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RF Man Channel
Добавлен 1 мар 2017
This channel is design for CB and Ham Radio operators. It features videos demonstrating how to design and build HF RF amplifiers. It also offers Amplifiers for sale.
RF Splitters & Combiners - How do they work?
This video explains how a Hybrid RF Splitter / Combiner works. The main purpose of this device is to split or combine an RF signal while providing high isolation between ports and good impedance matching to 50 ohms. This design is commonly used with LDMOS and other high powered amplifiers. The splitter can take a single signal source and use it to drive 2 or more RF boards while the combiner can take the signal from 2 or more RF boards and combine their power output. This video also shows how to make insertion loss, isolation, and SWR measurements using a NanoVNA.
Просмотров: 13 767
Видео
(Part 6) How to Design, Build, and Test an RF Linear Amplifier (Output Board and Demonstration)
Просмотров 7 тыс.Год назад
This multi part video focuses on the critical design aspects of an RF Push-Pull amplifier. The example shown uses an IRF510 MOSFET transistor to explain impedance matching, biasing, amplifier classification, circuit stability, feedback, tuning, power output, harmonic distortion, and other important design characteristics. From this video, the viewer will gain an in-depth understanding of how to...
(Part 5) How to Design, Build, and Test an RF Linear Amplifier (Output Board)
Просмотров 9 тыс.Год назад
This multi part video focuses on the critical design aspects of an RF Push-Pull amplifier. The example shown uses an IRF510 MOSFET transistor to explain impedance matching, biasing, amplifier classification, circuit stability, feedback, tuning, power output, harmonic distortion, and other important design characteristics. From this video, the viewer will gain an in-depth understanding of how to...
(Part 4) How to Design, Build, and Test an RF Linear Amplifier (Input Board Con't)
Просмотров 10 тыс.Год назад
This multi part video focuses on the critical design aspects of an RF Push-Pull amplifier. The example shown uses an IRF510 MOSFET transistor to explain impedance matching, biasing, amplifier classification, circuit stability, feedback, tuning, power output, harmonic distortion, and other important design characteristics. It also introduces LTSpice as a simulation tool. From this video, the vie...
(Part 3) How to Design, Build, and Test an RF Linear Amplifier (Input Board)
Просмотров 9 тыс.Год назад
This multi part video focuses on the critical design aspects of an RF Push-Pull amplifier. The example shown uses an IRF510 MOSFET transistor to explain impedance matching, biasing, amplifier classification, circuit stability, feedback, tuning, power output, harmonic distortion, and other important design characteristics. It also introduces LTSpice as a simulation tool. From this video, the vie...
(Part 2) How to Design, Build, and Test an RF Linear Amplifier (LTSpice)
Просмотров 12 тыс.Год назад
This multi part video focuses on the critical design aspects of an RF Push-Pull amplifier. The example shown uses an IRF510 MOSFET transistor to explain impedance matching, biasing, amplifier classification, circuit stability, feedback, tuning, power output, harmonic distortion, and other important design characteristics. It also introduces LTSpice, a FREE simulation tool. From this video, the ...
(Part 1) How to Design, Build, and Test an RF Linear Amplifier (Overview)
Просмотров 31 тыс.Год назад
This multi part video focuses on the critical design aspects of an RF Push-Pull amplifier. The example shown uses an IRF510 MOSFET transistor to explain impedance matching, biasing, amplifier classification, circuit stability, feedback, tuning, power output, harmonic distortion, and other important design characteristics. It also introduces LTSpice as a simulation tool. From this video, the vie...
RF Chokes - what are they and how are they used?
Просмотров 7 тыс.Год назад
This video discusses the purpose of an RF Choke used to bias a Bipolar or LDMOS Power Transistor. It focuses on the design requirements, construction, and various testing techniques.
AM Demodulation Circuits and Audio Amplifier
Просмотров 4,6 тыс.Год назад
This video demonstrates how an AM Demodulation circuit works. It discussed the circuit topology and shows the resulting waveforms at each stage. The carrier wave used is 5 MHz with a 1 KHz tone used to modulate the carrier. The demodulated signal is then amplified using an LM386 Audio Amplifier. The diode in the video should be a 1N34A Germanium diode.
Superheterodyne Receiver Part 4 (Frequency Multipliers)
Просмотров 3,1 тыс.2 года назад
This video discuss the main circuits used in a Superheterodyne receiver. This is Part 4 of a 4 parts video which focuses on Frequency Multipliers and shows where and how they are used. Each circuit will be demonstrated looking at the wave forms and spectral components. Please check out my web site at - rflinear-amplifiers.com
Superheterodyne Receiver Part 3 (Frequency Dividers)
Просмотров 3 тыс.2 года назад
This video discuss the main circuits used in a Superheterodyne receiver. This is Part 3 of a 4 parts video which focuses on Frequency Dividers and shows where and how they are used. Each circuit will be demonstrated looking at the wave forms and spectral components. Please check out - rflinear-amplifiers.com
Superheterodyne Receiver Part 2 (RF Mixers)
Просмотров 3,6 тыс.2 года назад
This video discuss the main circuits used in a superheterodyne receiver. This is Part 2 of a 4 parts video which focuses on the RF Frequency Mixers and IF BPF Filters. Each circuit will be demonstrated looking at the wave forms and spectral components.
