Re: [time-nuts] optically excite a quartz crystal?
I'll have to check (dig it out from under a pile of gear.) but if I remember correctly the HRO receiver (at least the early, pre-war, ones) had a 'non-contact' crystal holder for the IF notch filter. The crystal was a block about 1/2 square and a bit less thick (-ish) and fitted loosely between two support plates which incorporated the electrodes. It was certainly not a tight fit and the crystal could be easily removed. Paul ReevesG8GJA -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chuck Harris Sent: 21 April 2014 14:01 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] optically excite a quartz crystal? I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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] optically excite a quartz crystal?
On Mon, 21 Apr 2014 17:12:54 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Optical excitation of quartz resonators: Electronics Letters http://digital-library.theiet.org/content/journals/el, Volume 18, Issue 9 http://digital-library.theiet.org/content/journals/el/18/9, 29 April 1982, p. 381 – 382 Thanks Bruce! For those who dont want to buy the paper, here a short summary: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal Attila Kinali -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ 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] optically excite a quartz crystal?
On 04/21/2014 11:40 AM, Attila Kinali wrote: On Mon, 21 Apr 2014 17:12:54 +1200 Bruce Griffiths bruce.griffi...@xtra.co.nz wrote: Optical excitation of quartz resonators: Electronics Letters http://digital-library.theiet.org/content/journals/el, Volume 18, Issue 9 http://digital-library.theiet.org/content/journals/el/18/9, 29 April 1982, p. 381 – 382 Thanks Bruce! For those who dont want to buy the paper, here a short summary: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal 10 mW laser is reasonable. What levels of signal where they getting? Cheers, Magnus ___ 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] optically excite a quartz crystal?
I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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] optically excite a quartz crystal?
In my over 50 years of active ham radio experience as well as in my professional one, I have literally taken apart 10s of thousands of crystals, and, have never seen a single on where there has not been a physical contact with the quartz. That of course includes the most common FT-243. Regards - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Sunday, April 20, 2014 9:06 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] optically excite a quartz crystal? Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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] optically excite a quartz crystal?
Hi If you look closely at most of them, the plates are not flat. They are higher on the edges than in the center. There’s a gap in the middle. If you don’t have the gap, the blank is constrained by the big heavy plate. That damps the resonance and lowers the Q. Bob On Apr 21, 2014, at 9:00 AM, Chuck Harris cfhar...@erols.com wrote: I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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] optically excite a quartz crystal?
On Mon, 21 Apr 2014 14:54:12 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal 10 mW laser is reasonable. What levels of signal where they getting? 6.2mV, with an real laser incident power of 5mW (the AOM ate half of the power) Attila Kinali -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ 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] optically excite a quartz crystal?
Agree there are some like that, but, only a few. A large spring loaded plate is not going to dampen a piece of quartz vibrating in the MHz range at all. Granted, the sealed, and metalized construction is a better one, but it is mostly done to minimize shock and impurities. - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Monday, April 21, 2014 9:17 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] optically excite a quartz crystal? Hi If you look closely at most of them, the plates are not flat. They are higher on the edges than in the center. There's a gap in the middle. If you don't have the gap, the blank is constrained by the big heavy plate. That damps the resonance and lowers the Q. Bob On Apr 21, 2014, at 9:00 AM, Chuck Harris cfhar...@erols.com wrote: I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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] optically excite a quartz crystal?
Hi One of the reasons for going to plated electrodes was to control the damping on the resonator. You control plating thickness fairly tightly for this reason. A great big lump of iron on your vibrating area does indeed damp it. Bob On Apr 21, 2014, at 9:29 AM, Mike Feher mfe...@eozinc.com wrote: Agree there are some like that, but, only a few. A large spring loaded plate is not going to dampen a piece of quartz vibrating in the MHz range at all. Granted, the sealed, and metalized construction is a better one, but it is mostly done to minimize shock and impurities. - Mike Mike B. Feher, EOZ Inc. 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 office 908-902-3831 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Monday, April 21, 2014 9:17 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] optically excite a quartz crystal? Hi If you look closely at most of them, the plates are not flat. They are higher on the edges than in the center. There's a gap in the middle. If you don't have the gap, the blank is constrained by the big heavy plate. That damps the resonance and lowers the Q. Bob On Apr 21, 2014, at 9:00 AM, Chuck Harris cfhar...@erols.com wrote: I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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. ___ 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] optically excite a quartz crystal?
