[time-nuts] LPRO Rubidium schematics
LPRO time nuts, Is there a complete set of schematics available for the Efratom LPRO-101 Rubidium oscillator? I have the Repair reference guide by Fred de Vries, PE1FBO, Revision 6, 2010 which is very useful, but unfortunately it includes only some of the schematics. What I'm looking for is a schematic of the 20 MHz osc section and it's control loop. In an ongoing effort to initially see how good, and ultimately how simple, I can improve the performance of a LPRO based oscillator system, I've started with the basics by using a low noise 10811 as a clean up osc to improve the under 100 sec noise. To minimize any room temperature swings from effecting the performance, I've added an active temperature controller to keep the base plate heat sink temperature constant. To remove long term daily drift and get absolute freq accuracy, I'm using the C-field to discipline it to GPS. For that I'm using the LPRO as the external oscillator for a Tbolt and set the Tbolt's extended time constant at 12 to 24 hrs using Lady Heather. The results to date are very encouraging and show substantial improvement over the whole tau range from 0.01 sec out to days, in effect providing a low cost Cs substitute. ws ___ 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] LPRO Rubidium schematics
Warren Just how did you set up the tbolt to use the lpro as an external oscillator? I have both and would like to do the same. Thanks Rix Seacord K2AVP eseac...@verizon.net 845-628-0892 Home 914-262-9186 Cell On 6/1/2011 11:48 AM, WarrenS wrote: LPRO time nuts, Is there a complete set of schematics available for the Efratom LPRO-101 Rubidium oscillator? I have the Repair reference guide by Fred de Vries, PE1FBO, Revision 6, 2010 which is very useful, but unfortunately it includes only some of the schematics. What I'm looking for is a schematic of the 20 MHz osc section and it's control loop. In an ongoing effort to initially see how good, and ultimately how simple, I can improve the performance of a LPRO based oscillator system, I've started with the basics by using a low noise 10811 as a clean up osc to improve the under 100 sec noise. To minimize any room temperature swings from effecting the performance, I've added an active temperature controller to keep the base plate heat sink temperature constant. To remove long term daily drift and get absolute freq accuracy, I'm using the C-field to discipline it to GPS. For that I'm using the LPRO as the external oscillator for a Tbolt and set the Tbolt's extended time constant at 12 to 24 hrs using Lady Heather. The results to date are very encouraging and show substantial improvement over the whole tau range from 0.01 sec out to days, in effect providing a low cost Cs substitute. ws ___ 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] LPRO Rubidium schematics
Rix Just how did you set up the tbolt to use the lpro as an external oscillator? See John Miles site for notes of how to modify a Tbolt for use with an external Osc. http://www.ke5fx.com/tbolt.htm I just use the 10 MHz from the LPRO instead of the 10811 that he used see my post Tbolt disciplined LPRO Rubidium on May 13 2011 for how to set the Tbolt for extended TC http://www.febo.com/pipermail/time-nuts/2011-May/056526.html Attached is a 9 day LH test run where I was trying different Time constants etc. One of the important steps, Not show in that plot, is to check the loop recovery response by causing an intentional Freq or phase step error. If you have any trouble with it, let me know cause there may be typos in how I did it but it worked fine. ws ** [time-nuts] LPRO Rubidium schematics Rix Seacord eseacord at verizon.net Warren Just how did you set up the tbolt to use the lpro as an external oscillator? I have both and would like to do the same. Thanks Rix Seacord K2AVP eseacord at verizon.net 845-628-0892 Home 914-262-9186 Cell *** On 6/1/2011 11:48 AM, WarrenS wrote: LPRO time nuts, Is there a complete set of schematics available for the Efratom LPRO-101 Rubidium oscillator? I have the Repair reference guide by Fred de Vries, PE1FBO, Revision 6, 2010 which is very useful, but unfortunately it includes only some of the schematics. What I'm looking for is a schematic of the 20 MHz osc section and it's control loop. In an ongoing effort to initially see how good, and ultimately how simple, I can improve the performance of a LPRO based oscillator system, I've started with the basics by using a low noise 10811 as a clean up osc to improve the under 100 sec noise. To minimize any room temperature swings from effecting the performance, I've added an active temperature controller to keep the base plate heat sink temperature constant. To remove long term daily drift and get absolute freq accuracy, I'm using the C-field to discipline it to GPS. For that I'm using the LPRO as the external oscillator for a Tbolt and set the Tbolt's extended time constant at 12 to 24 hrs using Lady Heather. The results to date are very encouraging and show substantial improvement over the whole tau range from 0.01 sec out to days, in effect providing a low cost Cs substitute. ws attachment: ws-rb-05-19-2011.gif___ 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] TEK P6430 temp probes are available
