4cx250b 2 meter amplifier Jul 20, 2011 · 4cx250b amp I also have for sale the galaxy 2517 base radio that was used with this amplifier . 5w input , this tiny amplifier is providing about 50w output. I enjoy building amplifiers and have made several for 144 MHz over the years. They would also take the 3-500 as an option to give 1 KW output. The 4CX250B/7203 is designed to operate with a heater voltage of 6. 3 kilo ohms. 30-50 to 30-57; A 160- to 10-Meter Amplifier Using the 3CX1200A7 ARRL Handbook 1990, pp. The amplifier has been built in many variations. 30-46 to 30-49; A Legal-Limit Amplifier for 160 through 10 Meters (8877) ARRL Handbook 1990, pp. 600 The 4CX250B/7203 has a maximum plate dissi-pation rating of 250 watts and a maximum input power rating of 500 watts. E. I don't remember seeing an amplifier that covered 6 and 10 meters, but I haven't looked through my old books in a long time. I my amps i ran 3 tubes parrall on 6 meters and 2 tubes in push pull on 2 meters. instead of using pipes for the resonators I used lumped inductors, approx 3 1/2 turns of 3/8 copper tubing on each side with a pair of 100pf blocking caps on each side if I remember rite the tune cap is about 4" round and the load cap about 4 x 6 Jan 27, 2015 · 6m 200 Watt linear using a 4CX250B: 3W: 250W: 4CX250B: 2kV @ 250mA: QST September 1984: 10W: 300W: 4CX250B: 2kV @ 250mA: A 50 MHz, 250W Amplifier Using Push-Pull ARF448A/B (Class C) 8W: 250W: 2 x ARF 448: 125V: A 300W MOSFET Linear Amplifier for 50 MHz: 10W: 300W: 2 x ARF 448: 80V @ 6A: A Broadband, Solid State Amplifier for HF and 6 Meters There is no such thing as a "1 kW 4CX250B" amplifier. New posts Search forums. 3. HF-Amplifier with 4CX1000A build into the cabinet of All my high power amplifiers use valves and they tend to be noisy. This radio was bought new about 3 years ago and is like new . The First Amplifier made was the Explorer under the name Heatherlite. Lauched in 1986 the 2m Explorer using a single 4CX250B or a 4CX350B gave 300 watts on 2m with a drive of only 10 watts. T. At least it would be functional and Dec 15, 2022 · I settled on a 110 ohm swamping value from a 2 x 4x250b diagram from another 10-80 amp from 1960's ARRL Handbook. It is capable of a full kilowatt input on ssb, cw and R TTY, provided the power Apr 20, 2012 · So, I have some “inside info” regarding the 4CX250B and can explain why new tubes do not provide the life that older 4CX250B’s used to give. Its little wonder Acom found them an attractive proposition in their low cost entry-level amplifier offering. With a frequency range of 144-148MHz, it supports both FM and SSB modes. D. All hard wired . 39-43, 158 144 MHz High Power Amplifier using 2 x 4CX250B valves by Stefan Heck, LAØBY/DF9PY, April 1991, revised April 2000 General description The amplifier was designed for high power operation in CW or SSB mode and employs a pair of ceramic tetrodes type 4CX250B in push-pull configuration. As far as working condition goes it does work but I think this amp is a piece of junk! The amplifier is based on a design in the 3rd edition of the RSGB VHF-UHF Manual (Evans & Jessop), and uses pieces of copper water pipe as anode and grid. 414 * 80volts * 0. In most respects it is a typical grounded grid linear amplifier, with the exception ofRead More 1 4CX250B ceramic/metal tetrode 1 2N2905 receiver preamp transistor Meter reads RF power output. Sep 5, 2010 · Unless the amplifier has a CALIBRATED plate current meter, aligning the bias for a particular class of operation would involve having to measure dangerous points within the amp. This tube has been recently tested and meets all technical specifications. Major presumption here being that the 4x250b is same as 4cx250b/4cx300a. Info IARU VHF handbooks. Mar 28, 2025 · This shows an unsuccesful attempt to build a push pull 2 m amplifier, with the tubes in grounded screen. The circuit features a single 4cx250 circuit with band swtiched tuned inputs for the original 80-10 bands. I was lucky enough to own several of these jewels, I also got some new tubes as well and on a Bird 43 I could easily get 500+ on 2 meters and 400-450 on 432 with a good tube, the amps seemed to suffer a slight amount of thermal drift as the amp heated up on UHF with the Amprex DX393 tubes some came with, others came with the Eimac version (I Apr 6, 2005 · Sounds good on the antenna system. Proper cautions apply when working around RF and High Voltage please. Still with a bit of care you can make a nice low drive amplifier with 4x150a tubes. The current flows at the voltage peaks so the power taken from the RF signal is 1. 