Diy hf linear amplifier. They are also expensive and easily blown.
Diy hf linear amplifier. Download Construction Data Construction notes Many examples of this amp have been built and I think the construction data is error free. In this video, we’ll walk you through the complete process of building a linear RF push-pull amplifier using two IRF630 MOSFETs. com: hf linear amplifierPower Amplifier DIY Kit, SSB Linear Power Amplifier 3. Chokes are supplied for the RF In, RF Out, Relay Cable, and AC/DC power line. You absolutely need band-switched filtering for the output to be legal. Input power 1-5mW. This 10W HF Linear Power Amplifier kit has no Surface Mount Components (SMD) to solder. Figure 1 – Amplifier Front and side View – Panels Removed The first version of this amplifier started service in the late 1970s and employed a pair of 813 tetrodes arranged in passive grid. Consider building an amplifier yourself, but if nothing else, enjoy reading the article. This produces a 250 Watt amplifier and has a strip line inductor to match the output. This N-Channel enhancement mode silicon gate power field effect transistor is an advanced power MOSFET designed, tested, and guaranteed to withstand a specified level of energy in the breakdown avalanche mode of operation. It will trip the amplifier protection circuit and set off an alarm if any of these are out of range. It was also dangerous (more dangerous than this one). Output power 45W (max) (this data is the first test of the data, the new data below). Jun 21, 2009 · 20 Watt Broadband Linear Amp - Inside Having the appropriate parts in hand and some designs on the internet to steal from, I set out to build my own linear. I have had a used pair of Eimac 4CX250B tubes for several years as well as a new pair of Eimacs, still in the boxes and figured it was about time to do something with them. Your fellow hams always helping out. The goal Unlocking HF Power with the ignoramus DIY Kit - MINIPA100 SSB Linear Amplifier! Latest Price & AMZN link here https://bit. Years back I had helped build a couple of valve (tube in the US) amplifiers using a single 4CX250B on 2 meters. Jun 19, 2020 · JBOT stands for Just a Bunch of Transistors. Here below you will find some shots of the various stages of assembly and a short video of the final testand now ladies and gentlemen start your engine!Gi7b homemade amplifier#Gi7b #HF # Jan 3, 2017 · This 5W HF PA kit features an IRF510 MOSFET as the amplifier. 8V 5W Input 70W Output Handheld Radio Receiver for Reception : Musical InstrumentsGood performance: With an overall gain of more than 40 dB, the radio transceiver is equipped with a fan for better heat dissipation during operation. Some … Jan 22, 2025 · DIY 45W SSB HF Linear Power Amplifier Amateur Radio Transceiver Shortwave Radio Development Board Kit $ 36. 8 to 72MHz, 6x onboard sensors. Jan 5, 2023 · In this article I have explained a few high frequency RF converter and preamplifier circuit designs which can be used for amplifying or enhancing the reception of an existing RF receiver. This project is ideal for ham radio enthusiasts and anyone QRP for HF is now popular – rigs such as the Yaesu FT818 or low power SDR transceivers are readily available. For a little bit of background, this type of DIY Kits 70W SSB Linear Hf Power Amplifier for FT-817 KX3 Ham Ratdio 13. Note: This list is DIY kit, you need to solder it yourself,not include the heatsink. Ham Radio Kits and Products PA500 linear amplifier with integrated automatic antenna tuner for your next adventure Ideal addition for QRP operation and digital emergency radio communication Dec 16, 2024 · DIY Kits 70W SSB Linear HF Power Amplifier for FT-817 KX3 Ham Radio 13. 8V supply using +15dBm input, over the range 3-30MHz 6) Operated with +20V supply Sep 12, 2017 · DIY Kits 70W SSB linear HF Power Amplifier FT-817 KX2 KX3 John, DK9JC & AK9JC Equipment 12. a. Full Kit is available @ ₹2900 + Shipping All components are soldered on the PCB 40m LPF pre-soldered You must find a good heat sink to fix the MOSFET and the PCB. 20W Linear Power Amplifier An amplifier primarily designed for use with Pic A Star but may well be useful anywhere only low level drive is available. The working amplifier will have the block diagram shown in Figure 1. The goal linear amplifier hf vhf home made with 4cx800 gu74b gu78b 3cx1200 3cx1200a7 8877 3cx1500 4cx250 4cx15000a gu36b Jan 1, 2018 · Here's a site about building, testing, experimenting with LDMOS