1 Tube regen

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1 Tube regen

Post by SWsenior on Wed Jan 08, 2014 3:31 pm

I am new to regens but have made lots of crystal radios.  So to say the least, my knowledge is limited.  I just got a regen built with the help of a young guy who was visiting area relatives.

I have a few questions to ask about components.

On a coil, the schematic may show X amount of turns on a X diameter form. If I use a different size form and wire size, (but using Professor Coyle) I can determine that the Q comes out to the same as what the schematic calls for will it still be ok to go that route?

How critical are the values of capacitors and resistors? I have been able to find info on resistors and capacitors on how to use them in parallel or series.

Will it make a difference where some of the parts ( coil, variable capacitor, battery connections, antenna and ground) are placed?

Also, I have searched online for sites that have instructions for this sort of info, but am unable to find anything that really helps. I have seen some videos (youtube) but they really haven't given me any help. Any links to check out?

Thanks for your time!

SW

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Re: 1 Tube regen

Post by Dr. Radio on Wed Jan 08, 2014 6:40 pm

SWsenior wrote:I am new to regens but have made lots of crystal radios.  So to say the least, my knowledge is limited.  I just got a regen built with the help of a young guy who was visiting area relatives.

I have a few questions to ask about components.

On a coil, the schematic may show X amount of turns on a X diameter form. If I use a different size form and wire size, (but using Professor Coyle) I can determine that the Q comes out to the same as what the schematic calls for will it still be ok to go that route?

How critical are the values of capacitors and resistors? I have been able to find info on resistors and capacitors on how to use them in parallel or series.

Will it make a difference where some of the parts ( coil, variable capacitor, battery connections, antenna and ground) are placed?

Also, I have searched online for sites that have instructions for this sort of info, but am unable to find anything that really helps. I have seen some videos (youtube) but they really haven't given me any help. Any links to check out?

Thanks for your time!

SW

Welcome to the site. Very Happy  I'll try my best, but I don't have that much experience with these set-ups. I'm sure some hardcore engineers will argue Mad 

Tuning involves L-C circuits. Inductor-capacitor circuits to resonate at frequencie(s). If you've modified a coil, but ensured it has the proper inductance and paid attention to the Q factor, I do not see why it wouldn't work. Capacitors are critical when it comes to the application. Simple blocking or coupling can use a standard plastic/polyester/whatever capacitor you have laying around. As long as you don't exceed the rated voltage of the capacitor in the circuit, then there shouldn't be an issue there. Now, when it comes to the "C" part of an L-C circuit for example, this needs to be a very stable, specific capacitor (assuming you aren't using a typical variable capacitor). Mica capacitors change very little with age and temperature. There tolerance is very tight and ideal for "tuned" circuitry.

Resistors are almost a non issue. Today's absolute cheapest resistors are far more accurate and stable compared to those of yesteryear. With any circuit though, if you deviate too much on resistance, you may adversely affect your circuit.

As far as layout. Good question. I think time and experience is really what it will take. As a general guide, don't have overly long wire connecting different points, especially in the tuning connections. Don't have coils cramped next to each other or by metallic or ferrous objects that could "detune" your circuit by slightly changing the characteristics. Keep power supply leads dressed away from tuning parts. Keep it simple and clean!

Here's something I found as well: http://makearadio.com/misc-stuff/regennotes.php


Sorry I couldn't give more specifics. Enjoy!
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Re: 1 Tube regen

Post by N7ZAL on Wed Jan 08, 2014 9:56 pm

Get a copy of the ARRL Handbook and it has tons of basic circuit information in it. You don't need a new copy and most libraries will have a copy.
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Re: 1 Tube regen

Post by Resistance is Futile on Fri Jan 10, 2014 5:13 pm

SWsenior wrote:I am new to regens but have made lots of crystal radios.  So to say the least, my knowledge is limited.  I just got a regen built with the help of a young guy who was visiting area relatives.

I have a few questions to ask about components.

On a coil, the schematic may show X amount of turns on a X diameter form. If I use a different size form and wire size, (but using Professor Coyle) I can determine that the Q comes out to the same as what the schematic calls for will it still be ok to go that route?

Yes

How critical are the values of capacitors and resistors? I have been able to find info on resistors and capacitors on how to use them in parallel or series.

I'm repeating some answers, but for clarification from my perspective.
Make sure voltages are same for caps if in parallel. Series caps add voltages.

Will it make a difference where some of the parts ( coil, variable capacitor, battery connections, antenna and ground) are placed?

Definitely, when you have components and wires in close proximity you will have what is called induction and sometimes called inter-electrode capacitance. It will change frequencies and then you will need compensation, or you will get squealing and howling.


Also, I have searched online for sites that have instructions for this sort of info, but am unable to find anything that really helps. I have seen some videos (youtube) but they really haven't given me any help. Any links to check out?

Thanks for your time!

SW

http://www.vcomp.co.uk/one_tube_1935/one_tube_1935.htm
http://makearadio.com/misc-stuff/regennotes.php
http://jbdkz.squidoo.com/my-radio-projects
http://www.bignick.net/Morgan_Radio/images/Morgan.pdf
http://hpfriedrichs.com/radioroom/pipsqueak/rr-pipsqueak.htm
http://www.antiqueradios.com/forums/viewtopic.php?t=61875
http://www.radiomuseum.org/forum/project_a_simple_one_valve_regenerative_receiver.html
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Re: 1 Tube regen

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