Some of the greatest ideas are the simple ones, that was fantastic Nick - as we were saying last night as well, analogue stuff is so much easier to see what's going on. This glue stick PTO is wonderfully visual!
Another good video, thanks Nick! I did see this on solder smoke and it was great to see your version. In the 80s there was electronic surplus company called Bull and Son who made kits from items they had bought wholesale. The first receiver I made was one of their kits. It used a coil wound round a pencil former to make an air coil. The tuning was done by a piece of ferrite rod stuck to a string, which the tuning knob raised or lowered into the coil. It worked a treat and I guess was a similar principle.😀
Thanks so much. Yes, it is a surprisingly common idea when you dig into it. I think it's just that it has not had too much attention of late ... until now! Thanks for watching and commenting as always. 73 Nick
Excellent Nick! And the irony ... removing all the glue to then use two different glues, double sided tape, and zip ties to hold things in place ... :)
Nick, my goal is to do what you're doing in the homebrew realm. I started out building Colpitts and Clapp oscillators. The Hartley has one capacitor and two coils. I wonder if it would help with stability to throw in a second fixed coil. My Colpitts seem very stable even on a breadboard down in the 1.2MHz range. Gotta try this!
Hi Mark, I actually started out on my own homebrew journey by building analogue VFOs. I didn't have great success to be honest but I had a lot of fun. It is actually not a trivial thing to build but it can be done and done very well. It is something that I have considered revisiting now I have a better idea of which end of the soldering iron to pick up! Keep up the great work. Bill N2CQR would be a great person for you to contact - he has a real passion for analogue VFOs and won't go near an Si5351! 73, Nick
You can just use ferrous washers, glued together. However, if you want precise tuning and mechanical 'memories', you could use an old MW/LW car radio as they use PTO tuning too. G7VFY
Nice project, I've been playing with gluesticks as tuning mechanisms for a while now but with ferrites harvested from discarded shop security tags. I've also been toying with the idea of making variable capacitors (trombone? Piston? I dunno) from them with slug tape. Strikes me that you could have built the circuit without the copper clad PCB if the tin is solderable
Thanks Clint. Well done on your own glue stick inductors. I too have played around with building a variable capacitor piston-style with two metal tubes of different diameter. It worked but would have needed more mechanical refinement to make it practical. The metal tin I used is not great to solder to. You can if you scratch it up a bit first but it was just easier to build on FR4 and stick it in. Thanks very much for watching and commenting. 73 Nick
I made one just about exactly like yours and the inductance was remarkably close. Mine was 6.566uH to 7.542uH measured with my NanoVNA. I'll initially put this one in a 20m DC receiver, but will eventually add switchable caps to make the receiver multiband. Could you stack different winds on the same glue stick as well to cover multibands or would the inductors have some mutual effect? Edit...mine drifts pretty badly at first. It could be that I'm running the oscillator from an unregulated 9v battery. I will try adding a 5v regulator and maybe insulating the PTO.
Congratulations! As to stacking the windings I've not actually tried that. It would be worth you having a go and reporting back if you are able please. If it IS possible then that will greatly simply using the Glue-Stick PTO in a multi band rig. Good question and interesting idea! Thanks very much. 73, Nick
Great video nick been learning some rig homebrew myself recently, love those pads we’re do you get those from btw? Also if I was to make RFC choke for say like a old VK200 style one what would you recommend?
Thanks Jon. The 'Me Pads' come from Club Sales at the GQRP Club but you can get them elsewhere (www.qrpme.com). I don't have any experience of the VK200 itself but if you google 'VK200 ferrites' you should find some. To be honest the finished chokes are so cheap it is hardly worth rolling your own but if you want to then good for you! All the best with your own building. 73 Nick
@@M0NTVHomebrewing thanks 😊 nick i must try a little harder with the searching some parts can be so tricky to find these days especially the good stuff x
@@jonhoyles714 If you can't find any Me pads, grab a piece of 0.9mm (or less) single sided FR4 PCB and just chop it up into whatever sized pads you want. That works just as well. Andy
The one problem you migh have with a glestick is the backlash from the slop in the plastic parts. One thing to try is cutting some sott foam inrto discs that fit into the end of the glue stick tube. Wiith te end cap on this should providee enough back pressure on the tuning slug to reduce or elminate the backlash. Probably have to play with type of foam, and how much you pack into the tube.
