18 dB LT1253 DDS Amplifier by K8IQY
This 18 dB gain amplifier was built Manhattan-style to evaluate the Linear Technology LT1253 dual video amplifier as a candidate output amplifier for DDS systems employing the Analog Devices AD9850 and similar devices.
http://www.k8iqy.com/miscellaneous/18dblt1253ddsamplifier/lt1253ddsamp.htm

Basic Linear Amplifier by SMØVPO
This is both a project AND a bit of basic theory regarding the design of wide-band HF power amplifiers. As usual, it is prompted as a result of e-mail in which I have to repeat myself over and over again.
http://www.sm0vpo.com/tx/rf_pa_cct_00.htm

4-1000A Project HF Amp by NT8N
This is my new project an 80 -10 meter band switchable HF amp using a 4-1000A. I will be adding to this page as I proceed with the project. So check back often.
http://www.qsl.net/nt8n/project.htm

500 Watt PA by SMØVPO
Although I am an avid proponent of QRP (using reasonable power levels), there are times when I wish that I could run 1,000,000 watts and point it in a particular direction.
http://www.sm0vpo.com/tx/500w-txt.htm

70-100 W transistor HF versterker door PAØFRI
Hier zijn diverse HF en VHF projecten met transistoren letterlijk nagebouwd, maar in de praktijk was een behoorlijke modificatie nodig om een goed werkend apparaat te krijgen.
http://www.xs4all.nl/~pa0fri/Lineairs/BLW60PA/pa-blw60.htm

A MosFet PA by G3ONL
This circuit was described in Sprat 73 by G3ONL and is capable of 5 watts out on all bands. Diode D1 is included to protect the power device, preferrably a hot carrier or gold bonded germanium diode.
http://www.zerobeat.net/g3ycc/mospa.htm

HF Bands QRP Linear Amplifier by SMØVPO
This is a rather unusual QRP Power Amplifier design, with a wide frequency response; within three dB's from 300KHz to 30MHz. Overall gain is in the region of 16dB and the final output power may be well over four watts.
http://www.sm0vpo.com/tx/linear.htm

HF Linear Amp by EI9GQ
The 50R input of the amp. is matched to the 200R grid resistor by a 1:4 impedance ratio (1:2 Voltage) transformer. Screen grid (G2) voltage is generated by voltage doubling some of the grid drive RF.
http://homepage.eircom.net/~ei9gq/amp.html

HF Linear RF Power Amplifier by YBØAH
It is nowadays hard to find replacement for RF Final tubes such as 6146B 6JS6 etc. Stocks in the market seem to be very limited, besides it is very expensive too.
http://yb0ah.tripod.com/homebrew/project/pwr_amp/index.html

Masthead PreAmp by SMØVPO
I have received several requests for a masthead preamplifier for use in the VHF spectrum. The power and switching circuitry may be made independant of the frequency so here I have presented two versions of a circuit I used ...
http://www.sm0vpo.com/antennas/preamp-0.htm

Mini power Williamson Amplifier by JF1OZL
When I was about 14 years old, I learned about Williamson amplifier and Ultra Linear amplifier on the radio magazine. Such amplifiers was made by many tubes and Push Pull type transformers.
http://www.intio.or.jp/jf10zl/williamson.htm

My 813 Linear Amplifier Project by WB8ERJ
Actually this rig came back to haunt me. You see when I was in high school, I was a member of an Explorer post that was into Ham Radio. There was a big room full of WWII surplus gear. This particular rig was our "pet" project.
http://www.wb8erj.com/813amplifier.htm

PL519 FRINEAR 150, 150 W (QRP) Versterker door PAØFRI
Dit eenvoudige ontwerp van een HF versterker met een TV lijnuitgangsbuis EL519 of PL519 is zeer geschikt om het vermogen van een 5 W QRP transceiver naar 80 – 100 W te brengen.
http://www.xs4all.nl/~pa0fri/Lineairs/Frinear150/fri150.htm

PL519 400W HF Versterker FRINEAR 400 door PAØFRI
Er bleek vraag te zijn naar een "eenvoudige" en goedkope lineair voor een moderne 100 W all-band transceiver. ... Door regelmatig vlooienmarkten te bezoeken kan men onderdelen vergaren om voor een redelijke prijs ...
http://www.xs4all.nl/~pa0fri/Lineairs/Frinear400/Frinear400.htm

Push-pull Linear Amplifier with NE592 Driver by DL2YEO
Transformer T1 matches the relatively low impedance present at the VFO FET gate to the balanced inputs of the NE592. With a unipolar power supply, it is necessary to bias both inputs to roughly one-half of Vcc.
http://www.qrp4u.de/docs/en/rf_ampl/index.htm

QRO GU-84B Tetrode by NI4L
The GU-84B is a ceramic-metal forced-air cooled tetrode intended for use in power amplifiers with distributed amplification and for SSB-signal amplification with output power up to 2.5 kW at frequencies up to 75 MHz ...
http://www.angelfire.com/nb/ni4l/gu84b.html

QRP HF Linear Amplifier by SMØVPO
This project was a particular surprise for me in that the BC547 (equiv 2N2222) can be used to build a 500mW linear amplifer covering the entire HF band with excelent spectral purity and no neutralising at all.
http://www.sm0vpo.com/tx/qrp-hf1.htm

SMØVPO 500mW Linear Amplifier by VK2ZAY
This is my implementation of SM0VPO's tiny HF linear amplifier. You can find his original page about the design here: Harry's Homebrew Homepages.
http://www.vk2zay.net/article.php/04

TB3/750 FRINEAR 750 door PAØFRI
Deze versterker met een buis in een geaarde-rooster-schakeling is universeel opgezet om meer dan één type zendbuis te kunnen testen en gebruiken.
http://www.xs4all.nl/~pa0fri/Lineairs/Frinear750/frinear750.htm

The FARA HF Amplifier Project by WA1GPO
The FARA HF Amplifier project was designed and developed by FARA member Jim Valdes, WA1GPO. It was designed as an adjunct to the Yaesu FT-817 HF transceiver.
http://www.falara.org/tektalk/faraHFAmp.html