HF amplifiers. Thanks for inquiring about our amplifiers - at this time we manufacture HF amplifiers that cover 160 m - 10 m and we also manufacture a standalone 6 m amplifier. Aug 25, 2022 · EVQ100 Linear Amp follows the same traditional approach of pull-push configuration to design this 100 Watt Linear Amp. I am targetting about 20 up to 45 watts with 13vdc. No schematic, no instructions. This Apr 6, 2005 · Well I finally decided to build an amp for a winter project. It can accommodate almost any driving radio, and only requires 2 to 3w drive for 1kw out May 22, 2018 · (Needed to make a working HF Linear Amplifier for Amateur Radio. Fre-quency of operation is extended beyond the limits of previous designs using the IRF510 and improved input-impedance matching. Ugly-bug construction was used but I dare say that the good results are partly to do with the method of construction. They are also expensive and easily blown. The 7& An amplifier board is just the core of a practical amplifier. September 2017 Introduction A broadband 100W linear RF power amplifier covering LF, MF and HF radio bands was created by modifying the 1W in, 100W out, 1. ly/41mcl5Zmore. io page: https://groups. I had a Yeasu 2100F, Heathkit Warrior, and Henry 2K3. I found that out repairing a 5KW FM recently. 12Vdc Fan Enclosure Panel mount SO-239 connectors Power supply connector Power Switch Fuse and Holder Low Pass Filter for desired Ham band (s) RCA female panel connector The amplifier uses a sophisticated circuit containing an advanced 16 bit microprocessor to control the normal functions of the amplifier along with the various high speed protection circuits, which will protect the amplifier from faults such as Overdrive and High SWR. 5‑30Mhz 13. Onboard sensors for supply voltage, instantaneous current draw, heatsink temperature, forward and reflected RF power Connectors for a separate Low Pass Filter bank Compact size, just 190x100mm Aug 20, 2013 · Greetings! This is my first post on this forum and I thought I would share my GS-31B linear and perhaps ask a few questions as well since there seems to be some builders on this forum with quite a bit of experience using the Russian triodes. Time to upgrade, so I built this one. There is a front mounted meter. May 23, 2022 · So I set about creating my first linear amplifier. But you can find lots of stuff on the web, fortunately. That amplifier worked well but the power supply eventually failed making a mess. This amplifier was developed to drive a 400 W linear amplifier using BLW96 transistors in class AB and to provide data for future development of a two stage amplifier for the same power with both driver and p. It is a necessary accessory for the 600W HF/VHF LDMOS linear amplifier in order to remove any harmonic products and make the amplifier legal to use on the air. First there is this excellent description by PD7MAA that you MUST read. Click here to browse through our top items or to make an order. Dec 16, 2019 · This design offers a practical solution for HF/low-VHF amplifier output filters, handles 600W and is designed to cover all amateur bands form 160m to 4m. 1. One of Motorola's new high-power transistors developed for single-sideband, the MRF-422, is used Jul 29, 2021 · The best place for up-to-date information about the PA500 amplifier is there groups. 8V, 50 ohm load. html Tube amplifiers are a popular project among hams. 8V Supply New 2025 Arrival High Reliable Electronic Component, Precision, Stable Performance Mar 20, 2021 · Driving the amplifier with another hf rig, say my K2, may free up the SDR wideband 0-80MHz receiver to be used to look for harmonic levels in the output and possibly intermodulation with a two-tone test. This project is presented by me for all you HAM's out there either who would like to build your first amplifier or for the veteran who's seen it all. The examples presented in Part 2 are single band HF and VHF amplifiers at the 5 W level — a par-ticularly enjoyable and educational class of amplifiers for the experimenter. Mar 15, 2019 · It's said to be a class AB linear amplifier for SSB AM CW FM power amplifier for low-power radio power connection and suitable for FT-817 KX3 other small power stations. Nov 8, 2019 · That’s where builds such as this well-engineered 600W broadband RF amplifier come into play. Another use of the "power Amplifier", is for use in receiving antenna distribution systems. In this article I will be concerned with wideband (untuned) amplifiers for use in the HF band (1MHz to 45MHz). This is my first home-brew amplifierI caught the bug after retrofitting a GI-7B into my GLA-1000 so I wanted to try building one from scratch. The most challenging so far has been developing an acceptable output power amplifier. Tube amplifiers are a popular project among hams. Ω Another home-brew HF amp project, a single EIMAC 8877 in a re-worked Harris chassis. io/g/diy599 here you can get all of your questions answered, and get the latest up-to-date and accurate information about PA500 amplifier. Ω Tuning a tube-type amplifier properly and why. VHF Linear Amplifier by SV1BSX There is not a personal design on this page, just I've transfered useful notes from PHILIPS RF Bipolar Transistors - Data HandBook (1993 Edition), about BLY89C VHF Power transistor, which is very popular among Amateur Radio "homebrewers". 50W LDMOSFET HF linear amplifier for the Red Pitaya by XQ2FOD https://ludens. com For simplicity, this article will discuss only the use and construction of a grounded-grid, triode type HF amplifiers. We simply take a lot of old ideas and put them into a sort of mental HL2-PA70 70W Power Amplifier for the Hermes-Lite 2. net The following describes a 160-10 meter linear amplifier that uses a pair of 3-500Z triode The B26-PA RF2K-S HF LDMOS LINEAR AMPLIFIER is now available from Island Amplifier USA finished, fully-tested and FCC-APPROVED. 3) Amplifier is still capable of 10W at 50MHz (6m band) though gain is down by 4dB compared to HF 4) Gain is 8dB down at 70MHz (4m band) compared to HF 5) With sufficient drive, the amplifier is capable of producing 20W output at 13. smiters from 100 mW to approximately 3W Has automatic, RF sensed, TR switching. Dec 2, 2019 · This is the first of a series of blog postings describing my latest homebrew project -- a 500 watt HF Power Amplifier: A low cost 600 watt ultra-linear amplifier for 40, 20, 17, 15, 12, and 10m This compact little amplifier is the brain-child of Pat Murdoch, ZL1AXB, in Auckland, New Zealand. Lots of power in a small space, a thermal management nightmare. Rick Campbell, KK7B In Part 1 of this series, I described an experi-mental method for designing a linear amplifier starting with a blank sheet of paper, some basic test equip-ment and an assortment of can-didate transistors. 300W EB27A HF AMP COMPONENT SET The EB27A HF amplifier is a push-pull linear amplifier for 300 watts of PEP or CW output power across the 2 to 30 MHZ band. 8V Power Supply Hot for New for Arrival 2025 High for Quality Brand: DOAMLIERWE Report an issue with this product or seller Hello everybody, this post is about my passion for DIY. Every design that I’ve seen looks nearly the same. DIY Kit 70w SSB Linear HF Power Amplifier Build - Since there are no assembly instructions or parts lists for this kit, I decided to create a build video. How Ω My work on a broken ETO Alpha 89. But it also includes a discrete component power modulator (like a voltage regulator), which is controlled by an 8-bit Digital to Analogue Converter (DAC). It is a simple, stable and easy to build 5 watts linear amplifier build out of a bunch of ordinary low power NPN transistors. There are a number of small transformers to be wound, and assembly requires care and patience. It's basically a "bag-o-parts" and a circuit board. x using the commercial DIY Kit 70W SSB linear HF Power Amplifier (aka 70W MiniPA), a Low Pass Filter, and an Arduino board, to control it all. The other two examples were buried in diagrams of elaborate transceivers that seemed to be “illustrative The 'HF' aspect is important because, unlike VHF devices, they are considerably more stable and do not have that disastrous tendency to go into VHF' parasitic oscillations. A low cost 600 watt ultra-linear amplifier for 40, 20, 17, 15, 12, and 10m This compact little amplifier is the brain-child of Pat Murdoch, ZL1AXB, in Auckland, New Zealand. Use of the chokes often BLF188XR Push-Pull LDMOS Amplifier General description: A 1400 W extremely rugged LDMOS power transistor for broadcast and industrial applications in the HF to 600 MHz band. LINEAR AMPLIFIER RFI KITS Palomar Engineers has RFI kits for many brand specific linear amplifiers as well as generic RFI kits for both AC powered and DC powered linear amplifiers. Just searched and found several again. Page 2 INTRODUCTION The Hammond HL1000A HF Linear Amplifier is a one-stage linear amplifier using one glass envelope 3-500Z Eimac Triode. stages working from a nominal 50 V supply. The final uses two IRF510 transistors in push-pull. About the Linear HF amplifier RE-PA30HF5C (prototype) This project uses a widely available IRF510 MOSFET. A 10 Amp circuit will do it, but I would go with a 15A circuit dedicated to just these two items. Many hams like the challenging of hunting for parts to build a high quality amplifier out of inexpensive surplus parts. 