HF Amplifiers: Design, Construction, and Maintenance
Find resources for building, modifying, and maintaining HF amplifiers, including tube and solid-state designs for various amateur radio bands.
HF amplifiers are key components for many ham radio stations, boosting transceiver output to achieve stronger signals for DX and contesting. This category focuses on the technical aspects of building, modifying, and repairing these essential pieces of equipment. Operators often homebrew amplifiers to match specific station needs, whether for a single band or full HF coverage, using a variety of active devices from classic vacuum tubes to modern solid-state designs.
Hams can find numerous projects for monoband amplifiers, like those for 40m or 20m, often featuring tubes such as the 3-500Z or GS-35B. There are also detailed guides for restoring vintage gear, such as the Dentron DTR-2000L, and upgrading popular commercial units like the Alpha 77D or Yaesu FL-7000. These resources provide schematics, construction notes, and practical advice for safely increasing power output across the HF bands.
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This high range amplifier is very small [SB200 size] Vacuum variable input and output caps as well input and output switching. -
AM/FM/CW QRP RF Power Amplifier for the HF 10 or 11 meterband (28MHz/27MHz) -
This article describes a 10 watt linear amplifier that is capable of delivering over 15 watts into 50 ohms and uses cheap plastic transistors that are used in CB equipment. by Harry Lythall - SM0VPO -
Based on Motorola MRF454, schematics and component list -
Use 4CX10000D / 8171, RF output power of 11 KW in key-down carrier on all bands. Power was measured with a Bird 4712 wattmeter and a 25 KW slug -
This is a project to develop an Open Source reference design for a 1500 watt solid state linear amplifier for 10 through 160 meters by K6IF -
Pictures of a homemade monoband linear amplifier for 160m band powered by 3 x QB5/1750 -
This article loaded with nice pictures and schematics, describes a 160-10 meter linear amplifier that uses a pair of 3-500Z triode power tubes. It was designed and constructed by William Moneysmith, W4NFR. The amplifier features fast warm up and 1500-Watt RF output with 100-Watts of drive. -
Home Brew a 4-1000A RF power amplifier project by W4NFR -
Pictures of a monoband linear amplifier for 40m band - 2 x QB5/1750 made by 9A6A -
This project uses a widely available IRF510 MOSFET, work on HF 80, 40, 30, 20 and 17 meter bands -
500W Power Amplifier by Harry Lythall - SM0VPO -
Schematics plans by K9GDT and all infos to build a 600 Watt HF Amplifier. The amplifier uses four Motorola MRF150 50 volt TMOS power FETs configured in push-pull/parallel and biased for class AB linear operation. -
An RF power amplifier, providing 7 Watts output in HF bands, schematic by ON6MU -
DIY kits a 70W SSB linear Power Amplifier for YAESU FT-817 KX3 running HF 80m-10m bands -
80m hexfet power amplifier by W7ZOI -
High-power 3-500 HF linear amplifier by Don Pinnock G3HVA -
The 20m monoband 4-1000 amplifier, by Jelmer (pa5r), Herman (pa0ten) and Frans (pa5ca) -
This compact little amplifier is the brain-child of Pat Murdoch, ZL1AXB, in Auckland, New Zealand. It is only 11" wide, 4" high, and 9" deep. Operates for 40, 20, 17, 15, 12, and 10m -
Ameritron QSK 5 PC mod for AL80B -
Alpha 77D,DX,SX, Alpha 76, Alpha 78 and 374 repair service and upgrade kits -
The Ameritron AL-1200 Amplifier is in current production. In its factory configuration it uses a single 3CX1200A7 (triode) tube, grounded grid configuration. Re-tubing the AL-1200 with a GS-35b with success. -
W7TDC modification of the Ameritron AL-80A power amplifier -
The two linear amplifiers are ment for use with QRP SSB/CW/FM/AM transmitters on the amateur bands 15 and 17 meters can be powered from a 12 volt DC supply by ON6MU -
A MRF141G 3-175MHz Broadband Power Amplifier DL4MEA 02/1998 -
Dentron GLA-1000 Conversion, modification with 4 x PL/EL-519 or 2 x GI-7B -
How retrofit the MLA-2500 with the Russian GI-7B tube to replace the 8875's which are both expensive and hard to come by tubes by W4EMF -
160-10 Meters 1500 Watt Amp - W4NFR -
Topic regarding a new 1KW HF power amplifier with 2x GI7B -
An RF power Amplifier for HF bands with 3 GI-7B tubes by CT1FMS -
Gi7b is tube designed for microwaves but working good as HF amplifier. Idea is to build cheap, reliable HF amplifier covering 160 meters band. -
HF QRP Linear Amplifier with 2x 2SC2166 + 2x 2SC1969 Push Pull Transistors (13.8V) -
I4FAF etrode Tube Linear Amplifier experience -
813 Linear Amplifier Project includes many schematics, drawind and assembling construction -
HF power amplifier project by YB0AH -
how to modify a Cb linear amplifier to use in HAm HF band -
Infomration schematics and pictures about various hf and vhf QRO linear amplifiers -
Italian page including pictures schematics diagrams of an home made linear amplifier using four EL509 in parallel. Output power is about 700W. -