On 04/21/2014 03:18 PM, Attila Kinali wrote: On Mon, 21 Apr 2014 14:54:12 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal 10 mW laser is reasonable. What levels of signal where they getting? 6.2mV, with an real laser incident power of 5mW (the AOM ate half of the power) Cool. Today we use semiconductor lasers that we can modulate directly, so no need for the AOM on the NeHe laser. Cheers, Magnus ___ 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] optically excite a quartz crystal?
Hi If you are going to thermally excite the resonator, and measure the resonance optically, there’s no reason at all to use quartz. There are other materials with much higher acoustic Q than quartz. Bob On Apr 21, 2014, at 9:47 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 04/21/2014 03:18 PM, Attila Kinali wrote: On Mon, 21 Apr 2014 14:54:12 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal 10 mW laser is reasonable. What levels of signal where they getting? 6.2mV, with an real laser incident power of 5mW (the AOM ate half of the power) Cool. Today we use semiconductor lasers that we can modulate directly, so no need for the AOM on the NeHe laser. Cheers, Magnus ___ 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] optically excite a quartz crystal?
No. There is just a little rectangular quartz wafer. No plating. In fact, post WWII, when many ham transmitters were 'rock bound' (ie: crystal conteolled) it was common pratice to regrind mil surplus rystals to move them into the ham banda. Apparently, some were also etched using a cleanser called Whink, which contains a flourine compound. Also, some advocated applying graphite from a pencil lead was used to decrease the frequency. If the crystal ativity was low, they were taken appart and cleaned. -John == I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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] optically excite a quartz crystal?
Hi Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. Ammonium bi-flouride and water was the most common etchant in that era. There are a number of papers about the whole deal in the FCS, and many stories told by those who were part of the changes. Bob On Apr 21, 2014, at 10:10 AM, J. Forster j...@quikus.com wrote: No. There is just a little rectangular quartz wafer. No plating. In fact, post WWII, when many ham transmitters were 'rock bound' (ie: crystal conteolled) it was common pratice to regrind mil surplus rystals to move them into the ham banda. Apparently, some were also etched using a cleanser called Whink, which contains a flourine compound. Also, some advocated applying graphite from a pencil lead was used to decrease the frequency. If the crystal ativity was low, they were taken appart and cleaned. -John == I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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] optically excite a quartz crystal?
In message a5032606-d7d7-4231-b1bd-434670274...@rtty.us, Bob Camp writes: Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. The story is slightly more interesting than that: Blileys crystals were almost totally without these problems, but they wouldn't tell why that might be. In the end the government put a lot of pressure on Bliley to squeeze out the manufacturing secret. The secret was etching. To keep it secret, Bliley had called it something along the lines of X-Grind and not applied for a patent. The Government forced Bliley to share the etching secret without giving any compensation, and the Blileys were bitter about that for the rest of their lifes. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] optically excite a quartz crystal?
Who said they were plated? -Chuck Harris J. Forster wrote: No. There is just a little rectangular quartz wafer. No plating. In fact, post WWII, when many ham transmitters were 'rock bound' (ie: crystal conteolled) it was common pratice to regrind mil surplus rystals to move them into the ham banda. Apparently, some were also etched using a cleanser called Whink, which contains a flourine compound. Also, some advocated applying graphite from a pencil lead was used to decrease the frequency. If the crystal ativity was low, they were taken appart and cleaned. -John == I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris ___ 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] optically excite a quartz crystal?
The etching referred to was by post-war hams, -John === Hi Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. Ammonium bi-flouride and water was the most common etchant in that era. There are a number of papers about the whole deal in the FCS, and many stories told by those who were part of the changes. Bob On Apr 21, 2014, at 10:10 AM, J. Forster j...@quikus.com wrote: No. There is just a little rectangular quartz wafer. No plating. In fact, post WWII, when many ham transmitters were 'rock bound' (ie: crystal conteolled) it was common pratice to regrind mil surplus rystals to move them into the ham banda. Apparently, some were also etched using a cleanser called Whink, which contains a flourine compound. Also, some advocated applying graphite from a pencil lead was used to decrease the frequency. If the crystal ativity was low, they were taken appart and cleaned. -John == I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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. ___ 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] optically excite a quartz crystal?
