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Some 50Volt Technology
- Thread starter Drifter
- Start date
"It's not MOSFETS. It's transistors". I guess he forgot what the "T" in MOSFETS stands for. Apparently BBI stands for Big, BIG idiot.
Unregulated power supply=
. So much for linearity and IMD performance.......WTF am I saying? This is an 11m amp. Linearity and IMD performance is merely a happy accident.
Unregulated power supply=
"It's not MOSFETS. It's transistors". I guess he forgot what the "T" in MOSFETS stands for. Apparently BBI stands for Big, BIG idiot.
Unregulated power supply=. So much for linearity and IMD performance.......WTF am I saying? This is an 11m amp. Linearity and IMD performance is merely a happy accident.
I'm curious. I'm not being a dick, I honestly want to know. I've seen you comment a few times the way you did above. Could you build a better amp that is practically priced and practical for a mobile application?
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I am confused, I thought it was a Base amp we were talking about here?
You gonna run a inverter in the Mobile?
73
Jeff
You gonna run a inverter in the Mobile?
73
Jeff
Watch the video. He spells mobile wrong but...
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I am not going to waste my time watching the whole Vid, but you can clearly see the AC mains Transformer inside the case, Base amp.
73
Jeff
73
Jeff
I'm not arguing that. Base amp. Yep absolutely. However in the video he advertises a mobile version.
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Tough question to answer. Could I build a better amp? Yes. Would it be practical for mobile use? Yes and it would not use a voltage booster to get 50 volts from 12 volts either. it would use straight 12 volts. 50 volts is for base use.Would it be practically priced? Depends on what you call practical. I have built a couple class ab 2x MRF-454 amps in the past for others many years ago, They were wideband covering 3.5-30 MHz for ham use and were based mainly on the Motorola engineering bulletin EB63. I have also built a few small tube amps for base use. My current project is reworking a one kilowatt television amplifier for use on 6m. It uses four MRF-151G MOSFETS.After that I may tackle another MRF-151G project for 2m. As far as ability....yes I certainly have it. I worked on commercial broadcast equipment for 22 years involving everything from tubes to MOSFETS and from the AM broadcast band up to 1.7 GHz.
My comments above stem from the fact that a dynamic power supply, one that is not regulated and allows the voltage to swing up and down with current draw, will cause the amplifier to have relatively poor IMD (Inter-Modulation Distortion) performance causing it to generate spurious emissions. It's an undeniable fact bound by the laws of physics. Also since most 11m amplifiers are class C my comments about any linearity being a happy accident ring quite truthful. Class C is not linear.
What BBI is doing in his video is nothing that has not been known or used for probably a decade or two. MOSFETS have been used since the 1980's in RF amplifiers. It just seems to be new to CB however unfortunately the MOSFETS being used about 98% of the time were never meant for RF but rather switching applications. They just happen to "work" at 27 MHz. If REAL RF type MOSFETS were used there would be a big leap in performance. Amateur radios and commercial gear have been using them for decades with GREAT success.
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50 volt devices have been in use for a couple decades. Nothing new really. The big advancements have been in the power available from a single device which is now exceeding a kilowatt.
As for the current draw, it is pretty much a simple ratio plus allowing a bit for inefficiency in power conversion. Four amps at 120 volts would translate to 40 amps at 12 volts plus a few more amps lost as heat in the conversion process. I hope he has made sure the maximum voltage in that unregulated supply will not exceed 50 volts. MOSFETS do not like to be over volted very mush at all.
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