8 to 54MHz amplifier designed by Jim Veatch, WA2EUJ, Appendix 1, that utilizes NXP’s LDMOS MRF-101A transistor made for RF power applications. To get there, I need to build a lot of individual components that will come together in the final system. An HF 50-W Linear Amplifier If your QRP transmitter operates with 1 to 2 W output, and you have occasionally wished for moderate power increase, this project is for you! With a flick of the switch, you can increase your signal nearly 3 S-units going from 1 to 50 W. I just wasn’t getting the dynamic range out … Jun 16, 2018 · For this reason, although it is common sense, I must warn that before connecting the linear amplifier to a power supply for first time, make sure that the cursor (pointer) of the potentiometer VR1 is set to the ground side, that ensures the initial condition of zero bias before adjustment. cl/Electron/50Wamp/50Wamp. Linear HF VHF Amplifier kit with 2x MRF300 LDMOS RF power transistors. 59 eBay item number: 313219368147 Another choice is from Amazon: Collection of 15 HF Amplifier kits products. Moneysmith, W4NFR ; w4nfr@earthlink. A 600 Watt homebrew Solid State Amplifier and Power Supply Amplifiers are a favourite homebrew project. The amplifier uses four Motorola MRF150 50 volt TMOS power FETs configured in push-pull/parallel and biased for class AB linear operation. It covers 40 - 10 meters including WARC bands (12 and 17 meters). 8MHz to 54MHz 24dB typical gain, needs less than 3W drive High efficiency, typical draw 20A @ 44V. I have plans in the future for an HF amp so I decided that this 3) Amplifier is still capable of 10W at 50MHz (6m band) though gain is down by 4dB compared to HF 4) Gain is 8dB down at 70MHz (4m band) compared to HF 5) With sufficient drive, the amplifier is capable of producing 20W output at 13. x This is a work in progress to create a 70W power amplifier to be used together with the Hermes-Lite 2. The Amplifier is based around the MHT1803 Devices and is capable of up to 1000w on every band with the exception of 6M which is around 800w. +-RH Aug 25, 2022 · EVQ100 Linear Amp follows the same traditional approach of pull-push configuration to design this 100 Watt Linear Amp. My advice is to build straight forward building blocks and test each one to make sure that it is working. Aug 26, 2016 · The amplifier is controlled by a pic controller which monitors all aspects from voltage, current, power,swr to temperature. The anode panel meter carried 3kV! The amplifier and power unit Aug 22, 2021 · I had searched these almost a year ago, and found several options. Ω One of my home-brew HF amplifier projects, a pair of EIMAC 3CX800A7 tubes in a re-worked Alpha 76 chassis. 6 days ago · 600 Watt HF Amplifier Schematics plans by K9GDT and all infos to build a 600 Watt HF Amplifier. Easier transportation: the linear amplifier transceiver SSB comes with light weight In fact, it was harder for me to create the 5-10 watts of drive that this amplifier needs, than is was to build and test this amplifier. In December 2006 QST I described a single band SSB exciter with 0 dBm output. Listed under the Technical Reference/Amplifiers/HF Amplifiers category that is about Amateur linear amplifiers. We will send you a new one after receiving the defective item. . 8V Power Supply Diy Kit Electronic PCB Board Module SKU:012111 Jan 8, 2024 · Build Your IRF530 Mosfet Amplifier Since i am using low power SDR transmitters (5watts), i need a driver for my EL519 and SB200 amplifiers. These are suitable for low power data modes or CW but struggle on SSB – many operators are looking for a step up with a linear amplifier. 8V 5W Input 70W Output Handheld Radio Receiver for Reception Oct 9, 2017 · Linear, HF amplifier kit is designed to increase the power output of low power transmiters. May 30, 2025 · Output: 180W 13. 5 to 30 Mhz RF Amplifier This high range amplifier is very small [SB200 size] Vacuum variable input and output caps as well input and output switching. One of them, “An HF 50 Watt Linear Amplifier,” was a complex schematic that covered two pages. 