I'm sharing the info that was included with my recent order from HG
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HG2879C info
- Thread starter Tokin
- Start date
I hate to be skeptical but that datasheet appears to be a complete fabrication. So HG managed to get an additional 10 amps of collector current supported, along with another 110 watts of collector dissipation? I won't even begin to believe this until I can see 35 amps of collector current being supported through a single device. Someone please do this test so we can confirm the datasheet as bogus! If this is true, the Chinese have just developed the most powerful RF bipolar transistor ever made by a long shot. Not something we would expect from HG.
PS: Also notice the IMD is 6db worse and that's a factor of 200% worse. The gain is also well under half of the original part requiring twice as much drive.
PS: Also notice the IMD is 6db worse and that's a factor of 200% worse. The gain is also well under half of the original part requiring twice as much drive.
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I'm betting on you...
2879 "header" of the Datasheet...my archive
To be honest, it looks like they "cut and pasted" a data sheet and called it their own...
2879 "header" of the Datasheet...my archive
To be honest, it looks like they "cut and pasted" a data sheet and called it their own...
I'm literally shocked and totally have to assume it as false. In order to reach 35 amps at 360 watts of dissipation, the silicon wafer needs to be about a third larger and the gold wires at two of its three terminals have to be a third larger in diameter or more in number... I'd like to see the inside of the first one that blows up trying please?
When I first saw this datasheet, I said to myself "did they think to change the collector capacitance on this datasheet in proportion to the other increases in output capabilities, as we see in all other transistors? What I see is someone must have pointed that out, but possibly didn't have a clue how much to increase that number by. It only went up from 700 to 720 and well within the tolerance of a real 2879.
Guess what? Chances are that number is actually revealing more of the truth in proportion to the others. If not, these other specifications automatically require that the circuit output impedance used with the real 2879 would need to be reduced by nearly one third in order to match the new impedance that must result when 35 amps is drawn at 12.5 volts... I'll bet the darn thing can't handle 35 amps at DC with a pulsed 50% duty cycle, never mind at the top end of the HF spectrum or impedance matching.
If HG really has a new device that can meet their unbelievable published specifications, this is definitely a case where they should have followed NXP's lead and made a simple online video just showing the transistor sustaining 35 amps of collector current in a test that could be repeated by others.
When I first saw this datasheet, I said to myself "did they think to change the collector capacitance on this datasheet in proportion to the other increases in output capabilities, as we see in all other transistors? What I see is someone must have pointed that out, but possibly didn't have a clue how much to increase that number by. It only went up from 700 to 720 and well within the tolerance of a real 2879.
Guess what? Chances are that number is actually revealing more of the truth in proportion to the others. If not, these other specifications automatically require that the circuit output impedance used with the real 2879 would need to be reduced by nearly one third in order to match the new impedance that must result when 35 amps is drawn at 12.5 volts... I'll bet the darn thing can't handle 35 amps at DC with a pulsed 50% duty cycle, never mind at the top end of the HF spectrum or impedance matching.
If HG really has a new device that can meet their unbelievable published specifications, this is definitely a case where they should have followed NXP's lead and made a simple online video just showing the transistor sustaining 35 amps of collector current in a test that could be repeated by others.
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Well, that 360 watts and the IMD THD spec was not military -18 dB? Oh geez, no wonder it's 360 watts - it's pumping out 2nd, 3rd - 4th - ad infinitum...all totaled together?
See This Thread: link...RCI 69 base
Now this (at link) is their (Rangers') MOSFET RT1, RT2 and RT3 series, but if you had what Smokin' Joe found on their outputs - I can see where someone said - "that? Yeah - that's fine..."
Sure...Why Not - Not?
It's the literal - Cut 'n Paste format, that grinds me...
And it can't stand the light of day...
Too many things wrong with that picture...
See This Thread: link...RCI 69 base
Now this (at link) is their (Rangers') MOSFET RT1, RT2 and RT3 series, but if you had what Smokin' Joe found on their outputs - I can see where someone said - "that? Yeah - that's fine..."
Sure...Why Not - Not?
It's the literal - Cut 'n Paste format, that grinds me...
And it can't stand the light of day...
Too many things wrong with that picture...
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Wow! That RCI 69 has the worst 2nd harmonic content I've ever seen. This is the exact problem I've been talking about using power supply transistors in linear amplifiers. They are so filthy (even when not self oscillating) that they are unusable to those that know better. Imagine stuffing that signal into a larger amplifier? That's probably one of the reasons they don't make any base radios using such inferior amplifier stages. Every last one of them has been discontinued.
Now tons of people are running out to buy the mobile versions, put them on power supplies and drive bigger amps with them. I cannot begin to say enough bad things about this common practice. Even worse is some are investing a lot of extra money to install things like Hi-Fi modifications into them. If I were given one of these radios the very first thing I would do is remove or replace the entire RF amplifier board without question. It destroys what signal quality there is coming out of the radio in the first place. Use real RF transistors or skip the amp section altogether. No sense paying an extra $150 for something that may end your entire hobby do to its amazing ability to generate harmonic interference.
As I think about this more, I wonder how much of that harmonic content is coming out of the radios "wonderful" MOSFET final stage to begin with? Do they even put a 54 megahertz trap in this stage anymore? Is it tuned at 54 or "peaked" for watts? Is there any chance that spectrum analyzer is being over driven on its input, because that is a horrendous result?
That was one of my many rants earlier...the Finals' admittance (Tank circuit) and coupling to the input of the filter doesn't seem to be as "smooth" as they once worked and made - nearly by hand at times, with some of the older chassis I've seen come across - they took the time to make the window of the final stage work into the filter without too much loss or reflection causing losses as it passes thru.
At least you could make it swing forward for the customer without mashing the coils to do so...
At least you could make it swing forward for the customer without mashing the coils to do so...