Hello The net: For use with your Tektronix thermometer/temperature monitor: 5 each TEK 010-6430-00, P6430 Temp Probe, Status: unknown, found in my garage when cleaning out. Looks like a scope probe with a LEMO connector on one end. For postage to you, otherwise Free, first come first served. For use when you are monitoring the temp of your xtal oven. Stan, W1LE Cape Cod ___ 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] TEK P6430 temp probes are available
Thanks for the interest. 5 each are spoken for. Stan On 6/1/2011 8:48 PM, Stan, W1LE wrote: Hello The net: For use with your Tektronix thermometer/temperature monitor: 5 each TEK 010-6430-00, P6430 Temp Probe, Status: unknown, found in my garage when cleaning out. Looks like a scope probe with a LEMO connector on one end. For postage to you, otherwise Free, first come first served. For use when you are monitoring the temp of your xtal oven. Stan, W1LE Cape Cod ___ 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] LightSquared's Wireless Network Interferes With GPS
From the WSJ: === LightSquared's Wireless Network Interferes With GPS By AMY SCHATZ WASHINGTONLightSquared's plan to launch a new national wireless broadband network faces a setback as preliminary tests suggest the start-up's network could knock out some GPS systems. Reuters Harbinger's Philip Falcone shown at an investor conference last month. LightSquared's interference problems could slow down FCC approval of its new network and create problems for other companies including its primary financial backer, Harbinger Capital Partners, the hedge fund led by Philip Falcone. Harbinger and its affiliates have put $2.9 billion of assets into LightSquared, according to a LightSquared statement. Harbinger has run into a series of other problems recently, as investors have withdrawn money and regulators have probed certain of the firm's trades from several years ago as well as a loan made by the fund to Mr. Falcone in 2009, which has been repaid. The company has said it is cooperating with regulators The airwaves Lightsquare uses are located close to the airwaves used by satellite navigation systems, and GPS usersparticularly the military and policeworry the company's plan to install 40,000 antennas around the country will overpower GPS signals. GPS signals are used for navigation and location systems for vehicles, aircraft and defense and public-safety agencies. LightSquared has signed deals with a number of companies, including Best Buy Co. and Leap Wireless International Inc., to offer wholesale wireless Internet service, and had originally planned to launch limited service later this year. Delays for LightSquared also could be a problem for ATT Inc., which has cited LightSquared as a viable competitor to regulators in the antitrust review of its $39 billion deal to acquire T-Mobile USA. LightSquared officials acknowledge their network could knock out some GPS systems but say that they've developed technical fixes that could solve the problem. LightSquared and GPS can and will be able to coexist peacefully, said Jeff Carlisle, LightSquared's executive vice president for regulatory affairs and public policy on Wednesday. We're committed to identifying and resolving the issues through this process. Later this month, the company and GPS makers are scheduled to deliver a planned report to the Federal Communications Commission about any interference issues that arose from tests held recently in New Mexico. Public safety officials near the testing area reported LightSquared's tower knocked out their GPS systems in some areas, according to Bill Range, New Mexico's E-911 program director, in a letter to federal officials. On Friday, construction giant Deere Co. also reported to the FCC the risk of severe interference on its tractors GPS systems from as far as 20 miles away from a LightSquared tower and a complete loss of service between four miles and 22 miles. Initial, unofficial tests by GPS users suggest that high-performance GPS equipment used by the aviation, defense and other industries would be more likely to be hobbled by LightSquared's network than the cheaper devices used by most consumers. If existing GPS equipment needs to be fixed to avoid interference, it's not clear who would pay for those alternations. LightSquared's airwaves were originally set aside for satellite use but in January the FCC agreed to allow the company to build a terrestrial-only network. LightSquared plans to operate a wholesale network that would lease airwaves to other carriers that want to offer high-speed wireless Internet service. Earlier this year, the Defense Department, Department of Homeland Security, the Federal Aviation Administration and other agencies raised concerns to the FCC about approving LightSquared's new network. A group of 34 Senators also sent the agency a letter on May 19 raising concerns about the issue, after lobbying by the GPS community. -John ___ 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.
