How many watts from a 2879

[Shockwave]

OK, this could get the instantaneous current up to twice the current draw of a single device. The average should still be only be equal to a single device, since they're both off or close to it for half the cycle.

And had I bothered to read the rest of the thread, I would have already known that's already been accounted for.

Why would only the "instantaneous" current level go up? These single ended tests were conducted under CW carrier conditions. Whatever the instantaneous current is for one device during the half cycle would double with two over the same duty cycle. The "on time" has not been reduced by adding a second device but current and power dissipation have doubled. If the current path through one device can support 30 amps, two in phase and fed with enough drive for two, could support double the average current.

Further proof of this is the single ended test circuit for the Toshiba 2SC2879 produces nearly identical specifications as all the HF rigs that used a pair of them in push-pull. The main exception is the test circuit is narrow band and resonant while the HF rigs are broadband. One can do the work of two in push-pull and it's not on twice as long or drawing the current of two. The funny comment made about "free watts" is almost true once you understand the flywheel effect is in place here.

 

[Handy Andy]

Sounds like a Class A versus others...At least for the Single ended amp would need to be set up for 360 full conduction cycle meaning the split rail power supply and floating ground input and reference.

That's a true 30 amp - and is a Fire Extinguisher included?

Now, before we continue, you are making a separate reference for a flywheel or miller effect - which are typical "Fillers" for the missing information - doesn't mean it has the information you require- it just fills it in.

You mention a Dual-Tube drive design, similar has been done with Bi-polar but are still left with the level of performance pertaining to the Class the amplifier is pushed into. But to say that Combined in phase but only conducting 1/2 the time references Class B or maybe a Class AB and the collapsing coil and EMF kick - again only is a filler, and any information that was in the other 1/2 of the waveform, is lost.

Perhaps the reference to 30 amp is more towards the inefficiency of the amps ability to provide power except for the all (whole) conduction angle...That makes it a reference to Class A.

You also need to look at the cost of Bandwidth performance versus the tradeoff of limited bandwidth but better matching networks improving a separate level of performance and that's with coupling efficiency which again points back to the Biasing and Class of operation. At least to obtain output.

Am I following you here?

 

[TM86]

Why would only the "instantaneous" current level go up? These single ended tests were conducted under CW carrier conditions. Whatever the instantaneous current is for one device during the half cycle would double with two over the same duty cycle. The "on time" has not been reduced by adding a second device but current and power dissipation have doubled. If the current path through one device can support 30 amps, two in phase and fed with enough drive for two, could support double the average current.

Further proof of this is the single ended test circuit for the Toshiba 2SC2879 produces nearly identical specifications as all the HF rigs that used a pair of them in push-pull. The main exception is the test circuit is narrow band and resonant while the HF rigs are broadband. One can do the work of two in push-pull and it's not on twice as long or drawing the current of two. The funny comment made about "free watts" is almost true once you understand the flywheel effect is in place here.

I think I have it now. The 30 amps is the DC current draw of a single device. That was my error.

I was thinking of terms of devices being switched off half the time, since they're turned on for at most half a waveform, with 30 amps being the absolute limit in terms of current handling. Which would put anything beyond that as meaning the device could no longer be considered a non-smoker.

Feel free to correct me if I'm wrong, because it wouldn't be the first time. The instantaneous value of current flow through the transistor may be higher or lower than 30 amps at any given moment of time, as long it doesn't exceed 30 amps for the totality of a cycle of the signal being amplified.

 

[Shockwave]

Now, before we continue, you are making a separate reference for a flywheel or miller effect - which are typical "Fillers" for the missing information - doesn't mean it has the information you require- it just fills it in.

You mention a Dual-Tube drive design, similar has been done with Bi-polar but are still left with the level of performance pertaining to the Class the amplifier is pushed into. But to say that Combined in phase but only conducting 1/2 the time references Class B or maybe a Class AB and the collapsing coil and EMF kick - again only is a filler, and any information that was in the other 1/2 of the waveform, is lost.

If this were true, none of the rigs using a pair of 6146 tubes would be able to produce a clean SSB signal. They are in parallel, in phase and powered by a single rail supply so they cannot conduct into the negative region yet they are still biased to operate linear. Bias and class of operation is not dependent on being single ended or push-pull. That ability to reproduce a copy of the missing portion of the waveform in single ended circuits is the result of the resonant tank coil and the field collapsing back into that coil. Unlike an AF amplifier that would require a single ended device to be biased in the middle of the power supply voltage window to run linear, the RF amp is not reliant on this because its output circuit is resonate.

