I have been building solid state amplifiers for many years. I'm a retired electronics engineer who designed the first Wi-Fi cards for both HP/Compaq and Dell some years ago. I even worked in the NXP lab for a short time with Doughty Amplifiers used in cell phone towers.
I have written a book "How to build a high power solid state RF amplifier - An LDMOS Amplifier Handbook"
It contains six LDMOS amplifier projects using the BLF188XR LDMOS transistor and several support projects that you may need to get your amplifier on the Air. I built the prototypes using simple techniques and then used Altium designer to model and lay out circuit boards to make it easy for the technically minded radio amateur to reproduce my results.
All the amplifiers are in the same form factor. They are 8x9 inches. They use a 8x9 copper heat spreader which sits atop an 8x9 heat sink with forced air convection cooling. These amplifiers are very stable and the 2.8KW amplifiers of project 4 and 5 will run at the legal limit even in digital and AM modes.
I will be marketing kits this fall and now offer PCB's and a few kits as rewards for supporting this project.
I designed a support power supply to convert 50 Volts DC to produce 12 volts for the relays and 6 volts for the BIAS current. I reworked a design I did for a commercial customer and increased the current output to 6 Amps (enough to power a QRP rig like an Heath HW-8, Ten-Tec Argonaut or Elecraft transceiver)
I have enjoyed building and designing amateur radio gear since I was a teenager and I know other will enjoy building these amplifiers as much as I did.
1 is a 160 or 80 meter linear single band amplifier that puts out 1250 watts in Class A/B service. It can be constructed for about $600 and is a great way to improve your country total on the low band on a budget
2 is an amplifiers that produces1250 Watts from 160 to 6 meters
3 is a design I first saw in the NXP lab It puts out 1400 Watts on the HF bands and was very well designed by NXP. The layout is mine and I have added those features required for amateur operation.
4 is a HF
legal limit amplifier - Rated 2.8 KW that is based on a Freescale design. This amplifier loafs along at the full legal limit of 1500 watts. We liquid cooling of the heat sink you can get over 2800 watts out in CW and SSB modes.
Project 5 is a 2.8KW amplifier that included 6 meters and is an original design that I now use as my station amplifier.
6 is a 2.5 KW 160-10m Low Pass Filter Module with relay band switching to use with the above amplifiers.
7 is a small very efficient power supply to supplu 6 volts for Bias and 12 VDC for fans and the relays
I have also included a chapter on front panel enhancements that uses a 2.8" TFT full color display driven by an Arduino based computer to monitor and control the above amplifiers.
These amplifiers easily fit in a surplus Zero case that I bought in Houston from a surplus dealer. The power supply I used is a surplus HP server power supply (model ESP120) . I have tested all the amplifiers in this book and will be offering kits sometime next year.
I'm using a large heat sink 8x9 inches and matching copper plate 3/8" thick.iquid cooling or a cold plate is even better. This I leave to you the Amateur radio experimenter.
Schematics, Full sized art work and parts lists for all projects are included in this book.
This is primarily a book project but as I have made PCB 's for all the above project I am including them as options as reward options. I will also make a few kits and will populate boards for the more expensive rewards.
I hope amateurs world wide will enjoy making and using these amplifiers as much as I did.
Risks and challenges
I have prototyped and characterized all these designs. The text of the book is compete and all the design work is done.
I used only parts available and in stock they are proven circuits however there is a risk some parts may be out of stock in the future. I will keep everyone informed that is part of this amplifier build.
Operation of this amplifier at the full legal limit of 1500 Watts should be very reliable. I will provide as much assistance as I can to builders. My hope is the book will have all the information necessary to build your own high power amplifier. The selection of case and thermal cooling are up to the builder,
These can be challenging to build for the beginner but an experienced kt builder should have no trouble reproducing these amplifiers.
The risks are really related to operating and cooling these high power amplifiers. Stay legal (<+1500 watts) and do not scrimp of the heat sink and cooling fans and you should be very satisfied with the performance.
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