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"Pill" questions...
- Thread starter steved
- Start date
I have stated my opinion and you have stated yours.
We do not have to agree, this is a radio forum on the internet it happens.
Life goes on.
I will say that I am not confused about anything in regards to RMS power.
That term does not apply to RF Power measurements.
It often gets confused with Average Power measurements.
There is a well know manufacturer of CB watt meters that printed it on the face of there meters and it suddenly became a common error made by radio operators all over the web.
This subject has been beat to death over the years.
If you decide to not believe my real world experience with the Toshiba transistors or the results of Tom's testing that is up to you.
These transistors have been in service for years by many other users other than me and they will disagree with you.
But you are entitled to your opinion.
Again have a good evening.
73
Jeff
We do not have to agree, this is a radio forum on the internet it happens.
Life goes on.
I will say that I am not confused about anything in regards to RMS power.
That term does not apply to RF Power measurements.
It often gets confused with Average Power measurements.
There is a well know manufacturer of CB watt meters that printed it on the face of there meters and it suddenly became a common error made by radio operators all over the web.
This subject has been beat to death over the years.
If you decide to not believe my real world experience with the Toshiba transistors or the results of Tom's testing that is up to you.
These transistors have been in service for years by many other users other than me and they will disagree with you.
But you are entitled to your opinion.
Again have a good evening.
73
Jeff
I do offer a apology to the original poster of this thread for dragging it so far off topic.
Back to you.
73
Jeff
Back to you.
73
Jeff
Since the facts seem to be confusing to some, I'm going to lay it right out in black and white. Recently I was contracted to design an RF amplifier with some very unique requirements. This project resulted in 6 different amplifiers being built with 3 different transistors being tested in each circuit. Each transistor was tested in a single ended, resonant circuit and a push-pull pair. The advantages to single ended were so profound that I will never work with push-pull RF amplifiers unless broadband capabilities are required.
Each transistor in a single ended circuit made its rated power effortlessly. Matching the input and output were easily done perfectly using both strip line or resonant LC circuits. That goal is rarely achieved using RF transformers that have a fixed impedance ratio of 2:1, 4:1, 6:1, 8:1, ect. None of the push-pull pairs could outperform the same transistor in single ended. The main advantage to single ended, tuned amplifiers is they do not need a second device to complete the negative alternation of the waveform. They work just like a tube in single ended operation and depend on the tank coil to form the missing half of the waveform. Single ended amplifiers can also be biased into class AB to provide linear operation.
The bottom line is if you don't need to cover a broadband spectrum, push-pull is a waste of half of the output transistors in your amplifier. One in a tuned circuit will provide the same DC input and RF output capabilities as a push-pull pair. Before you disagree, break out any 2 pill and power supply with an ammeter. Try anything you want to exceed the rated collector current of one of those two transistors and the amp will blow up. If you can't support the input power of both devices, it's impossible to achieve the output power of both.
Each transistor in a single ended circuit made its rated power effortlessly. Matching the input and output were easily done perfectly using both strip line or resonant LC circuits. That goal is rarely achieved using RF transformers that have a fixed impedance ratio of 2:1, 4:1, 6:1, 8:1, ect. None of the push-pull pairs could outperform the same transistor in single ended. The main advantage to single ended, tuned amplifiers is they do not need a second device to complete the negative alternation of the waveform. They work just like a tube in single ended operation and depend on the tank coil to form the missing half of the waveform. Single ended amplifiers can also be biased into class AB to provide linear operation.
The bottom line is if you don't need to cover a broadband spectrum, push-pull is a waste of half of the output transistors in your amplifier. One in a tuned circuit will provide the same DC input and RF output capabilities as a push-pull pair. Before you disagree, break out any 2 pill and power supply with an ammeter. Try anything you want to exceed the rated collector current of one of those two transistors and the amp will blow up. If you can't support the input power of both devices, it's impossible to achieve the output power of both.
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