Very impressed an interesting exercise. Back in 1972 my first training course as a radio tech was to repair and re-align RA17. Curious if you have been able to compare the image rej/cross-mod/stab perf etc etc against the valved version.
Dear Dayle; Very nice to read your plans and efforts to create your own FRG7, tubes are surly interesting. Afterwards you will be very lucky with the results. Although the original design used a free running (last) oscillator - because of the low frequency - you still want to improve on that. Using tubes in st of a TBA120, will require at least 3 tubes and filters. You can also have a look at the Huff Puff stabilizer design. BUT that's also not easy to accomplice with tubes. THAT was the reason voor the orig Racal design. In those day's it was not simpel to build a phase-loop-loop, it requires several 19 inch cabinets. Use of crystal's did help, but you needed a lat, if you want to cover the hole range from 0 to 30-50MHz. Racals RA17 was a solution and uses only 1 crystal. See my other video about this design; th-cam.com/video/oE3rIZ8k-0o/w-d-xo.html It was born, because the Racal company looses the permission to copy the Collins receiver, there original plan. Afterwards the Racal AR17 was faster than the Collins. Sensitivity etc they are equile. But with al the frequency's that are generated inside the Racal, it's a miracle that there are no extra tones or cross-modulations. Partly due, to the enormous chassis that consist of two parts. To get rid of the last interference. Sorry for the bad Englice....
I was very interested in this, as I have "upgraded" an old Wadley Loop FRG7 to using vacuum tubes, the complete opposite to what you have done. Like yourself, I have tried very hard to use the existing dials and controls. And, thank you for showing the VFO stabilising circuit, this is also a very interesting concept, do you have an idea how many vacuum tubes it would take to emulate a TBA120?😀
I agree with Allan Watson....we get to the IMPORTANT part of the video (what does the product detector sound like ?), only to have music in the way ???
Excellent work Theo, thanks for sharing. Love the LED readout. I have a Telefunken receiver E863/KW2 which is excellent radio but I would like to change the nixies readouts with led, I wonder if you have done anything like that or give us some pointers, best
Yep, Telefunken made wonderful and good radios. Chance the Nixies voor LED's seems not so difficult, but a lat of work. Finding the wright format of LED's and after that, drive them individually by IC's (maybe i have them here???) Most important is to subtract the IF frequency. Probl it is already be done by the exciting electronics. If you have the schematics i wil look in to that.
A question if I may? Instead of your delay line frequency "lock" for the Tuneable IF, how would "remembering " say the last 2 digits of the frequency counter in a Cmos latch, and comparing it with successive readings? Of course the latch would require refreshing periodically to allow smooth tuning. This may be a simpler circuit, and easier for me than sourcing a delay line given PAL TV is pretty much obsolete..... here in NZ at least.? Thank you.
Fantastic job...both mechanic and electronic. BRAVO!!!!!
What a way to save an old beyond saving receiver. Way to go!
Very nice work. I would have no issues over the "authenticity" of such a well-redesigned receiver!
Thanks!!!
Beutiful..like Frankestein
Very impressed an interesting exercise. Back in 1972 my first training course as a radio tech was to repair and re-align RA17. Curious if you have been able to compare the image rej/cross-mod/stab perf etc etc against the valved version.
It was not easy, i can tell you. Took a long time, but was very nice to do...! That's the radio-hobby for me!
Beautiful work!!!
Dear Dayle; Very nice to read your plans and efforts to create your own FRG7, tubes are surly interesting. Afterwards you will be very lucky with the results. Although the original design used a free running (last) oscillator - because of the low frequency - you still want to improve on that. Using tubes in st of a TBA120, will require at least 3 tubes and filters. You can also have a look at the Huff Puff stabilizer design. BUT that's also not easy to accomplice with tubes. THAT was the reason voor the orig Racal design. In those day's it was not simpel to build a phase-loop-loop, it requires several 19 inch cabinets. Use of crystal's did help, but you needed a lat, if you want to cover the hole range from 0 to 30-50MHz. Racals RA17 was a solution and uses only 1 crystal. See my other video about this design; th-cam.com/video/oE3rIZ8k-0o/w-d-xo.html It was born, because the Racal company looses the permission to copy the Collins receiver, there original plan. Afterwards the Racal AR17 was faster than the Collins. Sensitivity etc they are equile. But with al the frequency's that are generated inside the Racal, it's a miracle that there are no extra tones or cross-modulations. Partly due, to the enormous chassis that consist of two parts. To get rid of the last interference. Sorry for the bad Englice....
klopotliwa praca respekt
This an amazing art work!
Thanks !!!
I was very interested in this, as I have "upgraded" an old Wadley Loop FRG7 to using vacuum tubes, the complete opposite to what you have done. Like yourself, I have tried very hard to use the existing dials and controls. And, thank you for showing the VFO stabilising circuit, this is also a very interesting concept, do you have an idea how many vacuum tubes it would take to emulate a TBA120?😀
See above
I agree with Allan Watson....we get to the IMPORTANT part of the video (what does the product detector sound like ?), only to have music in the way ???
Thanks for the reaction and advice...
Excellent work Theo, thanks for sharing. Love the LED readout. I have a Telefunken receiver E863/KW2 which is excellent radio but I would like to change the nixies readouts with led, I wonder if you have done anything like that or give us some pointers, best
Yep, Telefunken made wonderful and good radios. Chance the Nixies voor LED's seems not so difficult, but a lat of work. Finding the wright format of LED's and after that, drive them individually by IC's (maybe i have them here???) Most important is to subtract the IF frequency. Probl it is already be done by the exciting electronics. If you have the schematics i wil look in to that.
Very interesting video but the "music" is very distracting, especially near the end when you are tuning in some speech signals.
Thanks for the response and sorry you find the music distracting. It's there, to make it more 'view-e-bel'. My voice is not all that attractive.
A remotely similar Vfo circuit with a Tv delay line is used in the Braun se402
A question if I may? Instead of your delay line frequency "lock" for the Tuneable IF, how would "remembering " say the last 2 digits of the frequency counter in a Cmos latch, and comparing it with successive readings? Of course the latch would require refreshing periodically to allow smooth tuning. This may be a simpler circuit, and easier for me than sourcing a delay line given PAL TV is pretty much obsolete..... here in NZ at least.? Thank you.
See above
Hey, may be are a fan of Charles Smith (KV4JT) ? Fantastic job 🎩🎩🎩
No i did not, but now i know, looked it up en thanks voor de tip. He has also films on YT. Thanks again!
Bet it took at least a year.
Yep! off and on, you know how it works...
Ha! You are crazy, but the good kind,... Nice work. I am sure that many hours were consumed.
I encourage you to finish the panel.
Thanx....!