@4:14 The goal of gate resistors has nothing to do with SWR. They work as parasitic suppressors. On high bandwidth devices operated at lower frequencies (most power LDMOS have quite high gain even above the GHz), these gate resistors along with gate capacitance create a LPF, decrease the input Q and lower the response/gain of the LDMOS above operational frequencies preventing destructive oscillations . Again, these LDMOS devices by themselves have a huge open loop gain even at GHz frequencies where negative feedback could easily become positive and the amp could potentially become a power oscillator if no preventive measures are taken when used at such low frequencies. Gate resistors are a cheap but effective safeguard on such low frequency applications. A similar technique can be seen in power tube amps, where parasitic suppressors are placed in series with the plates.
Hey sharky I was thinking when you moved I should have parked my camper at your new house and did all the interior work you needed done and traded work for work… BUT GETTING TIME AWAY FROM WORK TO WORK IS HARD .. hahaha make any sense ? I hope so cause I’m lost brother man.. lol hope you and the family had a great thanks giving and everyone is healthy doing great… Santa will be here before we know it … Kyle is in the right hands take care hope to hear ya out there in dx somtime brotha 73’s WOODCHUCK NY BACK QUIET . Ps sorry wasn’t yelling just big fingers little phone
"Hybrid combiner" When it gets to 100C Make a cup of tea! Where is the best place to get a good pcb design for the 1200W LDMOS? Thinking 2x single boards. 2.4k is more than plenty.
Probably a dumb question but could a liquid cooled copper block be used on something like this? Totally new to this stuff so I apologize if it's a stupid question.
What’s the point of bulky transformer for matching when LC matching components could be also be used. In my opinion it’s much easier to design a matching network using these components?
Hello Sharky. My memory seems to be slipping lately but I’m pretty sure I spoke DX with you the other day. Would love to ask you a few questions. Looking forward to part 2. Slingshot from Stockton.
Hello. I came across this channel in my search for information on how to set up a power amplifier for HF. This is some of the best and most informative content I've found on the subject. However, I was very surprised to hear discussions about using CB (27MHz) and 1000 watts. In Norway, where I live, we have a power limitation of about 12 watts SSB. What is the legal limit in the USA?
I just wondering what a box like that would cost, all I have ever ran is a 10 tube I think it's a phantom, and it said the same tubes in it for 20 years or more, I'm pushing 70 so I know nothing about the new boxes
Sharky it’s good to see you making videos again and sharing your knowledge
@4:14 The goal of gate resistors has nothing to do with SWR. They work as parasitic suppressors. On high bandwidth devices operated at lower frequencies (most power LDMOS have quite high gain even above the GHz), these gate resistors along with gate capacitance create a LPF, decrease the input Q and lower the response/gain of the LDMOS above operational frequencies preventing destructive oscillations . Again, these LDMOS devices by themselves have a huge open loop gain even at GHz frequencies where negative feedback could easily become positive and the amp could potentially become a power oscillator if no preventive measures are taken when used at such low frequencies. Gate resistors are a cheap but effective safeguard on such low frequency applications. A similar technique can be seen in power tube amps, where parasitic suppressors are placed in series with the plates.
This guy is head and shoulders above any of the other youtube cb amp "techs." He sounds like he's formally educated in electronics!
Maybe but not bbi or prime
I disagree. He might not have as much experience building amps, but he understands electronics and RF much better. @@SouthernFarmingTV
Awesome stuff here. Very interesting and educational.
Hey Sharky, don't keep us waiting too long for part 2.
Hey sharky I was thinking when you moved I should have parked my camper at your new house and did all the interior work you needed done and traded work for work… BUT GETTING TIME AWAY FROM WORK TO WORK IS HARD .. hahaha make any sense ? I hope so cause I’m lost brother man.. lol hope you and the family had a great thanks giving and everyone is healthy doing great… Santa will be here before we know it … Kyle is in the right hands take care hope to hear ya out there in dx somtime brotha 73’s WOODCHUCK NY BACK QUIET . Ps sorry wasn’t yelling just big fingers little phone
Beautiful bench!
Even if that thing somewhat worked, I can't imagine how filthy the signal is out of that box! Thanks for the videos.
are they dirty?
Your not lien the video looks sick good job bro.
Good to see you back nice to see Ur nice work again
Very Interesting.........Neat how lay it out in cad test it on computer how your going to make everything. To Smart. Thanks
First and super cool. Good to see you posting again.
Oh my god, I miss you so much. Please make more videos. 🙂
Hey Sharky, that box looks very familiar haha. Great video.!!!
Sharky where do I order your pallet kits from ? specially 27MHZ
"Hybrid combiner" When it gets to 100C Make a cup of tea! Where is the best place to get a good pcb design for the 1200W LDMOS? Thinking 2x single boards. 2.4k is more than plenty.
Probably a dumb question but could a liquid cooled copper block be used on something like this? Totally new to this stuff so I apologize if it's a stupid question.
What’s the point of bulky transformer for matching when LC matching components could be also be used. In my opinion it’s much easier to design a matching network using these components?
Hello Sharky. My memory seems to be slipping lately but I’m pretty sure I spoke DX with you the other day. Would love to ask you a few questions. Looking forward to part 2. Slingshot from Stockton.
Awesome Sharky!!!
I have had good results using a resistive splitter on the input. It flattens the imput Z and adds attenuation which is usually needed anywsy.
Sounds like a great choice for an ldmos project!
I hope the previous techs are not giving up their day job. 😢
Hey Sharky! good to see you.
Glad ur back
How You Doing Sharky,
Hope Things Are Well For You & Yours.
From KC8FPT In Cincinnasty Ohio
Hot glue and it blows up after repair? Its a Wizard Built after Butchered Built Idaho worked on it!
Hey Boss, would you share schematics for temperature controlled bias circuit? Cheers from The Netherlands
Enjoyed the presentation keep it up
Excellent as usual, I would like to talk to you about an amp for 144mhz I need big gain to bounce off the moon. I can subsidize the project please sir
1kw ie single LDMOS and stacked antennas. Made a few contacts with 1x 9 element but only to the big gun stations.
Hello. I came across this channel in my search for information on how to set up a power amplifier for HF. This is some of the best and most informative content I've found on the subject. However, I was very surprised to hear discussions about using CB (27MHz) and 1000 watts. In Norway, where I live, we have a power limitation of about 12 watts SSB. What is the legal limit in the USA?
I forgot to close the gate!
Fett, ran away, again..
Thx.SHARKEY.
I just wondering what a box like that would cost, all I have ever ran is a 10 tube I think it's a phantom, and it said the same tubes in it for 20 years or more, I'm pushing 70 so I know nothing about the new boxes
Ótimo trabalho parabéns gualidade total bazuka Foz do Iguaçu PR Brazil 🇧🇷🇧🇷
My first thought before anything is those heatsinks.. way to small. it's a start again project.
Its all Choked up ..
Genius!
3 biggest things i have seen killing these devices. Too much bias voltage. Overdriveing them and now enough cooling.
What's the fate of Mr.GoodNews amplifier? Did you make it run full power already... come on man, it's time for some updates... i'ts been over a year
Sharky!!!
BBI, Haven't seen a video from you in months! You still posting or is it our friends in TH-cam ?
To me the first obvious challenge is the heatsinks being upsidedown.
would not be easier to drill holes through the aluminum and use longer screws :)
Follow up?
Follow up?
🙏
Здравствуйте поделитесь пожалуйста схемой уселитель благодарю
Do more videos
Interesting how your approach is computer based and the builders approach was really just “primitive “
Bbi and sharky are my favorite
Sharky ur awesome mr610 waving from keystone