 

[Shockwave]

I think I have it now. The 30 amps is the DC current draw of a single device. That was my error.

I was thinking of terms of devices being switched off half the time, since they're turned on for at most half a waveform, with 30 amps being the absolute limit in terms of current handling. Which would put anything beyond that as meaning the device could no longer be considered a non-smoker.

Feel free to correct me if I'm wrong, because it wouldn't be the first time. The instantaneous value of current flow through the transistor may be higher or lower than 30 amps at any given moment of time, as long it doesn't exceed 30 amps for the totality of a cycle of the signal being amplified.

Hello TM86, I agree with what you've said above. The meter used to measure 30 amps on the single 2879 had no ability to measure peak amps so this is the average current the transistor was drawing while producing a carrier level of more than 250 watts.

 

[Handy Andy]

(You still have missing information - signal yes, whatever is bedded in it - is only available during that pulse cycle)

Ok, I see where were going with this, so I just wanted to throw this out there because of the issue with a type of capacitance that Semiconductor developers have used in LED's for some time with considerable success.

Deals with why a PN junction has, or exhibits - a capacitance across the junction.

So if you were to say, build an oscillator, the best method is to build an amp - that way you can see what it all entails to make the Amp oscillate - and tends to oscillate at a specific RANGE of frequencies due to varying factors but once all values externally are accounted for - the amp itself will start to oscillate at one given specific frequency then wander to another LOWER frequency...usually because of the internal capacitance of the semiconductor is also exhibiting a thermal flux to the doping regions and the sheer overall capacitance of the device in question - makes it SELF-RESONATE at that specific frequency or range of frequencies if you get my drift...(SIC)

In knowing these effects, I can see where; if we are possible to make such a device, you can make it work at a specific frequency, no higher or lower - to obtain the maximum levels of power delivery. Because you can maximize the capacitance internal to the device to your advantage you just have to make an inductive event or circuit to offset or work with it, either in series or parallel to cause the self-oscillation - then all you have to do is vary it's power by simply adjusting the input power to it as a variable waveform - heck, you an even induce a type of stability by also injecting a side-tone or undulation for sub-sonic correction to the devices tendency to generate another lower frequency as that device heats up and hence the junction's own capacitance is altered - so is the error correction to the signal - to bring it back to frequency.

So I'm with you there. (I think else - I'll segue off this thread..)

And now knowing this you are looking more into pulse modes of operation like Class E or F - or above. Similar to a charge pump where the device looks like a zero ohmic shunt a capacitor looking for a charge, or as Spock would say, Nature Abhors A Vacuum - until the electrical field exerts it's influence and the barrier or junction region - is full. But this takes time to do so. So, in a way, if we can adjust the area and thickness of the doping region - we can make such a charge pump possible.

 

[Shockwave]

This is really simple. Just look at the Toshiba data sheet at this link: http://pdf.datasheetcatalog.com/datasheet/toshiba/1468.pdf Examine the test circuit on page 3. Notice it's single ended, linear, biased and tuned for 28 MHz. Understand that all of the operating specifications have been derived using this circuit. Everything from the safe collector current rating to the IMD specification are all accurate using single ended technology.

That circuit has been public for three decades but we've never seen it combined because too many people thought they had to copy and combine the inefficient broadband, push-pull circuit for a narrow, mono band application. Two-Way commercial radio manufacturers have been combining narrow band single ended transistors for at least as long.

That circuit is also not the best that can be done by any means. It uses a diode for bias regulation where it should have regulation prior to the diode for improved IMD. It's also only operating at 12.5 volts for the 100 watt -24db IMD spec. Regulated bias and 18 volts VCC won't destroy that IMD spec at 200 watts although it will go down rapidly when driven beyond that point.

 

[Handy Andy]

Boy I'm glad you stopped by. Been looking for that circuit for years - since 2006 anyways. (public? hmmm...)

And you raise a good point, something I was trying to say earlier in the previous post. About a resonance issue.

This circuit is FREQUENCY SPECIFIC - so yes, the output will certainly go up, I touched on that even earlier in the original response I posted out here. Matching Networks - as in plural - not just output as some would think. You need efficient designs to make the ideas work.

So I don't see any true issues and 30 amps will be pretty hard on the circuit involved - hence the reasoning for the Fire Extinguisher reference.

