/2012 22:27 About to do the permanent installation, if I bring two leads from the 10 MHz and 1 PPS BNC sockets on the TB to a panel in my shck can i have say 5 BNC sockets on the panel wired in parallel, with the lead from the 10 MHz socket on the TB feeding them all? And a single socket for the 1 PPS? Any need to screen the back of the socket panel, or enclose it in a metal box? Cheers. Oh, I have been running lady Heather for a while tonight, here's a screen capture, does it look OK, ther's suddenly just two traces appeared? Thanks. http://www.chriswilson.tv/heather.png -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ 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.
Re: [time-nuts] Another ThunderBolt cabling question
Hi That all looks very normal. LH can scale the graph on it's own. I *know* that's true because it couldn't have been my typing on the keyboard that did it. That's my story and I'm sticking to it :)…… Your DAC voltage looks good and the oscillator seems to be settling well. I'd say you are running ok. I'd run coax for both the 1 pps and the 10 MHz. One pps jack should be plenty for now. If you run multiple jacks for the 10 MHz, rig up a simple resistive splitter. Bob On Jun 13, 2012, at 5:33 PM, Chris Wilson wrote: 13/06/2012 22:27 About to do the permanent installation, if I bring two leads from the 10 MHz and 1 PPS BNC sockets on the TB to a panel in my shck can i have say 5 BNC sockets on the panel wired in parallel, with the lead from the 10 MHz socket on the TB feeding them all? And a single socket for the 1 PPS? Any need to screen the back of the socket panel, or enclose it in a metal box? Cheers. Oh, I have been running lady Heather for a while tonight, here's a screen capture, does it look OK, ther's suddenly just two traces appeared? Thanks. http://www.chriswilson.tv/heather.png -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ 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.