Thanks DuWayne you're absolutely right. The first one I built was great - very little backlash and comfortably firm turning but this latest one is not quite so tight. I'll have a play! Thanks again. 73 Nick
@@M0NTVHomebrewing You will prob. be fighting a loosing battle as the production tolerance on such things tend be very "loose" so it will be pot luck if you get a "tight" fit or one with a load of backlash. Apart from making an entirely better engineered version, you could improve things by replacing the existing threaded rod with a Nut and bolt. Use a nylon bolt M4 or M5 as a replacement. Glue the head of the bolt into the "knob" end of the glue tube, and the M4 or M5 nut into the centre of the grey carriage. That will give a consistent operation. Use two grey carriages with a spring between them and most of the remaining backlash will be removed. Andy
Thanks Andy. I should really have experimented with the physical construction of the turning mechanism before I'd built the coil on it and enclosed it in a metal tin! The next one will be better!!! Thanks again for the ideas. 73 Nick
Hi Kevin, I guess it depends on how you look at it. For me, the problem is how to build a stable analogue VFO: one solution is to build a PTO. But the problem with a PTO is that it requires a variable inductor: one solution is to use a glue stick as a former. I suppose my interest in it is in encouraging people to build radios e.g. a Direct Conversion Receiver. For some the idea of programming a microcontroller and using an Si5351 (my favourite method) is just a step too far in complexity. So I'm interested in anything which will help folk to gets hand-on and start building. It's just an experiment but for me that's the fun of ham radio. 73 Nick
Have been using deodorant cartidges of a wll known mark troughout the world it sugest spice .It has a rising mechanism provided with a worm type screw suitable for this purpose.Aha.I been using a guitar tuning knob for a reducer in displacement of the shaft in a gear ratio of 1:16 aprox.Compliments!
All those harmonics are telling you this oscillator is clipping. You need to look at the output signal shape, it should be a sine wave, and the less departure from a sine, the purity will increase. This oscillator is too dirty to use as is.
You raise an interesting question! You may be right about the clipping but I disagree with it being too dirty to use. Have you ever examined the output from an Si5351 module? It is a square wave which has harmonics all over the spectrum. I sometimes use a low pass filter on it but plenty of people feed this square wave directly into the mixer. Some even argue that you SHOULD feed a diode ring mixer with a square wave because the diodes turn on more quickly. Personally I prefer a cleaner more sinusoidal input as it results in fewer inter-modulation products. So whilst I tend to side with you on preferring a sine output there are many homebrew radios out there that seem to cope pretty well with harmonics going into the mixer. As I said ... it is an interesting one! 73, Nick
Wrong coil, too tight, they should be winded loosely, and even progressively spread by the end. Wrong mechanical basement for inner ferrite core. The best mechanically stable and precise thing for this is micrometers. Next time if will build PTO don't forget to sound this tested and build PTO from comment sections ) And better use fets for oscillators. You can find builded PTO with old Ten Tec PTO as for inspiration and reference.
Thanks for your comments. The whole Glue Stick PTO is by very nature an experimental project. It is not really a matter of a "wrong coil' or a "wrong mechanical basement" - simply that I chose to build mine in a different way than you would. This one was actually the third one I built and each time I changed things around to see what difference it makes. This for me is the very nature of ham radio homebrew - experimentation. Incidentally the oscillator DOES use a FET and the design comes straight from Ashhar Farhan's Daylight Again transceiver. Thanks again. 73 Nick
Bill mentioned you on Solder Smoke and I had to check this out. Now I have to watch a lot more of your videos. Thanks.
Thanks very much Ron. 73 Nick
Some of the greatest ideas are the simple ones, that was fantastic Nick - as we were saying last night as well, analogue stuff is so much easier to see what's going on. This glue stick PTO is wonderfully visual!
Thanks Al! Good to see you last night as well. Hope you've had a good day off :)
Another good video, thanks Nick! I did see this on solder smoke and it was great to see your version.
In the 80s there was electronic surplus company called Bull and Son who made kits from items they had bought wholesale. The first receiver I made was one of their kits. It used a coil wound round a pencil former to make an air coil. The tuning was done by a piece of ferrite rod stuck to a string, which the tuning knob raised or lowered into the coil.