And to think people wondered why 2.2 ohm resistor swapping off of from a ferrite bead for PC-122 Final and Driver was a crazy idea - I got it from circuit designs like that shown - in following a protocol I thought was a natural engineering design. So your thoughts of this then, stem from 30 A power delivery and proposed CONDUCTION ANGLE duration - as to how I see it. And a proposed power supply bias delivery system that many seem to have cast aside for the sake, or lack of concern for, purity. As in - the truncation of much of the signals' start and end in the crossover transition sense. (Lack of attention to details such as this tends to make them splatterboxes. You're pushing/distorting the envelope and the clipping that is occurring is simply wasted energy if you ignore it.)

And there will be an In-rush effect as the part develops the power output - then will stabilize shortly thereafter. The capacitance effects. Also, there was considerable lengthy discussions about Single versus Push-Pull back in the day of Usenet and the rec.radio fork of all those boards...they mentioned some relative effect to the power development using the theory of the self resonance and using inter-part capacitance. There may be a nugget or two to glean off those long and lengthy postings that you'll have to wade thru to find in them. But it may help you in discovering the smith chart and resonance versus the broadbanded networking arguements. Both have loss issues and prone to parasitic (SEE:MRF477). But if properly designed, a frequency specific board design - can easily do the ratings claimed.

One side benefit is the ability to tame the expected harmonics and matching network headaches using frequency specific designs to filter them out. A more efficient design can be implemented and installed to perform such a task with little loss insertion.

I wish you good luck in the endeavor - and in light of the work yet to be completed - hope it goes well. Thank you for answering my questions and helping me find some of the my past that got lost. It's a long story and no I won't bore you with details. But you helped me locate the design I had been looking for, but for some strange reasons always found something in my way in finding it.

The journey you're on may not be easy. But, I can hope it goes well.

 

[Handy Andy]

Some Eye Candy for the rest of us...


What's being referenced in the thread...

Be sure to cross your I's and dot your T's...

 

[Pete Fender]

Assuming you drive a vehicle with a stock electrical system it is not what you see in 99% of builders workshops! LOL

Have you taken the time to read Toshiba's data sheet aka White Papers? That is it's power output! Anything else is just ignorant rednecks doing stupid things with a cheap meter that is summing all power at all phase angles and freq. with in it's range!

So since you can clearly use a computer how about using google and finding the Toshiba white paper's in .000037 Seconds!

It is really a secret you see ignorant Hillbillies that are also 32nd Degree Free Masons have sacred knowledge handed down from Hiram Abiff that allow them to take advantage of zero point energy using a Toshiba 2SC2879 bjt. In fact Toshiba had to stop making these because the Masons where afraid people would start to open secret sacred portals to the after life and extract free energy which would allow Buba to transmit on 38LSB to Mars and back. Any water in the surrounding area would also spontaneously combust freeing the world from fossil fuel.]




Do you know Alex Jones??

 

[kopcicle]

Do you know Alex Jones??

hint, when responding to a quoted post get YOUR comment outside the [brackets] anon [/brackets] > insert inflammatory and possibly humorous comment here, outside the brackets.

Oh @Pete Fender , once you fire off a shot around here , no matter how oblique or pointed it is , you are now fair game.

Jus sayin :- )

 

[lonestarbandit]

Bobble jockeys, you do realise, all we sun worshipping 11m guys care about is:
When we "beller" something which sounds remarkably like "blurred wine, burled swine" into the microphone that our brothercouisin "Sugga shack Jed" can "heah" us right?
What in the name of Clint Eastwood does this fact filled mystical parlance you seem determined to argue into infinity have to do with "mah" belief that I "gits 275 Bwatts from mah one pill" ?

 

[Onelasttime]

If you can not laugh at my post you just have not lived enough, read enough or experienced enough!

Well and you have not watched enough builders on youtube of listened to them fight on social media or at get togethers.

I have heard crazier things on the air waves of Citizens Band Radio! LOL

 

[Onelasttime]

Easily the funniest thing I’ve read in weeks!! (And I read a lot).

Unexpected, well-designed, and on point. Thus enjoying the references (calculating likelihood) makes it just that much better. Funnier.

Let’s not forget Hollow Earth, Nazi Antarctic submarine bases, and The Black Nobility.

1953-manufacture Western Electric 300B tubes perfectly preserved on the DEW Line. Never touched since stored in 1957.

Vril, to activate the Antikythera Device.

Ha! No end to correlations.

Trust me I had to fight the urge to toss in more crazy stuff. I think I just hit too close to home for a lot of the guys on this forum.

 

[Handy Andy]

Trust me I had to fight the urge to toss in more crazy stuff. I think I just hit too close to home for a lot of the guys on this forum.

I can't get enough!

LOL!

It's the references to Demons, that reminds me of an earlier time...

The "Masters" is on, so I'll have to spend time with the wife...​