Superheterodyne Receiver Part 1 (RF Amplifiers)
Просмотров 4,9 тыс.2 года назад
This video discuss the main circuits used in a superheterodyne receiver. A 4 part video will focus on the RF Amplifier, Frequency Mixer, IF Filter, and Frequency Multiplier / Divider. Each circuit will be demonstrated looking at the wave form and spectral components.
LDMOS 1500w Amp For Sale
Просмотров 4 тыс.2 года назад
For Sale - A brand new 1500 watt RMS Dual LDMOS Amplifier with 54VDC /50 Amp Power Supply included. The Amplifier is designed for the High Frequency Band (1.8 to 30MHz) and supports all modes of operation including CW, AM, FM, SSB, FT8, etc. Units ships with schematic and operating manual. I also provide free technical support by email or Phone. Price $1899.00 Plus Shipping Product Description:...
New 65 Volt LDMOS RF Board (MRFX1K80H)
Просмотров 9 тыс.2 года назад
This video introduces my new 65 volt LDMOS RF Board. It used an NXP MRFX1K80H LDMOS Transistor and features a newly design broadband output transformer which saves cost. The board is designed to operate across the entire HF band from 160 to 10 meters. Please contact me if you are interested in purchasing one of these boards at 770-500-5945 or PM me on Facebook (RF Man).
Curve Tracers - What they are and how they are used to characterize semiconductors
Просмотров 3,3 тыс.2 года назад
Curve Tracers - What they are and how they are used to characterize semiconductors
Protection circuit for your LDMOS Transistors
Просмотров 1,9 тыс.2 года назад
Protection circuit for your LDMOS Transistors
How to build an RF Sampler for Ham Radio and RF Applications
Просмотров 20 тыс.3 года назад
How to build an RF Sampler for Ham Radio and RF Applications
Why do we need to stabilize a MOSFET Transistor?
Просмотров 5 тыс.3 года назад
Why do we need to stabilize a MOSFET Transistor?
Impedance Matching for an Output Transformer for a HF LDMOS RF Board
Просмотров 5 тыс.3 года назад
Impedance Matching for an Output Transformer for a HF LDMOS RF Board
Follow Up video on Impedance Matching using conventional RF Transformers and tuning circuit
Просмотров 1,8 тыс.3 года назад
Follow Up video on Impedance Matching using conventional RF Transformers and tuning circuit
RF Man - Impedance Matching in an RF Amplifier using Conventional RF Transformers and a NanoVNA
Просмотров 18 тыс.3 года назад
RF Man - Impedance Matching in an RF Amplifier using Conventional RF Transformers and a NanoVNA
RF Man Demo's New 6 Meter/1000 watt LDMOS Board and shows Harmonics with Low Pass Filter installed
Просмотров 7863 года назад
RF Man Demo's New 6 Meter/1000 watt LDMOS Board and shows Harmonics with Low Pass Filter installed
RF Man Demos 6 Meter 1000 Watt LDMOS Board with IMD Measurement
Просмотров 2,5 тыс.3 года назад
RF Man Demos 6 Meter 1000 Watt LDMOS Board with IMD Measurement
RF Man Demos New 2 Meter 1000 Watt LDMOS Board
Просмотров 9 тыс.3 года назад
RF Man Demos New 2 Meter 1000 Watt LDMOS Board
RF Man Demos Antenna tuner with LDMOS Amp
Просмотров 1,8 тыс.3 года назад
RF Man Demos Antenna tuner with LDMOS Amp
Great video but please get a tripod !!!
Too bad this channel has gone dark would have liked to have seen more content like this.
If someone wanted to build one of these amplifiers for the 160 m handbag, or lower, let's say one mhz. How would you calculate the input impedance. As it's not stated on the data sheet. A significantly lower frequency, I would assume it causes a gain increase in the f e t. But also the inductive capacitance would vary. So how would one actually calculate this?
I ask Dave question : what govens the height of the antenna off the ground at different Frequencies ? By the way Dave cannot tell me
Question: what wire antenna thickness that restricts maximum RF out put from transmitter be it 50 watts output?
this is very good video, explanation and direction are easy to follow. Would it be possible to screen record your simulation in the future? God bless
This is a very well explained and produced video, thank-you. I shall watch the rest of the series now.
Thanks for your comments! RF Man
@@carminecampo2045 Thank-You, I watched the series and learnt a lot. I will be returning and watching again as a refresher from time to time.
How did you choose the values for the tuning capacitors in the output transformer?
You can use 100V 50A TO220 pkg, dual diodes (in parallel) mounted on a heat sink. I have 10x1200 W SMPS in parallel. Works great. I have only ever loaded it to. 800 amps.
