If you want a complete do it yourself treatise on crystals, you will have to go back to the 1935 QST magazines, November and December if I recall. In those articles you will learn how to make a saw to cut raw crystal, the type of crystal to use and how to check the alignment of the quartz for the cut to make overtone or fundamental types, and the formula that approximates the thickness of crystal to cut for a particular frequency. Then it is all hand grinding on a sheet of glass maintain parallel sides, with stops to clean the quartz and mount it in a holder to test it. The pencil mark will lower a crystal freq, but in a production unit this would not be allowed. The manufacture of this style crystal in this video, and HC6 size, was a fairly automated process in the later part of the 20th century, and even a CB radio company like Midland, had their own equipment to make crystals for their products. But, the last steps were all hands on to confirm actual success of the grind. Also, this style with the metal contact attached to the quartz took a different technique as compared to older mechanically assembled units that had contact plates separate from the quartz. This style is usually not adjustable, if you chip the edges, that can cause it to not oscillate, or oscillate erratically. I use a QRP Labs Crystal checker when grinding my own, but I use the FT243 style holders, much easier to deal with. With the QRP Labs unit, you can put one contact plate on the checker, the crystal, then the other plate with a metal probe attached to the other terminal of the checker, and push down and it will oscillate and give a freq reading on the display to see how close you are. The final check has to be made in the proper holder though. A side note. Crystal making was an art in the 1930s and the time before WW II the military leaned they had no source, all the companies in the US were basically 'Mom and Pop' and the one or two real companies only turned out a low quantity of crystals. The military was going to need millions. Crystals had an aging problem, and many crystals made for the military in FT241 style holders failed quickly, some failing before a new transmitter or receiver could be opened up new from the factory. That problem was worked on through out the war. Bell Labs had solved that issue in the 1930's, but were not in the crystal biz, they just studied quartz crystal issues to generate information. Since Bell was not in the crystal biz, nobody asked them to provide their solution to the crystal problem that was not fully resolved until almost the end of the war. The Crystals Go to War is a nice video, but the real story is in the Signal Corp trilogy of books, the primary crystal info being in 'The Emergency'. The 'Great War', WW I, the US learned that radio would play a big part in their future and quartz and bakelite were needed and hard to come by. After WW I, the US govt. started to stockpile quartz and bakelite, and they did so all the way until the Clinton regime when they were looking for cost cutting options. The govt. finally stopped the buying of these two elements. Always wondered what they did with all that Brazilian quartz and bakelite raw material they had collected for 70 years.
Used this method to check crystal filters found at a Hamfest. At least you can tell that it's not open. Also tap it to see if it's microphonic (thats bad).
The pencil mark on the xtal is how they "calibrate" or adjust the xtal to get it to the desired freq. Old timers used to use this trick to "move" xtals to a more desirable freq at times. In fact Rex W1REX at QRPme has a kit to allow you to grind and check your own xtals. You could probably make up one like it easy enough out of parts and microcomputers laying around the shack. 73
Long ago I noticed that if you put one wire of a crystal on the antenna of a super regenerative receiver then it will go quiet with no static at all when its tuned to the crystal frequency. (Super regenerative receivers typically make very loud noise when there is no signal being received.)
Sometimes you have to sacrifice an xtal. In the name of science. R.I.P. old quartz. A second stage would have been cheaper. But then it's no longer a one-transistor circuit. No risk, no fun.
Peter, I am sorry you have destroyed your crystal. I have destroyed a crystal myself in the past. It was one of these hc-49s tiny ones, like the ones you have and they were getting very hot and very chirpy like in your transmitter. But this was at a 0.5A to 1A of total current draw. The small crystals transfer easily the heat from the die to the external can and you can detect it more easily, but the larger ones like the one you cracked do not, so it is more difficult to detect. Lesson is, Do not use a crystal for quite long, if it sounds too chirpy with this transmitter. This means it is overheated inside. However, I have never destroyed a crystal that sounded chirp-free on the air. Cracking a crystal, seems believable, but removing the plating material from it, seems too extreme. I do not think this has been happened in your big crystal due to heating.