Hi As with all “good stories” there are many versions told by many people. I’ve heard far to many mutually contradictory versions to have any real idea what’s true. You are correct that etching was a known process in the 1930’s and that it had been used by various people at various times. Since it added time (and complexity) to the process, it got dropped by most people to speed up production … Bob On Apr 21, 2014, at 10:51 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message a5032606-d7d7-4231-b1bd-434670274...@rtty.us, Bob Camp writes: Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. The story is slightly more interesting than that: Blileys crystals were almost totally without these problems, but they wouldn't tell why that might be. In the end the government put a lot of pressure on Bliley to squeeze out the manufacturing secret. The secret was etching. To keep it secret, Bliley had called it something along the lines of X-Grind and not applied for a patent. The Government forced Bliley to share the etching secret without giving any compensation, and the Blileys were bitter about that for the rest of their lifes. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] optically excite a quartz crystal?
Hi Well I can name at least one post war ham (me at age 14) who did not understand the need for etch after grinding… Bob On Apr 21, 2014, at 11:21 AM, J. Forster j...@quikus.com wrote: The etching referred to was by post-war hams, -John === Hi Early in the WWII era, quartz blanks were not commonly etched after begin ground / polished to frequency. This left debris on the surface of the blank. The net result was that the resonators failed after a period of time in the field, especially under damp conditions. The problem got so bad that it actually threatened the ability to communicate in 1942. A fairly high level team looked into the issue and etching of blanks (and a few other mods) were made a mandatory part of all crystals suppled to the government. Ammonium bi-flouride and water was the most common etchant in that era. There are a number of papers about the whole deal in the FCS, and many stories told by those who were part of the changes. Bob On Apr 21, 2014, at 10:10 AM, J. Forster j...@quikus.com wrote: No. There is just a little rectangular quartz wafer. No plating. In fact, post WWII, when many ham transmitters were 'rock bound' (ie: crystal conteolled) it was common pratice to regrind mil surplus rystals to move them into the ham banda. Apparently, some were also etched using a cleanser called Whink, which contains a flourine compound. Also, some advocated applying graphite from a pencil lead was used to decrease the frequency. If the crystal ativity was low, they were taken appart and cleaned. -John == I'm puzzling over this statement. The FT-243's I have seen have a spring that squishes the quartz blank between the electrodes. They aren't plated onto the quartz, but they are still in intimate mechanical and electrical contact. -Chuck Harris Bob Camp wrote: Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob ___ 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. ___ 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] optically excite a quartz crystal?
Bob, We all start somewhere. Today one buys aged equipment with fancy synthesis so that fooling around with crystals, etching or graphiting them won't be necessary. Hell, someone taking the time to calibrate their transceiver is rare these days. Cheers, Magnus ___ 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] optically excite a quartz crystal?
When this question was first posed, AOM's first jumped to my mind. An AOM (sometimes AOD) is an Acousto-Optic Modulator that works by setting up an acoustic wave in a crystal. When a laser is directed through (or reflected by) an AOM, it is deflected. One way to think about this is the crystal lattice deforms with the period of the acoustic wave. The lattice deformations form a grating of regions of varying indices of refraction which produce varying phase delay. This steers the beam just as a grating would. Another way of thinking about it is the 'phonon's' momentum and the photon's momentum add producing a deflection (like two billiard balls colliding). This might seem impossible, but the math works out exactly.. Another nice thing is, if you recall, the EM field produced in the far-field of a coherent EM wave impinging on a grating is the Fourier Transform of the grating itself. In something like a CD, the grating has hard edges, producing lots of harmonic content. AOMs look like sine waves, most of the energy ends up in the deflected beam. AOMs are often constructed using quartz crystals because they are fairly broadband (optically) and piezoelectric. The piezoelectric properties make it easy to set up the acoustic wave in the crystal. The key difference is, AOMs are typically designed to absorb as little power as possible (power absorption is their primary failure mechanism). Depending on your laser, you might want to find an AOM that is less transparent in your excitation regime. That said, you can get a lot of energy out of lasers these days. Megawatt pulses are not impossible with something like a Kerr-lens mode locked laser. This results in extremely high electric fields (MW pulse in 0.1 mm^2). Andy Bardagjy bardagjy.com On Apr 21, 2014, at 6:47 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 04/21/2014 03:18 PM, Attila Kinali wrote: On Mon, 21 Apr 2014 14:54:12 +0200 Magnus Danielson mag...@rubidium.dyndns.org wrote: They used a 10mW HeNe laser, modulated with 1kHz to 1MHz on various quartz cuts (X+5°, DT, AT) and could measure oscillations of the quartz using metal electrodes. The mechanism of exitation was photothermal 10 mW laser is reasonable. What levels of signal where they getting? 6.2mV, with an real laser incident power of 5mW (the AOM ate half of the power) Cool. Today we use semiconductor lasers that we can modulate directly, so no need for the AOM on the NeHe laser. Cheers, Magnus ___ 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] optically excite a quartz crystal?