80 FREE delivery Mar 13 - 26. Rick Campbell, KK7B This two part article describes a proce- dure to design and build a simple tran-sistor linear amplifier. diy kits a 70w ssb linear power amplifier for yaesu ft 817 kx3 running hf 80m 10m bands. 8V supply using +15dBm input, over the range 3-30MHz 6) Operated with +20V supply Linear Amplifiers may be quite frequency conscious, making them unsuitable for such techniques as "frequency Hopping" or even video. 1 An output level of 0 dBm (1 mW) is very com-mon for signal interconnec-tions between 50 Ω WA4GEG's scratch built 4-400A Kilo-Watt HF Linear Amplifier This 5-band 80~10 meter linear amplifier runs a pair of 4-400A tubes in grounded grid, and was originally built for a friend (now a SK) back in 1982. Dec 13, 2020 · Building and measuring my first few-watt RF amplifier Dec 13, 2020 I have a medium term project in mind involving a portable HF digital mode transceiver. VK-AMPS provides Ham Radio Kits & Modules. Why another linear amp? For many of us, getting hold of high power RF transistors is impossible. The WA2EUJ amplifier was the first place winner of the NXP design challenge in 2019, Appendix 2. It's not hard to make an RF amplifier, and yes there are basically a handful of common shapes, but there are a ton of difficult challenges in making a good one. AMPLIFIER RF DECK AMPLIFIER RF DECK HIGH VOLTAGE POWER SUPPLY HIGH VOLTAGE POWER SUPPLY WRITE UP & DESCRIPTION STONE CREEK SPECIAL (2) 3-500Z HF AMPLIFIER By William G. 0434867675 VK-AMPS PTY LTD ABN 91 674 181 821 We manufacture kits and amplifiers for amateur radio. All the RF amplifier circuits provided below are intended to be placed near an existing amateur radio receiver or a matching radio set in order to make the reception stronger and louder. 16K subscribers 19 Al wanted a low-cost linear amplifier to use with his 5 W QRP transmitter when band condi-tions got poor. Ω My work on an ICOM IC-4KL. The results have been compiled into these charts: The amplifier is slightly under 600W (about 580W) at 3. Over 600W from 1. Aug 2, 2013 · Greetings! This is my first post on this forum and I thought I would share my GS-31B linear and perhaps ask a few questions as well since there seems to be some builders on this forum with quite a bit of experience using the Russian triodes. High Quality 70W SSB linear HF Power Amplifier For FT-817 KX3 Ham Radio 13. Amazon. They never worked that well, but they were a lot of fun to build. It is usually optimized to have high efficiency, high output Power (P1dB) compression, good gain, good return loss on the input and output, and optimum heat This article does not present the “end all” to building amplifiers, but rather just gives a few ideas to build from or perhaps get the reader to contemplate other solutions for the problems that I faced. Homebrew RF Circuit Design Ideas "There is no such thing as a new idea. Shortwave power amplifier. Ω Learn about vacuum power Apr 16, 2021 · Building an HF amplifierBLF188/184 are now EOL pending replacement devices which have yet to be released. This model PA150 amplifier has outstanding performance in its class and represents truly exception value for money. Also RX / TX switching with external "PTT" input, forward and reflected power monitoring and display, automatic protection against high reflected power and high transistor temperature, thermal management (fans and air flow design), RF and DC connectors, chassis If you like projects and radio, you are in the right place! 300W LDMOS HF linear amplifier This is my HF amplifier that I use, which I put together in my garage. 600W, 1. The example shown uses an IRF510 MOSFET transistor to explain impe Aug 20, 2013 · PA150 HF LINEAR 200W Amplifier The PA150 is a 200 Watts SSB/CW rugged HF Linear amplifier units that will give many years of hard working service latest and smallest amplifier. Ebay lists DIY KIT MINIPA 100W SSB linear HF Power Amplifier For YAESU FT-817 KX3 AM CW FM $43. Ideally, the amplifier would generate at least 25 W on all the HF bands. Since this article is written for the "beginner", the triode tube is the easiest to work with. NXP Homebrew RF Design Challenge award winner. ) HeatSink Thermal Paste (Heatsink Compound) Bolts / machine screws (6) to mount PCB and TO-220's to Heatsink. com: Power Amplifier DIY Kit, SSB Linear Power Amplifier 3. And what am I? Make a working 100 Watt linear amplifier from a kit - Read this step by step guide for tips and instructions. Also keep in mind unless you are willing to solder the devices to a heatsink, the newer gemini devices are totally unsuitable for full limit linear service. Oct 9, 2018 · This 10W HF Linear Power Amplifier kit has no Surface Mount Components (SMD) to solder. 