A project for a 600-watt solid-state HF amplifier utilizing Motorola MRF150 FETs, with a focus on high-power output. -
Allow 9 bands and 1300 Watt output on the TL-922 amplifier with this document by PA0FRI -
L4B by Drake amplifier mod -
This page describes two modifications W8WWV made to his AL-1200 amplifier. The mods were obtained from Ameritron, so they are official. -
1500 Watt HF power amplifier -
N4ATS - Devoted to the Yaesu FL-7000 Amplifier. I have been rebuilding, repairing, and applying modifications to the Yaesu FL-7000 amplifier for 15 years. Over 200 units completed and counting! -
A solid state amplifier for HF and 6 meters band by N4IP -
HF Bands QRP linear amplifier by SM0VPO -
by Tony I0JX -
Robert Norgards KL7FM's, notes on upgrading the Heathkit SB-200 -
This is a Solid State Amplifier Project. It uses 4 MRF150 MosFet Power Transistors. The Power Supply Voltage is 50 VDC at 21.5 Amp. The max power available is 1,075 Watts. The Efficiency is about 65% +/- and runs Class AB Solid State. -
Scans of original G2DAF articles on his HF linear amplifier using QY3-125 tube -
Improvements to Using the Heath SB-200 Linear on Six Meters by Ron Klimas, WZ1V -
Revisiting the WA2EBY broadband HF amplifier -
The Yaesu VL-1000 Quadra HF Linear amplifier -
An HF 10-20m portable RF power amplifier based on the RD16HHF1 FETS giving 25 W. -
100 W output RF amplifier for 10 meter band project by W4NFR -
A HF power amplifier with a push-pull of AFT09MS015N. The (small-signal) gain of the amplifier is around 26 dB in the lower HF band and goes down to about 24 dB on the higher end and still around 21 dB at 50 MHz. Its input matching is relatively good at the lower HF and degrades above 10 MHz. -
HF power amplifier project powered by GU-78B by SV8JE -
The 60 Watt linear amplifier is simple all solid state circuit using power mosfet IRF840. -
A comeplete home made 600W LDMOS RF power amplifier. Settings can be made on a 7-inch touch screen, and on this screen you can see a lot of useful information during operation, such as output power, temperature, SWR, and so on. The power amplifier includes 2 MRF300 LDMOS FETs and several built-in sensors. The amplifier also contains several types of protection functions like too high current, too high swr, too high temperature, etc. -
A lower power desktop linear with integrated 120vac power supply. This, very compact, dual 811 version will deliver about 300 watts output. Covers all bands including WARC bands. -
A solid state linear based on EB104 Motorola Engineering Bulletin by Helge Granberg. It uses 4 MRF150 FETs in push-pull parallel to acheive 600 Watts from about 6 Watts drive -
A 600W 1.8 MHz to 54 MHz power linear amplifier made using rugged MRF300 transistors featuring output power between 580W and 750W depending on band, power supply: 48V, 18A typical, 20A max -
A simple RF power amplifier initially designed for 40 meter band can work on 10 15 20 40 80 meters -
This is a power amplifier project for a RF 600W 1.8 MHz to 70 MHz linear amplifier including a Low Pass Filter. Projects includes schematics, pictures, PCD design, fans details, note on PA ferrite chokes and assembling instructions -
Ameritron AL80B AL811H AL572 Amplifier Trouble Shooting. Tubes replacement, resistor changes. -
Alpha 87A Amplifier Fault 1 and the downlevel amplifier -
his article explores the construction of a PL519 tube amplifier, utilizing Ulrich L. Rohde N1UL's insights. Focusing on a modest 25W continuous output, the design ensures robustness with forced air cooling. The detailed breakdown covers input matching, screen grid voltage generation, bias adjustment, anode power supply, heater power supply, and monitoring circuitry, providing valuable guidance for ham radio enthusiasts. -
An amplifier made using an old HT-41 Hallicrafters Amplifier and adding the 160 meters band By W4NFR -
How to build a lightweight amplifier that can be backpacked around. -
A Solid State HF Amplifier with 16 mrf150 featuring 2.4 kW 1.8 MHz - 30 MHz -
An home made RF Amplifier project that allows near full power output from 813 tubes -
A picture gallery of a home-brew RF Power amplifier made with 3CX3000 -
The MiniPA Linear Amplifier for HF page discusses the popularity of QRP for HF among ham radio operators, such as those using the Yaesu FT818 or low power SDR transceivers. It explores the use of cheap kits from eBay or Chinese suppliers to build a 70-100W SSB amplifier using IRF530 MOSFET transistors. The article provides a review of the MiniPA design, including its features, components, and assembly process. It also highlights the importance of using a heatsink and forced air cooling for optimal performance. This page is useful for hams looking to enhance their HF rig with a budget-friendly amplifier. -
4CX1500B RF amplifier schematic, working 1.8 MHz to 29.7 MHz -
A document describing the reparing and restoration of an old Heathkit SB-101 power amplifier