In message aabkxjbn5aj3w...@smtpout04.dca.untd.com, cdel...@juno.com writes: After reading about how the BVA oscillators avoid the problems of on crystal electrodes I was wondering if anyone has tried to optically excite a quartz crystal in an oscillator? I can see optical detection, but I have a hard time imagining how you would excite it opticaly ? You can obviously hammer it with a wavelength quartz absorbs, but that turns into heat and I somewhat doubt you can get a heat/cooling cycle to run at 10 MHz, even in perfect quartz ? -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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] optically excite a quartz crystal?
Hi Corby, On 04/20/2014 07:35 PM, cdel...@juno.com wrote: After reading about how the BVA oscillators avoid the problems of on crystal electrodes I was wondering if anyone has tried to optically excite a quartz crystal in an oscillator? (Use a modulated laser to drive the bare crystal, and a photodetector setup to detect and provide feedback?) Seems like it might work. Any comments? I only wonder if you can get sufficient drive-level that way. I haven't heard about a way to drive quartz optically even if I can consider a few different mechanisms. You have any papers on that? Optically sensing the vibration I consider trivial. Cheers, Magnus ___ 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] optically excite a quartz crystal?
If laser excitation won't work, how about sound, as an opera singer breaking a glass? Use feedback control to bring the driven crystal to resonance with the free crystal. Might need to go down to 100 KHz to make this practical. Speaking of practical, how would you levitate the free crystal? Bill Hawkins -Original Message- From: cdel...@juno.com Sent: Sunday, April 20, 2014 12:35 PM After reading about how the BVA oscillators avoid the problems of on crystal electrodes I was wondering if anyone has tried to optically excite a quartz crystal in an oscillator? (Use a modulated laser to drive the bare crystal, and a photodetector setup to detect and provide feedback?) Seems like it might work. Any comments? Corby ___ 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] optically excite a quartz crystal?
On Sun, 20 Apr 2014 10:35:08 -0700 cdel...@juno.com wrote: After reading about how the BVA oscillators avoid the problems of on crystal electrodes I was wondering if anyone has tried to optically excite a quartz crystal in an oscillator? (Use a modulated laser to drive the bare crystal, and a photodetector setup to detect and provide feedback?) Seems like it might work. Any comments? I am not really sure about that. (Disclaimer: my knowledge about solid state physics and piezo-electric devices is at best rudimentary, so please correct me if i'm wrong) The oscillations of the quartz crystal are deformations of the crystal lattice. This deformation is induced by applying an electrical field and coupled into the lattice over the piezo-electric effect. The wavelength of the electromagnetic field is usually much much larger than the dimensions of the crystal involved. As such, the field can be seen as constant trough the crystal. I.e. the field induced strain on the lattice is constant trough the whole length. On the other hand, the wavelength of lasers is in the order of a couple thousand times the lattice constant (approx 0.5nm). I.e. the field of a laser within a quartz crystal wouldn't be constant if one would be to use a crystal in the sweet spot region between 1MHz and 10MHz. Using two lasers with a ~10MHz frequency difference and using two photon absorbtion will probably yield to a very small energy coupling to induce any measurable oscillation, if it is possible at all (i don't know of any effect that would translate a two photon absorption into lattice oscillations). Thus, i don't think it would be possible to induce oscillations in a quartz crystal using a laser based system. On the other hand, there are currently experiments running to use lasers to generate RF frequency refernces coupled to the interogation of atomic clocks (see e.g. [1]) and the results are comparable to ultra low noise crystal oscillators. Attila Kinali [1] State-of-the-Art RF Signal Generation From Optical Frequency Division. by Hati, Nelson, Barnes, Lirette, et. al., 2013 -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ 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] optically excite a quartz crystal?
