|
"Tim Wescott" wrote in message ... Eddie Haskel wrote: Rumor has it that QST featured an article in a January/1930 or January/1935 issue on the subject of homebrew transmitter crystals - how cut, lap, and mount them. If anyone has QST on CDROM for those years, I'd sure appreciate if you could take a look. Ah yes..the good 'ol days of grinding FT-243 Xtals with toothpaste(or comet)to go up, and writing on the blank with #2 pencil lead to take them down a few Kilocycles....Eddie No, the good _really_ 'ol days of taking a chunk of quartz, whacking pieces off of it with a mud saw, hand lapping the saw marks off and mounting it in a home-made holder. That namby-pamby FT-243 wasn't invented until just before WW-II. The same magazine has an article about the blind ham who built his own equipment. Soldering by feel. There were giants in those days... -- Tim Wescott Wescott Design Services http://www.wescottdesign.com |
"Tim Wescott" wrote in message ... Eddie Haskel wrote: Yes Mrs. Cleaver... ....Eddie [...snip...] The same magazine has an article about the blind ham who built his own equipment. Soldering by feel. There were giants in those days... Tim Wescott O U C H !! |
"Tim Wescott" wrote in message ... Eddie Haskel wrote: Yes Mrs. Cleaver... ....Eddie [...snip...] The same magazine has an article about the blind ham who built his own equipment. Soldering by feel. There were giants in those days... Tim Wescott O U C H !! |
actually, it is a lot easier to simply etch or grind away some of the xtal, then check it with a grid dip oscillator for sharp dip, no need to remount and test ;-) An old Hints and Kinks IIRC. This could be really handy if you wanted to make a xtal filter and needed to really match and control the xtal freq offsets (what, 3.5179 Mhz xtals from TV color burst sources?) ;-) and how about drilling a small hold in the holder so you could tread a small bolt to put pressure on the xtal holder plates, shifting the xtal freq. around like a xtal controlled VFO - but only a handful of khz ;-) Still, very solid (pun intended) freq. source that can be varied around enough to avoid QRM at minimal cost and effort for QRPers and so on? ;-) Wasn't there a recent historical article in QST on the role of the quartz xtal industry in WWII, how they figured out overtone osc. issues and so on? Given that some sources ask $12 and up for scanner and ham crystals, these costs add up rather fast if you need to replace a bunch of xtals in a scanner. So the search for alternatives seems quite worthwhile ;-) regards bobm -- ************************************************** ********************* * Robert Monaghan POB 752182 Southern Methodist Univ. Dallas Tx 75275 * ********************Standard Disclaimers Apply************************* |
actually, it is a lot easier to simply etch or grind away some of the xtal, then check it with a grid dip oscillator for sharp dip, no need to remount and test ;-) An old Hints and Kinks IIRC. This could be really handy if you wanted to make a xtal filter and needed to really match and control the xtal freq offsets (what, 3.5179 Mhz xtals from TV color burst sources?) ;-) and how about drilling a small hold in the holder so you could tread a small bolt to put pressure on the xtal holder plates, shifting the xtal freq. around like a xtal controlled VFO - but only a handful of khz ;-) Still, very solid (pun intended) freq. source that can be varied around enough to avoid QRM at minimal cost and effort for QRPers and so on? ;-) Wasn't there a recent historical article in QST on the role of the quartz xtal industry in WWII, how they figured out overtone osc. issues and so on? Given that some sources ask $12 and up for scanner and ham crystals, these costs add up rather fast if you need to replace a bunch of xtals in a scanner. So the search for alternatives seems quite worthwhile ;-) regards bobm -- ************************************************** ********************* * Robert Monaghan POB 752182 Southern Methodist Univ. Dallas Tx 75275 * ********************Standard Disclaimers Apply************************* |
Steve Nosko wrote:
"H. Peter Friedrichs" wrote in message link.net... Hello, All: Rumor has it that QST featured an article in a January/1930 or January/1935 issue on the subject of homebrew transmitter crystals - how cut, lap, and mount them. If anyone has QST on CDROM for those years, I'd sure appreciate if you could take a look. Remove XXX's and ZZZ's if you wish to reply directly, and thanks. Pete AC7ZL Pete, I have my Dad's grinding stuff, but don't do it. One thing to keep in mind, and I don't know the details, but remember that the crystal activity is effected by the edges. Grinding the edges is one of the more esoteric aspects. The trick isn't the edges but keeping the two surfaces parallel and flat. The procedure is to grind a little and check the activity. If it is down try to grind the center or edges and check again. If it gets better then go back to to grinding and trying to keep it flat. Anyway that is the method I used. Bill K7NOM |
Steve Nosko wrote:
