Thank you for showing us making coils that can be tuned to the desired frequencies and then checking the Q of the coils. BTW: Mike one of your earlier videos on the Q-meter you restored, inspired me to buy a Q-meter, I obtained a Heathkit QM-1 at an Antique Radio show last Sept.
4:05 Definitely! For one thing, like with a Q multiplier, the regen feedback varies the selectivity. Depending on whether you're receiving AM, SSB, or CW, and also, any QRM, you want to adjust that. And with a maximum peak, they tend to be "touchy," and require frequent tweaking.
In the article, they suggest that the regen be set below critical and both the detector coil and pot be left alone, and you use the BFO for CW and SSB.
@@MIKROWAVE1Is the regen control needed to substitute the RF gain control? There isn't the RF gain pot at all, often on 80m band the signals can be really strong.
@@JuhaK71 The Detector is never actually put into oscillation in this circuit. Everything happens below critical. So the control is actually more of an RF gain control in my observations so far with the set.
This is awesome. Will be very pleased to see this one get working. I hope to run into old homebrew receivers at hamfests, bring em home and sort em out. This sort of video also makes me want to find one of those grid dip thingummies at a ham fest.
Sometimes you can find ham project builds from the magazines or the Handbooks. I found a perfect build of the 3 Band Novice transmitter from the early 1960's with the 6DQ6, and it restored nicely.
Impressive! I would not have expected the air wound coil to have such a high Q. Really enjoying this series. With homebrewing, the problems begin when the homebrewer starts drilling holes. Just kidding!
Thanks Mike. I would always believe an air-core coil had a higher Q than a ferrite toroid. That's why I have some plastic toroids in my parts bins for making high-Q coils that fit into tight places in my projects without losing their Q, though there are always Q vs size trade-offs between air and ferrite or powdered iron. BTW, the video cut off in mid-word.
So.....I finally went out and bought 25x T50-6's, 25x T50-43's and it turns out I already had some T50-2's in my junk box. I'm all prepared to tackle the "terrible toroid" phobia, just to find out that I could wind as "good" a coil on a pvc pipe! I wonder how the Q would be with 43 turns on one of those other mixes? Time to rewind, then time to unwind (ahhhhh). This looks like it's an awesome receiver. I look forward to see how it comes out! Take care and 73.
The 43s are fine for transformers, but will not provide a high Q in the tuned coil in this frequency range. The T50-6 will work but will require more turns. I like these up higher from 15m to 6m.
I'm glad you measured the Q of those coils, and I'm somewhat surprised the PVC coil did that well. PVC is not a great dielectric material for coil forms, plus the insulation on the wire is not that great either. Doug Demaw has a good article on building high Q coils, and PVC was pretty low on the list for coil form material. It would be interesting to see what the normalized self-resonance point is between the B&W coil and your PVC coil. I've seen other Q measurements of B&W coils in the past and I seem to remember the Q being a lot higher than what you were measuring - like 200-300 - but hey, it-is-what-it-is, and I might not be remembering all that well either - LOL. The toroid, well, reduced wire length plays a large factor there to increase Q - but you have to consider the core loss which would lower the Q.
It surprised me too. In the next video I cover the three IF inductors. Mixer, Det and BFO...The 2 MHz inductors with simple powdered iron slugs have a huge disparity in Q from ordinary scramble wound enamel wire compared to even the most basic Litz wire.
The 1967 handbook had a dual band converter for 80 and 40 that could be used in front of a BCB or 160 meter receiver that was a band image converter. Think you meant a 480vct pwr xfmr. I'm not surprised that the air wound coil has a higher Q. The powdered iron core adds more loss to the coil than the reduction in the amount of wire would add. Even if both were wound with the same gauge wire, the air would coil might have a higher Q. However, the toroid is much smaller in size, and if we were building a solid state version, we would gladly accept the lower Q to have a smaller radio, and we could add a third tuned stage to the front end to make up for the lower Q and STILL have a smaller radio.
The 480V was with the voltage drop of the 5Y3. With Silicon this could be 350 to 375 CT for Cap Input and 420-440 CT for Choke input. But I really believe that this circuit would function OK if you end up with 180VDC to 300 VDC without much complaint.
Hello all, by sheer coincidence, I actually sent Dave Newkirk an email about Tri-tets and regenerative receivers in general a few days ago. Sadly so far no answer, and I'm not sure if anybody knows whether he is still active or not? Regards, Thomas
You see whole sets show up at hamfesters now. The fact that they are scanned and available on line, means you really need to seek a home for them. Maybe one of the subscribers would be interested.
Hi Mike. I remember the mark one circuit but not the mark two version. Back then I couldn't afford the xtal so I decided to design my own radio but it was a superhet. Best of luck with it. Paul Thailand. De HS0ZLQ, G0MIH
Thank you Mike for regenerating such interesting articles.
Many viewers saw these projects in the Handbook and in magazines as young people, and never got to build or experience them.
Thank you for showing us making coils that can be tuned to the desired frequencies and then checking the Q of the coils. BTW: Mike one of your earlier videos on the Q-meter you restored, inspired me to buy a Q-meter, I obtained a Heathkit QM-1 at an Antique Radio show last Sept.
Wow that's great about finding Q meter!
4:05 Definitely! For one thing, like with a Q multiplier, the regen feedback varies the selectivity. Depending on whether you're receiving AM, SSB, or CW, and also, any QRM, you want to adjust that. And with a maximum peak, they tend to be "touchy," and require frequent tweaking.
In the article, they suggest that the regen be set below critical and both the detector coil and pot be left alone, and you use the BFO for CW and SSB.