4cx250 the circuit will remain the same with maybe some variation in the output network tuning for optimum results. The output power is an impressive 100W, ensuring a strong and clear signal. The the 6 meter amp ran about 800 cw out ( 1200 pep ssb ) and the 2 meter one was good for 700 out Cw and about 1000 pep ssb. Power Estimates of 11 meter Amplifiers; Went to a local hamfest last sunday & saw a 300 watt 10/11 meter "brick" amp. 8 W. VHF linear amplifier pictures Jan 1, 2021 · Readings are approximate. As far as working condition goes it does work but I think this amp is a piece of junk! I have for sale a Dentron Clipperton V 2 meter amplifier rated @ 500 watts input with a 4CX250B. I noticed that as soon as plate/screen switch is turned on, tube starts to heat up. Six Meter three tube 4CX250 Amplifier. A freind of mine (now SK) Doug Beckwith N4CZT was a 4CX amp guru. this page provides information on the design and practical implementation of a rather inexpensive 144 mhz high power amplifier using a pair of ceramic tetrodes type 4cx250b by la0by. My book shelf. Standard RADIO-FREQUENCY POWER AMPLIFIER 2000 300 -250 250 250 12 2 1968 VOLTS VOLTS VOLTS WATTS WATTS WATTS by Varian Coaxial 2500 c 2500 c 2. I used to love to play with the 4CX 150's and 250 in my younger days. the 2-meter amplifier article. A European company is now marketing a 4cx250 amp here for HF. Often found at bargain prices, the 4cx250 tetrode is "a real bang for the buck". I purchased 2 meter 4CX250 :. The amplifiers get used for contests and special expeditions. Review Summary For : Gonset 903A 2 Meter SSB/CW Amplifier; Reviews: 1 MSRP: Description: 2 meter amplifier using a 4CX150 or 4CX250B tube for 350 to 375 watts output with 3-5 watts drive. 144 MHz High Power Amplifier using 2 x 4CX250B valves by Stefan Heck, LAØBY/DF9PY, April 1991, revised April 2000 General description The amplifier was designed for high power operation in CW or SSB mode and employs a pair of ceramic tetrodes type 4CX250B in push-pull configuration. But certainly not a linear amplifier. 025 amperes = 2. >> I think it would be fine if someone installed a much larger blower but >> that >> would require hacking the cabinet which would ruin the collectability >> of >> the >> amp. Click Here! (Will load in separate window - large file) The schematic may be familiar. Amplifiers are a favourite homebrew project. The loading they make to the G1 voltage corresponds to 2. Jan 1, 2021 · Readings are approximate. His input tuning circuit works perfectly. Jan 4, 2022 · This is an "ugly" but functional legal limit 6 meter amplifer. Plate current -. Plate A 144 MHz GI7B Power Amplifier; This construction article appeared in 1987 in Radiotechnika magazine (Hungary). 8 to 54 MHz combiner set Automatic Transverter Interface 1 KW 6 Meter LDMOS Amplifier 2 Meter 80W All Mode Amplifier 1 KW 2M LDMOS Amplifier 1 KW 222 MHz LDMOS Amplifier 500w 70cm Amplifier 1KW 70cm LDMOS Amplifier The #1 Vacuum Tube Manufacturers USA & Global. Should work great in the rover to get me to the 100 watt limit for Limited Rover entries. I have sold this to make room. The internal construction is very similar to the 2 meter amp, only things are shorter. 2 Meter Power Amplifier: No schematic. He built a 2 meter amp using 4 150b's. . Since it only had 25 amp fuses, I wondered how it could do 300 watts? HERE IS THE MATH: 13. This amplifier circuit features three 4cx250 tubes in parallel with tuned input. This amplifier is finally more or less finished. I have 1200vdc on plate ( old amp had 2400Vdc for a single 250B) 300vDC on screen and about -55v for bias. 50MHz 2 x 4CX250B Amplifier GW4RWR . It is only 11″ wide, 4″ high, and 9″ deep. To this day the 4CX250B remains cheap and plentiful and very easy to drive with low exciter power. Good luck finding a well built tetrode amp for 11 meters with shunt screen Nov 25, 2019 · For one example, years ago I built a single 4CX250B 2 meter linear amplifier in The Radio Amateur's VHF Manual (IIRC). I have for sale a Dentron Clipperton V 2 meter amplifier rated @ 500 watts input with a 4CX250B. 50 --- 0. Hello there, This file package is a scan of a Six Meter (50MHz) Amplifier from the ARRL Radio Amateurs VHF Manual. amplifier for that something extra on the 2 meter band. Use plenty of air to keep it cool. Listed under the Technical Reference/Amplifiers/VHF Amplifiers category that is about Amateur linear amplifiers. 8 volts X 25 amps = 345 watts, assuming 100% efficency. . Most everyone would go with the "upgraded" 4cx250b and similar. Also, with The 4CXB is an excellent tube for 1 - Schematic diagram of the 6-meter amplifier RF section. 