The RISE in noise is because you hit the series resonance of the Xtal. At Parallel there should be a dip. There is a SIMPLE regen. circuit with no coils but a Xtal from grid to ground for a single freq RX, The Hi impedance at parallel resonance acts a very high Q coil. Just carry rocks for your required QRG and shift channel pronto. 73 G3NBY.
Hi there vk3ye i've resently made a loop antenna but it does not work for my reciver since it only takes normal dipole or monopole. Is there a way we can convert the loop antenna output to make it a dipole/monopole output?
-- Interesting! I have a pile of old crystals that I am not sure are working or even what frequency they are oscillating on. I tried it on a long wire antenna while getting a lot of background noise and I noticed the signal level dropped by about 1-1/2 dB at resonance and much more on just off frequency. So I'm wondering if it also improves the signal-to-noise ratio on signals at that frequency. If it does, it may be a useful add-on for simple receivers matched with QRP transmitters using the commonly available 3.579 MHz TV color-burst crystals. So, some more experimenting to do. Now I'm also wondering how the arrangement passes harmonics of the fundamental frequency.
@@vk3ye oke sir,understoo.but if me using two xtal same frequency,one as transmitter and other as receiver,can it works sir???just like a walkie talkie.hehe
@@herupur1117 Crystals by themselves are useless without other parts to form a transmitter and receiver. A good radio theory book eg Ron Bertrand's Radio Theory Handbook will help you understand this further.
@@herupur1117 why not. you can see verious cw tx and rx using xtal based circuit. have a look at vu3inj.blogspot.com if any query put reply on blog will reply there.
If you want a complete do it yourself treatise on crystals, you will have to go back to the 1935 QST magazines, November and December if I recall. In those articles you will learn how to make a saw to cut raw crystal, the type of crystal to use and how to check the alignment of the quartz for the cut to make overtone or fundamental types, and the formula that approximates the thickness of crystal to cut for a particular frequency. Then it is all hand grinding on a sheet of glass maintain parallel sides, with stops to clean the quartz and mount it in a holder to test it. The pencil mark will lower a crystal freq, but in a production unit this would not be allowed. The manufacture of this style crystal in this video, and HC6 size, was a fairly automated process in the later part of the 20th century, and even a CB radio company like Midland, had their own equipment to make crystals for their products. But, the last steps were all hands on to confirm actual success of the grind. Also, this style with the metal contact attached to the quartz took a different technique as compared to older mechanically assembled units that had contact plates separate from the quartz. This style is usually not adjustable, if you chip the edges, that can cause it to not oscillate, or oscillate erratically. I use a QRP Labs Crystal checker when grinding my own, but I use the FT243 style holders, much easier to deal with. With the QRP Labs unit, you can put one contact plate on the checker, the crystal, then the other plate with a metal probe attached to the other terminal of the checker, and push down and it will oscillate and give a freq reading on the display to see how close you are. The final check has to be made in the proper holder though.
A side note. Crystal making was an art in the 1930s and the time before WW II the military leaned they had no source, all the companies in the US were basically 'Mom and Pop' and the one or two real companies only turned out a low quantity of crystals. The military was going to need millions. Crystals had an aging problem, and many crystals made for the military in FT241 style holders failed quickly, some failing before a new transmitter or receiver could be opened up new from the factory. That problem was worked on through out the war. Bell Labs had solved that issue in the 1930's, but were not in the crystal biz, they just studied quartz crystal issues to generate information. Since Bell was not in the crystal biz, nobody asked them to provide their solution to the crystal problem that was not fully resolved until almost the end of the war. The Crystals Go to War is a nice video, but the real story is in the Signal Corp trilogy of books, the primary crystal info being in 'The Emergency'.