8-54 MHz It's been a while since I built an amp for HF; I'd have to go back to the 60's and a pair of the venerable 3-500z tubes that I put together back then. The modified Sep 24, 2023 · Amazon. 1KW HF/6M Amplifier Kit This is a complete 1KW HF amplifier Kit with fully assembled boards. I would recommend the amp and power supply be fed with their own proper circuit breaker to match the wiring of your home or the wire you choose to install for the project. Linear amplifier kits and filters available in the shop. These kits are designed to choke common mode currents going into or exiting from your rig. Jun 8, 2019 · The amp provides 26dB gain with +/- 1dB gain flatness from 2 to 30MHz. Note: I have many images of the build in progress- It will take some time for me to get this page into shape= I had been looking for a rugged HF linear amplifier with plenty of headroom. This multi part video focuses on the critical design aspects of an RF Push-Pull amplifier. After 30 years it made its way back into my hands where it remains as a treasured heirloom. I wanted more power on HF so Nov 4, 2021 · I've yet to do this, since my linear is an Ameritron AL-811A amp, that I bought from a silent key's family estate sale. We’re really impressed with the work that [Razvan] put into this power amp. A600 linear HF VHF LDMOS amplifier project using 2x MRF300. I did spend some money and took some time to get it all together, but the end result is WORTH IT! This project demonstrates how inexpen-sive power MOSFETs can be used to build an all-band linear HF power amplifier. Inspired by a design in “Experimental Methods in RF Design” EMRFD I set about building myself a linear amplifier to get above the noise. The unit is a completely self-contained table top unit capable of 1000 watts input. Yes, this humble low-cost MOSFET really is 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. Purpose. Here is a step-by-step Oct 26, 2025 · For ssb, AM linear power amplifier, CW, FM power amplifier, And the most basic signal amplification expansion. I The quest to build a 50 watt amplifier began my QRO project by searching my 1998 ARRL handbook for linear amplifier construction projects. Jun 19, 2011 · About RF Amplifier An RF power amplifier is a type of electronic amplifier which is utilised to convert a low-power radio-frequency signal into a larger signal of significant power, usually for driving the antenna of a transmitter. During a visit to an HAM exchange exhibition (Radiantistica Expo) I came up with the idea of building an amplifier using the mythical Russian tube Gi7b. Aug 22, 2020 · 22/08/2020 Building the DIY Kits 70W Linear Amplifier Introduction Like many other hams, I couldn't resist ordering a Chinese kit for a 70W amplifier for under 20$! This kit comes without any documentation, but luckily some good people have done all the work for us. A legal-limit version was also builta few photos of it are near the end of this article. Our collection of linear amplifiers is everything you need to boost your sound quality. Question is, when ever I wanna' attempt to do DIY linear amp building, do I want to go 'old school' tubes, or paralleled MOSFET's? Oh yeah For starters all the power for our amplifier is coming from a 120V outlet. DIY KITS 100W SSB linear HF Power Amplifier Review 2022 saleplace1 1. There isn’t a ton of creativity to be used when designing a linear of this class (Push-pull Class-AB). In the last decade, hams have pressed the power MoSFETs into use as RF devices. It is impossible. Yes, the power out will drop at higher frequencies. Gives up to 15dB gain and includes a resisitive atenuation network that can be configured to reduce power output of transmiters as needed to match the gain of the amplifier. Challenges For this design I am assuming the signal used to drive the amplifier is HF/6m Linear LDMOS Amplifier Kits has information about the latest version of this kit. I found three examples of linear amplifiers. See full list on qrpblog. A 1 KW SSPA for 1. The push-pull driver stage uses two BS170 transistors in the amplifier design used in the SoftRock transmitter stage. w87x o4xk osyfj pvozbo dg c6n4 6kufcfdq niodbxv 2e8 ad9