Quartz is piezoelectric, so it deforms due to electrostatic fields and vice versa. This is exactly what is being used in quartz oscillators. For the BVA, the resonator is hanging in bridges of the same quartz crystal it is being cut out from, and the orientation of the blank is such that these bridges have minimal impact on the frequency. The other aspect is that BVAs have the electrodes on concave quartz pieces just a few micrometers from the surface of the resonator blank. These pieces is really the expensive part of the BVA sandwich. There are a couple of ways to monitor the crystal using optical measures. The manipulation and sensing is done by electrostatic means, while the crystal itself is resonant by means of acoustical waves. So well, I guess you could be using another 10 MHz crystal as an acoustical transmission source... but why is the big question. When someone figures out why this is a super solution, I bet they won't tell us until the patent has been accepted. Cheers, Magnus On 04/20/2014 11:03 PM, Bill Hawkins wrote: If laser excitation won't work, how about sound, as an opera singer breaking a glass? Use feedback control to bring the driven crystal to resonance with the free crystal. Might need to go down to 100 KHz to make this practical. Speaking of practical, how would you levitate the free crystal? Bill Hawkins -Original Message- From: cdel...@juno.com Sent: Sunday, April 20, 2014 12:35 PM After reading about how the BVA oscillators avoid the problems of on crystal electrodes I was wondering if anyone has tried to optically excite a quartz crystal in an oscillator? (Use a modulated laser to drive the bare crystal, and a photodetector setup to detect and provide feedback?) Seems like it might work. Any comments? Corby ___ 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] optically excite a quartz crystal?
It seems that it would be relatively easy to apply an electric field to a quartz plate without actually making physical contact. However, Star Trek's force field hasn't been invented yet so there must be some way to support the plate. If you could arrange to support it on the nodes you could excite it with a non contact electric field and then read it out with a laser. Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com - Original Message - From: Attila Kinali att...@kinali.ch To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, April 20, 2014 2:50 PM Subject: Re: [time-nuts] optically excite a quartz crystal? On Sun, 20 Apr 2014 10:35:08 -0700 cdel...@juno.com wrote: After reading about how the BVA oscillators avoid the problems of on crystal electrodes I was wondering if anyone has tried to optically excite a quartz crystal in an oscillator? (Use a modulated laser to drive the bare crystal, and a photodetector setup to detect and provide feedback?) Seems like it might work. Any comments? I am not really sure about that. (Disclaimer: my knowledge about solid state physics and piezo-electric devices is at best rudimentary, so please correct me if i'm wrong) The oscillations of the quartz crystal are deformations of the crystal lattice. This deformation is induced by applying an electrical field and coupled into the lattice over the piezo-electric effect. The wavelength of the electromagnetic field is usually much much larger than the dimensions of the crystal involved. As such, the field can be seen as constant trough the crystal. I.e. the field induced strain on the lattice is constant trough the whole length. On the other hand, the wavelength of lasers is in the order of a couple thousand times the lattice constant (approx 0.5nm). I.e. the field of a laser within a quartz crystal wouldn't be constant if one would be to use a crystal in the sweet spot region between 1MHz and 10MHz. Using two lasers with a ~10MHz frequency difference and using two photon absorbtion will probably yield to a very small energy coupling to induce any measurable oscillation, if it is possible at all (i don't know of any effect that would translate a two photon absorption into lattice oscillations). Thus, i don't think it would be possible to induce oscillations in a quartz crystal using a laser based system. On the other hand, there are currently experiments running to use lasers to generate RF frequency refernces coupled to the interogation of atomic clocks (see e.g. [1]) and the results are comparable to ultra low noise crystal oscillators. Attila Kinali [1] State-of-the-Art RF Signal Generation From Optical Frequency Division. by Hati, Nelson, Barnes, Lirette, et. al., 2013 -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ 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. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ 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] optically excite a quartz crystal?
Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob On Apr 20, 2014, at 8:47 PM, Max Robinson m...@maxsmusicplace.com wrote: It seems that it would be relatively easy to apply an electric field to a quartz plate without actually making physical contact. However, Star Trek's force field hasn't been invented yet so there must be some way to support the plate. If you could arrange to support it on the nodes you could excite it with a non contact electric field and then read it out with a laser. Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com - Original Message - From: Attila Kinali att...@kinali.ch To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, April 20, 2014 2:50 PM Subject: Re: [time-nuts] optically excite a quartz crystal? On Sun, 20 Apr 2014 10:35:08 -0700 cdel...@juno.com wrote: After reading about how the BVA oscillators avoid the problems of on crystal electrodes I was wondering if anyone has tried to optically excite a quartz crystal in an oscillator? (Use a modulated laser to drive the bare crystal, and a photodetector setup to detect and provide feedback?) Seems like it might work. Any comments? I am not really sure about that. (Disclaimer: my knowledge about solid state physics and piezo-electric devices is at best rudimentary, so please correct me if i'm wrong) The oscillations of the quartz crystal are deformations of the crystal lattice. This deformation is induced by applying an electrical field and coupled into the lattice over the piezo-electric effect. The wavelength of the electromagnetic field is usually much much larger than the dimensions of the crystal involved. As such, the field can be seen as constant trough the crystal. I.e. the field induced strain on the lattice is constant trough the whole length. On the other hand, the wavelength of lasers is in the order of a couple thousand times the lattice constant (approx 0.5nm). I.e. the field of a laser within a quartz crystal wouldn't be constant if one would be to use a crystal in the sweet spot region between 1MHz and 10MHz. Using two lasers with a ~10MHz frequency difference and using two photon absorbtion will probably yield to a very small energy coupling to induce any measurable oscillation, if it is possible at all (i don't know of any effect that would translate a two photon absorption into lattice oscillations). Thus, i don't think it would be possible to induce oscillations in a quartz crystal using a laser based system. On the other hand, there are currently experiments running to use lasers to generate RF frequency refernces coupled to the interogation of atomic clocks (see e.g. [1]) and the results are comparable to ultra low noise crystal oscillators. Attila Kinali [1] State-of-the-Art RF Signal Generation From Optical Frequency Division. by Hati, Nelson, Barnes, Lirette, et. al., 2013 -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ 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. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ 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] optically excite a quartz crystal?