The 'Great War', WW I, the US learned that radio would play a big part in their future and quartz and bakelite were needed and hard to come by. After WW I, the US govt. started to stockpile quartz and bakelite, and they did so all the way until the Clinton regime when they were looking for cost cutting options. The govt. finally stopped the buying of these two elements. Always wondered what they did with all that Brazilian quartz and bakelite raw material they had collected for 70 years.
Used this method to check crystal filters found at a Hamfest. At least you can tell that it's not open. Also tap it to see if it's microphonic (thats bad).
The pencil mark on the xtal is how they "calibrate" or adjust the xtal to get it to the desired freq. Old timers used to use this trick to "move" xtals to a more desirable freq at times. In fact Rex W1REX at QRPme has a kit to allow you to grind and check your own xtals. You could probably make up one like it easy enough out of parts and microcomputers laying around the shack. 73
Long ago I noticed that if you put one wire of a crystal on the antenna of a super regenerative receiver then it will go quiet with no static at all when its tuned to the crystal frequency. (Super regenerative receivers typically make very loud noise when there is no signal being received.)
Brillant! Thank you for sharing.
I'm always learning something from you... Thanks.
I love it. Quick and dirty, and it works.
Sometimes you have to sacrifice an xtal. In the name of science.
R.I.P. old quartz.
A second stage would have been cheaper. But then it's no longer a one-transistor circuit.
No risk, no fun.
Peter, I am sorry you have destroyed your crystal. I have destroyed a crystal myself in the past. It was one of these hc-49s tiny ones, like the ones you have and they were getting very hot and very chirpy like in your transmitter. But this was at a 0.5A to 1A of total current draw. The small crystals transfer easily the heat from the die to the external can and you can detect it more easily, but the larger ones like the one you cracked do not, so it is more difficult to detect. Lesson is, Do not use a crystal for quite long, if it sounds too chirpy with this transmitter. This means it is overheated inside.
However, I have never destroyed a crystal that sounded chirp-free on the air. Cracking a crystal, seems believable, but removing the plating material from it, seems too extreme. I do not think this has been happened in your big crystal due to heating.
Really cool! Gonna try this thanks!
I love it good
Keep uploading videos like this
How much power can this Xtal handle?
Yes
The RISE in noise is because you hit the series resonance of the Xtal. At Parallel there should
be a dip.
There is a SIMPLE regen. circuit with no coils but a Xtal from grid to ground for a single freq
RX, The Hi impedance at parallel resonance acts a very high Q coil. Just carry rocks for your required QRG and shift channel pronto.
73 G3NBY.
Hi there vk3ye i've resently made a loop antenna but it does not work for my reciver since it only takes normal dipole or monopole. Is there a way we can convert the loop antenna output to make it a dipole/monopole output?
-- Interesting! I have a pile of old crystals that I am not sure are working or even what frequency they are oscillating on.
I tried it on a long wire antenna while getting a lot of background noise and I noticed the signal level dropped by about 1-1/2 dB at resonance and much more on just off frequency. So I'm wondering if it also improves the signal-to-noise ratio on signals at that frequency. If it does, it may be a useful add-on for simple receivers matched with QRP transmitters using the commonly available 3.579 MHz TV color-burst crystals.
So, some more experimenting to do. Now I'm also wondering how the arrangement passes harmonics of the fundamental frequency.
Sir can we using a xtal as a receiver??
A crystal is just one radio component. A receiver needs many electronic components to work.
@@vk3ye oke sir,understoo.but if me using two xtal same frequency,one as transmitter and other as receiver,can it works sir???just like a walkie talkie.hehe
@@herupur1117 Crystals by themselves are useless without other parts to form a transmitter and receiver. A good radio theory book eg Ron Bertrand's Radio Theory Handbook will help you understand this further.
@@herupur1117 why not. you can see verious cw tx and rx using xtal based circuit. have a look at vu3inj.blogspot.com if any query put reply on blog will reply there.
Typical the pencil marks are normal.