It worked a treat and I guess was a similar principle.😀
Thanks so much. Yes, it is a surprisingly common idea when you dig into it. I think it's just that it has not had too much attention of late ... until now! Thanks for watching and commenting as always. 73 Nick
Might also be good in a small QRP Pi match for portable use... Good idea Nick, thanks for bringing it to us!
You are welcome!
Great video Nick. With the winter coming, I'm going to start harvesting glue sticks 🙂
Thanks Lex. It's a fun little project. All the best in your own experimenting. 73 Nick
Excellent Nick! And the irony ... removing all the glue to then use two different glues, double sided tape, and zip ties to hold things in place ... :)
You're not wrong Neville! Thanks for watching :)
Nick, my goal is to do what you're doing in the homebrew realm. I started out building Colpitts and Clapp oscillators. The Hartley has one capacitor and two coils. I wonder if it would help with stability to throw in a second fixed coil. My Colpitts seem very stable even on a breadboard down in the 1.2MHz range. Gotta try this!
Hi Mark, I actually started out on my own homebrew journey by building analogue VFOs. I didn't have great success to be honest but I had a lot of fun. It is actually not a trivial thing to build but it can be done and done very well. It is something that I have considered revisiting now I have a better idea of which end of the soldering iron to pick up! Keep up the great work. Bill N2CQR would be a great person for you to contact - he has a real passion for analogue VFOs and won't go near an Si5351! 73, Nick
You can just use ferrous washers, glued together. However, if you want precise tuning and mechanical 'memories', you could use an old MW/LW car radio as they use PTO tuning too. G7VFY
Thanks Stephen. It's the first time I've ever really thought about PTOs but there is plenty of room for experimentation. 73 Nick
Nice project, I've been playing with gluesticks as tuning mechanisms for a while now but with ferrites harvested from discarded shop security tags.
I've also been toying with the idea of making variable capacitors (trombone? Piston? I dunno) from them with slug tape.
Strikes me that you could have built the circuit without the copper clad PCB if the tin is solderable
Thanks Clint. Well done on your own glue stick inductors. I too have played around with building a variable capacitor piston-style with two metal tubes of different diameter. It worked but would have needed more mechanical refinement to make it practical.
The metal tin I used is not great to solder to. You can if you scratch it up a bit first but it was just easier to build on FR4 and stick it in. Thanks very much for watching and commenting. 73 Nick
I made one just about exactly like yours and the inductance was remarkably close. Mine was 6.566uH to 7.542uH measured with my NanoVNA. I'll initially put this one in a 20m DC receiver, but will eventually add switchable caps to make the receiver multiband. Could you stack different winds on the same glue stick as well to cover multibands or would the inductors have some mutual effect? Edit...mine drifts pretty badly at first. It could be that I'm running the oscillator from an unregulated 9v battery. I will try adding a 5v regulator and maybe insulating the PTO.
Congratulations! As to stacking the windings I've not actually tried that. It would be worth you having a go and reporting back if you are able please. If it IS possible then that will greatly simply using the Glue-Stick PTO in a multi band rig. Good question and interesting idea! Thanks very much. 73, Nick
Great video nick been learning some rig homebrew myself recently, love those pads we’re do you get those from btw? Also if I was to make RFC choke for say like a old VK200 style one what would you recommend?
Thanks Jon. The 'Me Pads' come from Club Sales at the GQRP Club but you can get them elsewhere (www.qrpme.com). I don't have any experience of the VK200 itself but if you google 'VK200 ferrites' you should find some. To be honest the finished chokes are so cheap it is hardly worth rolling your own but if you want to then good for you! All the best with your own building. 73 Nick
@@M0NTVHomebrewing thanks 😊 nick i must try a little harder with the searching some parts can be so tricky to find these days especially the good stuff x
@@jonhoyles714 If you can't find any Me pads, grab a piece of 0.9mm (or less) single sided FR4 PCB and just chop it up into whatever sized pads you want. That works just as well.
Andy
@@andye2005 thanks Andy yeah that’s what I usually do chop bits up for pads 👍
Also used in older TenTec gear.