Fantastic video RF Man with plenty of usefull information. I have seen all series again and again in order to adapt your way of thinking and desighn. Thanks for your efforts and will to explain in such depth. Few questions, Are both Mosfet N type as in drawing or one is P type. Do the mosfet source :see: real ground? or the entire pallet is lifted? In order to be excited how does the gate founds a ground in order to close circuit? Thanks again 73
Congratulations. Your videos are master classes. They have allowed me to understand perfectly how an amplifier works. Are you going to post videos again? You are awaited with great interest.
Vey good !
Nicely explained. Very clear. Thank you.
Hello friend, where can I get these cores? I'm from Brazil, I search for which model on AliExpress, I would really like to learn and try to do this project, thank you very much!
Well I'm glad there's more to it because I was worried about getting all this in on video!
Nice video 🎉
If they're worried about core saturation using 43, just add more ferrite by using a larger core. I never use 61 in the HF range.
excuse me sir for my ignorance but does it work with an analog TV VHF modulator? Thank you in advance!
What would be the advantage of this splitter vs standard Wilkinson divider with transmission lines changed to coaxials. Resistor is needed as well this circuit has longer cables (wilkinson only lambda/4 length). Thank you interesting topic covered
What type of PCB material is this? FR4 or Rogers, PTFE etc ? I kinda assumed that ordinary FR4 was not so good at VHF
Just came across these videos, as a young buck 21 years old I can’t explain how much these videos will help me, I’m a diesel mechanic by trade but have been into cb for 2 years and have been wanting to build my own ldmos amplifier. But the learning curve just in terminology has been huge for me to overcome
It is really helpful for beginners, very clear explanation.
Realizé un "hybrid splitter" similar con núcleo binocular y cables corrientes.Necesité añadir condensadores en al salida de 25 ohms, pero funciona perfectamente.Supongo que es por falta de la capacidad del cable rg-316. También el combinador funciona de maravilla. Video útil y muy bien explicado. 73 's
Are the feedback resistors non-inductive? I would imagine that would be quite important for stability. Most film resistors seem to be spiralled and so slightly inductive. I wonder what you use?
Great and informative thank you! 73
Less noise in ring mixer
Wow I really like your video and is very interested
When designing these, I've always said there's a small bit of voodoo involved over stray inductance and capacitance over the layout. After doing the impedance calculations, the circuit should still be tuned, generally by a padder cap. You can get it close after the calculations, but layout and parts placement helps throw a wrench in the gears, so to speak.
TERRIBLE CAMERA WORK, motion sickness plus
Since both IRF510s present a 50ohm impedance would that mean the transformer would see a 100ohm impedance or since they are 180 Degrees out of phase they present themselves as one at a time at 50 ohms total?
Been playing with this design for sometime with pretty good results especially with a Pi LPF to reduce harmonics. However I was never able to get the 2 devices to work good with 1 xformer. Great video.
Thanks for another great video! 785
Another great video!. I always enjoy and learn alot from your videos. Quick question: The 2:1 auto transformer, the way I am looking at it might be wrong but I see it as a 4:3 turn transformer with an impedance ratio of 1.78. Is that correct? Thanks 785
I really like your technical explanation! Great video. 785
Ĺinear
Loving your videos. The overview of the individual sections is quite easy to understand. Are you able to tell me where to look for LTSpice models of the LDMOS fets? I'd really like to model the circuit for better understanding. I hope you can help.
You could build all this into a metal box with SO-239 sockets and an external RCA jack for keying, for a fifth of the price!😲
I must have missed it. On the transformer inductance. How did you arrive at 11.2uH? Seems to just appear without a calculation.
Great FB thanks 73 HANZ YL3JD
Sir, can I limit the output current of each boost converter to a certain amp, lets say I set each of their current limit to 10amps, and if the load draws 10amps, the first boost converter will do all the work, but when it draws 15amps, the second converter will kick in to contribute to the load sharing, and use shottky MBR60100 in each converters output to isolate them, this way with the shottky diodes the voltage drop is minimal compare to that of the resistor. This set up uses the second converter as a back up if the first one reach its current limit, this way Im not pushing the first conv. to its limits. Am I making sense?
So you basically have built a CDN for the DC range of under 10GHz😂great👌😎
Agreed. The LPF is indeed part of the amplifier. Anyway, the harmonic content of push-pull amps will be low in 2nd harmonic so the highest will probably be 3rd which will likely be around 20dB below fundamental. So the sum of the power in all the harmonics should be significantly less than 10%. Not really significant. Agreed in the two-tone test. Only way to test an ssb amplifier.
shortcutting sections of the inductor, it increases losses and lowers the quality factor
I've been struggling to understand the theory behind this for a long time, this has cleared up many things. Looking forward to watching the rest now, thank you!
Good job OM! Vy 73's
Thank you!
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I don't think that was a correctly am modulated signal to start with.
Hi, do you do custom work? I am looking for a fully built RF amp focused on 470-490 mhz. 3-5 watts. 12-15v dc. Do you have anything like this? Thank you, V
Hi RF Man. Thanks for these videos! I am seeking an RF amplifier that can input 250mw and boost to 3 watts+. Frequency range is 470-480mhz. Do you have any recommendations? Do you take on custom work? Thanks!