"H. Peter Friedrichs" wrote in message link.net... Hello, All: Rumor has it that QST featured an article in a January/1930 or January/1935 issue on the subject of homebrew transmitter crystals - how cut, lap, and mount them. If anyone has QST on CDROM for those years, I'd sure appreciate if you could take a look. Remove XXX's and ZZZ's if you wish to reply directly, and thanks. Pete AC7ZL Pete, I have my Dad's grinding stuff, but don't do it. One thing to keep in mind, and I don't know the details, but remember that the crystal activity is effected by the edges. Grinding the edges is one of the more esoteric aspects. The trick isn't the edges but keeping the two surfaces parallel and flat. The procedure is to grind a little and check the activity. If it is down try to grind the center or edges and check again. If it gets better then go back to to grinding and trying to keep it flat. Anyway that is the method I used. Bill K7NOM |
Bob Monaghan ) writes:
Wasn't there a recent historical article in QST on the role of the quartz xtal industry in WWII, how they figured out overtone osc. issues and so on? Given that some sources ask $12 and up for scanner and ham crystals, these costs add up rather fast if you need to replace a bunch of xtals in a scanner. So the search for alternatives seems quite worthwhile ;-) But they already figured out the solution, thirty years ago, and it did not require going to the quarry for quartz and digging out old QSTs. The need for a lot of crystals luckily coincided with digital ICs, so before most people could get around to paying for all the crystals to fill out a mult-channel unit, synthesizers came along so you only needed one crystal. About as soon as it could be done practically, hams built them and wrote up articles in the ham magazines. Anyone who decides to make their own crystals today, other than for the sake of doing so (and I admit it would be an interesting thing to try), will likely find they can't go for the subminiature look, and probably will find that putting effort into building a synthesizer still makes sense if you need more than a few crystals. Michael VE2BVW |
Bob Monaghan ) writes:
Wasn't there a recent historical article in QST on the role of the quartz xtal industry in WWII, how they figured out overtone osc. issues and so on? Given that some sources ask $12 and up for scanner and ham crystals, these costs add up rather fast if you need to replace a bunch of xtals in a scanner. So the search for alternatives seems quite worthwhile ;-) But they already figured out the solution, thirty years ago, and it did not require going to the quarry for quartz and digging out old QSTs. The need for a lot of crystals luckily coincided with digital ICs, so before most people could get around to paying for all the crystals to fill out a mult-channel unit, synthesizers came along so you only needed one crystal. About as soon as it could be done practically, hams built them and wrote up articles in the ham magazines. Anyone who decides to make their own crystals today, other than for the sake of doing so (and I admit it would be an interesting thing to try), will likely find they can't go for the subminiature look, and probably will find that putting effort into building a synthesizer still makes sense if you need more than a few crystals. Michael VE2BVW |
Michael Black wrote:
Bob Monaghan ) writes: Wasn't there a recent historical article in QST on the role of the quartz xtal industry in WWII, how they figured out overtone osc. issues and so on? Given that some sources ask $12 and up for scanner and ham crystals, these costs add up rather fast if you need to replace a bunch of xtals in a scanner. So the search for alternatives seems quite worthwhile ;-) But they already figured out the solution, thirty years ago, and it did not require going to the quarry for quartz and digging out old QSTs. The need for a lot of crystals luckily coincided with digital ICs, so before most people could get around to paying for all the crystals to fill out a mult-channel unit, synthesizers came along so you only needed one crystal. About as soon as it could be done practically, hams built them and wrote up articles in the ham magazines. Anyone who decides to make their own crystals today, other than for the sake of doing so (and I admit it would be an interesting thing to try), will likely find they can't go for the subminiature look, and probably will find that putting effort into building a synthesizer still makes sense if you need more than a few crystals. Michael VE2BVW Absolutely: You should only make your own crystals for the same reasons you'd knap your own stone tools -- to understand how it was done back in the day, and to have some thing to show off to friends. You could get crystals much faster by cleaning toilets at McDonald's and buying them at $12 a pop than you could making them from scratch. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com |
| All times are GMT +1. The time now is 02:31 PM. |
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
RadioBanter.com