You could use a smaller transmitter to drive and RF amplifier. I would not use and 01A. A more practical output tube would be a 6L6 or 6V6. Look for my video on building a 6L6 transmitter.
To aviod floating, a grid resistor could be used to lower the grid Z.
In your example (where you move the signal to the scope lead to see a weaker voltage): You do have amplification:
But your way of confirming the amplification will not work, if your generator output Z was just near as high, as the chosen input Z of the input port of your RF amplifier. In this case, you need to disconnect the output of the amplfier when connecting the scope (high Z) to the signal generator.
The impedance of the input and output and the oscilloscope is high enough that there would be little change in the results. I'm just showing that it amplifies and not the amplification factor of the 01A.
That's always a good idea. Removing RF from filament is a very good idea, the RF path between the filament and the cathode is very short and could be troublesome. 73 Rick
This really shows the importance of RF chokes. What is the best way to determine how many windings, inductance, etc. the choke should have given a certain application? Is this why they have small chokes and capacitors connected to the filaments of RF tubes in TVs with series-wired filaments? Great demonstration!
Thanks. The number of windings depends on the frequency and the coil core, air or metal, or to combine this, the number of Henrys it takes to block a frequency. Yes the small chokes and capacitors are there to eliminate unwanted high frequency RF. Because the internal components of the TV RF tubes (all tubes) have internal capacitance and this internal capacitance would pass the unwanted RF along with the wanted signal, and this would cause a great amount of distortion.
Rick could you hook an audio signal to the audio input like a music source and a speaker to the output (where you have the ocilloscope connected to) and have it play music
Yes you can. I still have everything on the workbench, so I'll change out a few parts and make a few other modifications and it should then be an audio amplifier. Good idea! My 1920's radios use all 01A's for the RF, the Detector, and the Audio circuits. It will be interesting to hear music using a 1920's 01A tube and a new modern speaker.
that would be cool could you play the music thru the tube and record it from the speaker and then hook the output of the tube direct to your camera or computer and record the output directly? in another video that would be great thanks
That's right. The 01A was pretty much the first widely use commercial tube. That first tube (V1) in the DeForest Crosley 51 is biased by the grid leak resistor which is about 3megOhms, it's almost not needed. But the cost of the way the 01A is constructed is the 01A is a low power tube. The maximum plate voltage is 135 volts.
You have supremely exceeded expectations. Very, very good demo.
Don't know if you realize it, but you're the only one providing these electronic basics in a way that anyone can understand. You're the best, my friend.
Thanks. The 01A is an easy tube to use. For this demo I did not have to bias the grid at all. I believe in easy. I hope this demo will help to show one of the interest characteristics of RF.
Can this circuit be used to amplifie or boost the output signal of the Li'l 7 AM Transmitter???
dream501 6 months ago
@dream501
You could use a smaller transmitter to drive and RF amplifier. I would not use and 01A. A more practical output tube would be a 6L6 or 6V6. Look for my video on building a 6L6 transmitter.
AllAmericanFiveRadio 6 months ago
nice vid!
lightshadowds 1 year ago
Thanks lightshadowds
AllAmericanFiveRadio 1 year ago
Very nice! Thanks
To aviod floating, a grid resistor could be used to lower the grid Z.
In your example (where you move the signal to the scope lead to see a weaker voltage): You do have amplification:
But your way of confirming the amplification will not work, if your generator output Z was just near as high, as the chosen input Z of the input port of your RF amplifier. In this case, you need to disconnect the output of the amplfier when connecting the scope (high Z) to the signal generator.
larstinning 1 year ago
The impedance of the input and output and the oscilloscope is high enough that there would be little change in the results. I'm just showing that it amplifies and not the amplification factor of the 01A.
AllAmericanFiveRadio 1 year ago
Good video! Could we use a 226 tube for this also?
dream501 3 years ago
That triode will work also. Might need to adjust the control grid voltage a little and may even work better than a 01A. Thanks.
AllAmericanFiveRadio 3 years ago
Thank you. That was a very clear demonstration.
mrjimbopalmer 3 years ago
Thanks. I hope it helps.
AllAmericanFiveRadio 3 years ago
Thanks.
That's always a good idea. Removing RF from filament is a very good idea, the RF path between the filament and the cathode is very short and could be troublesome. 73 Rick
AllAmericanFiveRadio 3 years ago
This really shows the importance of RF chokes. What is the best way to determine how many windings, inductance, etc. the choke should have given a certain application? Is this why they have small chokes and capacitors connected to the filaments of RF tubes in TVs with series-wired filaments? Great demonstration!
CameramanLink 3 years ago
Thanks. The number of windings depends on the frequency and the coil core, air or metal, or to combine this, the number of Henrys it takes to block a frequency. Yes the small chokes and capacitors are there to eliminate unwanted high frequency RF. Because the internal components of the TV RF tubes (all tubes) have internal capacitance and this internal capacitance would pass the unwanted RF along with the wanted signal, and this would cause a great amount of distortion.
AllAmericanFiveRadio 3 years ago
Rick could you hook an audio signal to the audio input like a music source and a speaker to the output (where you have the ocilloscope connected to) and have it play music
coondogtheman1234 3 years ago
Yes you can. I still have everything on the workbench, so I'll change out a few parts and make a few other modifications and it should then be an audio amplifier. Good idea! My 1920's radios use all 01A's for the RF, the Detector, and the Audio circuits. It will be interesting to hear music using a 1920's 01A tube and a new modern speaker.
AllAmericanFiveRadio 3 years ago
that would be cool could you play the music thru the tube and record it from the speaker and then hook the output of the tube direct to your camera or computer and record the output directly? in another video that would be great thanks
coondogtheman1234 3 years ago
That's right. The 01A was pretty much the first widely use commercial tube. That first tube (V1) in the DeForest Crosley 51 is biased by the grid leak resistor which is about 3megOhms, it's almost not needed. But the cost of the way the 01A is constructed is the 01A is a low power tube. The maximum plate voltage is 135 volts.
AllAmericanFiveRadio 3 years ago
Professor Rick,
You have supremely exceeded expectations. Very, very good demo.
Don't know if you realize it, but you're the only one providing these electronic basics in a way that anyone can understand. You're the best, my friend.
Thank you very much.
Regards,
John
joernone 3 years ago
Thanks John.
I hope the video helps, you had a really good idea.
Regards,
Rick
AllAmericanFiveRadio 3 years ago
Thanks. The 01A is an easy tube to use. For this demo I did not have to bias the grid at all. I believe in easy. I hope this demo will help to show one of the interest characteristics of RF.
AllAmericanFiveRadio 3 years ago