I was wondering "wouldn't that melt the glue" until I saw you replaced the glue with ferrite.
The one problem you migh have with a glestick is the backlash from the slop in the plastic parts. One thing to try is cutting some sott foam inrto discs that fit into the end of the glue stick tube. Wiith te end cap on this should providee enough back pressure on the tuning slug to reduce or elminate the backlash. Probably have to play with type of foam, and how much you pack into the tube.
Thanks DuWayne you're absolutely right. The first one I built was great - very little backlash and comfortably firm turning but this latest one is not quite so tight. I'll have a play! Thanks again. 73 Nick
@@M0NTVHomebrewing You will prob. be fighting a loosing battle as the production tolerance on such things tend be very "loose" so it will be pot luck if you get a "tight" fit or one with a load of backlash.
Apart from making an entirely better engineered version, you could improve things by replacing the existing threaded rod with a Nut and bolt. Use a nylon bolt M4 or M5 as a replacement. Glue the head of the bolt into the "knob" end of the glue tube, and the M4 or M5 nut into the centre of the grey carriage. That will give a consistent operation.
Use two grey carriages with a spring between them and most of the remaining backlash will be removed.
Andy
Thanks Andy. I should really have experimented with the physical construction of the turning mechanism before I'd built the coil on it and enclosed it in a metal tin! The next one will be better!!! Thanks again for the ideas. 73 Nick
Next use a FRANKLIN OSCILLATOR as PTO!
Hi! Not tried one of those. Thanks. 73, Nick
👍💕
Cheers Alex!
That’s a solution in search of a problem if I’ve ever seen one.
Hi Kevin, I guess it depends on how you look at it. For me, the problem is how to build a stable analogue VFO: one solution is to build a PTO. But the problem with a PTO is that it requires a variable inductor: one solution is to use a glue stick as a former. I suppose my interest in it is in encouraging people to build radios e.g. a Direct Conversion Receiver. For some the idea of programming a microcontroller and using an Si5351 (my favourite method) is just a step too far in complexity. So I'm interested in anything which will help folk to gets hand-on and start building. It's just an experiment but for me that's the fun of ham radio. 73 Nick
Have been using deodorant cartidges of a wll known mark troughout the world it sugest spice .It has a rising mechanism provided with a worm type screw suitable for this purpose.Aha.I been using a guitar tuning knob for a reducer in displacement of the shaft in a gear ratio of 1:16 aprox.Compliments!
Thanks very much. Your own creations sound interesting. There are so many different ways of doing this! 73, Nick
All those harmonics are telling you this oscillator is clipping. You need to look at the output signal shape, it should be a sine wave, and the less departure from a sine, the purity will increase. This oscillator is too dirty to use as is.
You raise an interesting question! You may be right about the clipping but I disagree with it being too dirty to use. Have you ever examined the output from an Si5351 module? It is a square wave which has harmonics all over the spectrum. I sometimes use a low pass filter on it but plenty of people feed this square wave directly into the mixer. Some even argue that you SHOULD feed a diode ring mixer with a square wave because the diodes turn on more quickly. Personally I prefer a cleaner more sinusoidal input as it results in fewer inter-modulation products. So whilst I tend to side with you on preferring a sine output there are many homebrew radios out there that seem to cope pretty well with harmonics going into the mixer. As I said ... it is an interesting one! 73, Nick
Wrong coil, too tight, they should be winded loosely, and even progressively spread by the end. Wrong mechanical basement for inner ferrite core. The best mechanically stable and precise thing for this is micrometers. Next time if will build PTO don't forget to sound this tested and build PTO from comment sections ) And better use fets for oscillators. You can find builded PTO with old Ten Tec PTO as for inspiration and reference.
And how is made. ua-cam.com/video/RMmS0wBam2g/v-deo.html
Thanks for your comments. The whole Glue Stick PTO is by very nature an experimental project. It is not really a matter of a "wrong coil' or a "wrong mechanical basement" - simply that I chose to build mine in a different way than you would. This one was actually the third one I built and each time I changed things around to see what difference it makes. This for me is the very nature of ham radio homebrew - experimentation. Incidentally the oscillator DOES use a FET and the design comes straight from Ashhar Farhan's Daylight Again transceiver. Thanks again. 73 Nick