Ya, I remember those FT243s. I used some when I was a novice KN4ODS. Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com - Original Message - From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, April 20, 2014 8:05 PM Subject: Re: [time-nuts] optically excite a quartz crystal? Hi The WWII era FT-243 is one example of a crystal that has the active portion of the electrodes separated from the resonator by an air gap. There are lots of similar holders from that era that do pretty much the same thing. Non-contacting electrodes are not very new. Bob On Apr 20, 2014, at 8:47 PM, Max Robinson m...@maxsmusicplace.com wrote: It seems that it would be relatively easy to apply an electric field to a quartz plate without actually making physical contact. However, Star Trek's force field hasn't been invented yet so there must be some way to support the plate. If you could arrange to support it on the nodes you could excite it with a non contact electric field and then read it out with a laser. Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com - Original Message - From: Attila Kinali att...@kinali.ch To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sunday, April 20, 2014 2:50 PM Subject: Re: [time-nuts] optically excite a quartz crystal? On Sun, 20 Apr 2014 10:35:08 -0700 cdel...@juno.com wrote: After reading about how the BVA oscillators avoid the problems of on crystal electrodes I was wondering if anyone has tried to optically excite a quartz crystal in an oscillator? (Use a modulated laser to drive the bare crystal, and a photodetector setup to detect and provide feedback?) Seems like it might work. Any comments? I am not really sure about that. (Disclaimer: my knowledge about solid state physics and piezo-electric devices is at best rudimentary, so please correct me if i'm wrong) The oscillations of the quartz crystal are deformations of the crystal lattice. This deformation is induced by applying an electrical field and coupled into the lattice over the piezo-electric effect. The wavelength of the electromagnetic field is usually much much larger than the dimensions of the crystal involved. As such, the field can be seen as constant trough the crystal. I.e. the field induced strain on the lattice is constant trough the whole length. On the other hand, the wavelength of lasers is in the order of a couple thousand times the lattice constant (approx 0.5nm). I.e. the field of a laser within a quartz crystal wouldn't be constant if one would be to use a crystal in the sweet spot region between 1MHz and 10MHz. Using two lasers with a ~10MHz frequency difference and using two photon absorbtion will probably yield to a very small energy coupling to induce any measurable oscillation, if it is possible at all (i don't know of any effect that would translate a two photon absorption into lattice oscillations). Thus, i don't think it would be possible to induce oscillations in a quartz crystal using a laser based system. On the other hand, there are currently experiments running to use lasers to generate RF frequency refernces coupled to the interogation of atomic clocks (see e.g. [1]) and the results are comparable to ultra low noise crystal oscillators. Attila Kinali [1] State-of-the-Art RF Signal Generation From Optical Frequency Division. by Hati, Nelson, Barnes, Lirette, et. al., 2013 -- I pity people who can't find laughter or at least some bit of amusement in the little doings of the day. I believe I could find something ridiculous even in the saddest moment, if necessary. It has nothing to do with being superficial. It's a matter of joy in life. -- Sophie Scholl ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe
Re: [time-nuts] optically excite a quartz crystal?
Optical excitation of quartz resonators: Electronics Letters http://digital-library.theiet.org/content/journals/el, Volume 18, Issue 9 http://digital-library.theiet.org/content/journals/el/18/9, 29 April 1982, p. 381 – 382 Bruce ___ 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.