@@MIKROWAVE1Is the regen control needed to substitute the RF gain control? There isn't the RF gain pot at all, often on 80m band the signals can be really strong.
@@JuhaK71 The Detector is never actually put into oscillation in this circuit. Everything happens below critical. So the control is actually more of an RF gain control in my observations so far with the set.
This is awesome. Will be very pleased to see this one get working. I hope to run into old homebrew receivers at hamfests, bring em home and sort em out. This sort of video also makes me want to find one of those grid dip thingummies at a ham fest.
Sometimes you can find ham project builds from the magazines or the Handbooks. I found a perfect build of the 3 Band Novice transmitter from the early 1960's with the 6DQ6, and it restored nicely.
Impressive! I would not have expected the air wound coil to have such a high Q. Really enjoying this series.
With homebrewing, the problems begin when the homebrewer starts drilling holes. Just kidding!
It gets more interesting when I get to the 1.7 (2 MHz) inductors in the next session.
18:52 Amazing ancient device . But still active!)))
Sometimes a simple device is faster!
Thanks Mike. I would always believe an air-core coil had a higher Q than a ferrite toroid. That's why I have some plastic toroids in my parts bins for making high-Q coils that fit into tight places in my projects without losing their Q, though there are always Q vs size trade-offs between air and ferrite or powdered iron. BTW, the video cut off in mid-word.
I am glad you are getting into the nuts and bolts. That mid-word cut off is an editor's error, unfortunately.
So.....I finally went out and bought 25x T50-6's, 25x T50-43's and it turns out I already had some T50-2's in my junk box. I'm all prepared to tackle the "terrible toroid" phobia, just to find out that I could wind as "good" a coil on a pvc pipe! I wonder how the Q would be with 43 turns on one of those other mixes? Time to rewind, then time to unwind (ahhhhh). This looks like it's an awesome receiver. I look forward to see how it comes out!
Take care and 73.
The 43s are fine for transformers, but will not provide a high Q in the tuned coil in this frequency range. The T50-6 will work but will require more turns. I like these up higher from 15m to 6m.
@@MIKROWAVE1 Nothing beats building and trying. A Q meter should be in my future tool box. Thanks and take care.
I'm glad you measured the Q of those coils, and I'm somewhat surprised the PVC coil did that well. PVC is not a great dielectric material for coil forms, plus the insulation on the wire is not that great either. Doug Demaw has a good article on building high Q coils, and PVC was pretty low on the list for coil form material. It would be interesting to see what the normalized self-resonance point is between the B&W coil and your PVC coil. I've seen other Q measurements of B&W coils in the past and I seem to remember the Q being a lot higher than what you were measuring - like 200-300 - but hey, it-is-what-it-is, and I might not be remembering all that well either - LOL. The toroid, well, reduced wire length plays a large factor there to increase Q - but you have to consider the core loss which would lower the Q.
It surprised me too. In the next video I cover the three IF inductors. Mixer, Det and BFO...The 2 MHz inductors with simple powdered iron slugs have a huge disparity in Q from ordinary scramble wound enamel wire compared to even the most basic Litz wire.
The 1967 handbook had a dual band converter for 80 and 40 that could be used in front of a BCB or 160 meter receiver that was a band image converter.
Think you meant a 480vct pwr xfmr.
I'm not surprised that the air wound coil has a higher Q. The powdered iron core adds more loss to the coil than the reduction in the amount of wire would add. Even if both were wound with the same gauge wire, the air would coil might have a higher Q. However, the toroid is much smaller in size, and if we were building a solid state version, we would gladly accept the lower Q to have a smaller radio, and we could add a third tuned stage to the front end to make up for the lower Q and STILL have a smaller radio.
The 480V was with the voltage drop of the 5Y3. With Silicon this could be 350 to 375 CT for Cap Input and 420-440 CT for Choke input. But I really believe that this circuit would function OK if you end up with 180VDC to 300 VDC without much complaint.
Great Information!
We are on our way to a receiver that even the 70 year old kids can build.
Hi mike where did you get the chassis from i would like to build this radio
I got it off Amazon. www.amazon.com/BUD-Industries-AC-424-Aluminum-Chassis/dp/B005T58WWE
If there is a regenerative detector in the circuit, can you eliminate the BFO?
Technically yes! But with a reduction in stability and you would have to add a tuning control.
👍Thank you sir.
Thanks for watching the series!
Hello all,
by sheer coincidence, I actually sent Dave Newkirk an email about Tri-tets and regenerative receivers in general a few days ago. Sadly so far no answer, and I'm not sure if anybody knows whether he is still active or not?
Regards,
Thomas
Dunno, but I can ask around.
I have all QST magazines from 1946 to 1989. I need to leave these to somebody.
You see whole sets show up at hamfesters now. The fact that they are scanned and available on line, means you really need to seek a home for them. Maybe one of the subscribers would be interested.
@@MIKROWAVE1 If I had your address I would send you a few
Tubes and toroids? Heresy! 😂
Yes! String me up with Litz wire! That Is why I offered both as a solution.
Hi Mike. I remember the mark one circuit but not the mark two version. Back then I couldn't afford the xtal so I decided to design my own radio but it was a superhet.
Best of luck with it.
Paul Thailand.
De HS0ZLQ, G0MIH
My first superhet used a TOKO ceramic filter out of an AM radio. Pretty broad! But I used it on CW.
All of your video is now in auto dubbing mode, in very bad french, with a robot voice. I don't understand why you did that, but I can't understand.
Great Information !
As always - Thanks for watching Jack!