0: 4CX250B (2) 70: Linear Tube-Based Amplifier: Not sure I'm reading 2 meter amplifier using a 4CX150 or 4CX250B tube for 350 to 375 watts output with 3-5 watts drive. Unless otherwise specified, 14 bare wire, 1/2-inch-dia, V1 socket – Elmac SK or SK 5 days ago · RF POWER LEVEL METER; QRP; Search for: Search for: HF-Amplifier with 4CX1000A; HF-Amplifier with 4CX1000A. com> >Sent: Tuesday HL-1K6 6m Amplifier - 6m - 50MHz~54MHz by Tokyo Hy-Power Labs 6 meter only amplifier. I have used it mainly for MS and EME operation for many years. There are some extra holes in the front panel where controls used to be located. 25 2,000 350 0. It covers the 160 through 10 meter amateur bands. Peak RF Grid Voltage. Nice looking and uses low cost tubes. They plug in and go after the grid bias is set for class AB1 linear operation for this tube. Dave helped me with my first 4CX250B amplifier and not long after I was making contacts with my 160-element collinear. Introduction This was originally a university project, designed from first principles in 1989. I am getting about 300-325W pep for a single 250b. 4CX250B x 2 (EIMAC) Band Switching These amplifiers were designed by ham radio operators using tubes that were designed for RF service. The Warranty period for this tube is Thirty Days from the date of purchase, for the original customer only. This amp has not been modified by me in anyway, and I have never had the screws out to look inside. 0 volts. Well, at first, it had many problems, because that book went to press before that amp was ever tested. Replacement Tubes Readily Available. The original construction was Inside the cavity is a short length of that 1. 4cx250B/7203 cpi | 4 c W50,000J General Electric Power Amplifier Models 4EF4A1, 2 and 3 operate in the 25-54 megahertz band. Parts List AntennaWorks 2 Meter 144 to 148 MHz 2500 Watt 8877 Amplifier: 2 meter 144 to 148 MHz 2500 watt 8877 amplifier AntennaWorks 2 Meter Amplifier power supply. Plate Input Power . Operate from 120V single phase primary. The amplifier features a GaAsFET switchable pre-amp, enhancing the overall Homebrew rack mounted 2-meter amplifier with power supplies and antenna switching relays - 350 to 400 watt output and utilizes a single 4CX250R tetrode. Gross, "A Parallel 4CX2508 Amplifier for 144 MHz," QST, May 1975, pp 11-14. For FM use Class C is efficient and works. 1 Variations are listed below, Plate-line mounting holes. Far better than the 811A The B-310G Mirage 100W 2m Linear Amplifier is a powerful device designed for radio enthusiasts. The amplifier was designed by Gabor Draskovits, HA1YA, who produces similar amplifiers commercially for export. I built a nice low drive single tube desk top 2-Meter amplifier, which gives me an easy 200 plus watts out in SSB mode. 8-54 MHz A 1. The amplifier now has a 4cx400/Russian GS36B tube and makes 600 watts at 400 ma anode current and no more than 2 ma grid 1 current on single side band. It is planned to fit 7 meters on the amplifier, 2 screen grid current, 2 bias grid current, HT Current, HT Volts and Power Out. EME soon caught my interest and after visiting K1WHS in Maine, I was hooked. 4CX250B x 2 (EIMAC) Band Switching I dont know why but my >> guess >> would be >> a solid state 300watt amp is $700 and you still need an Astron RS70 >> to run >> it. Driving Power. Oct 16, 2012 · I have an amplifier that had a 250 in it for 6 meters and ran a max of 325 watts flat out. Dec 18, 2002 · This document provides a summary of a 144 MHz high power amplifier design using a pair of 4CX250B ceramic tetrode valves in a push-pull configuration. RM ITALY LA 250 Series VHF linear amplifiers are wideband, compact amplifiers covering 140 to 150 MHz. It describes key design features and operating parameters, including an RF output power of 1000W with a gain of 21dB at 1dB compression with 8W RF drive power. Mar 25, 2015 · Tennesee walker amplifier I have owned many amplifiers over the years and as far as 11 meter band is concerned the Tennesee Walker is great ! It is constructed like most older cb amps like maco . A "1 kW 4CX250B splatter generator", maybe. ELECTRICAL CHARACTERISTICS Cathode - - Unipotential Oxide Coated Heater: HF amplifiers using these tubes, Codan, AWA, Collins KWS-1, etc. this vhf rf linear uses a 4cx250b forced air cooled tetrode and produces 250 w output for a drive level of approximately 3 w. Penta Labs, a proud American manufacturer and global distributor, has been the trusted name in electron tube technology for over 70 years. that was build for a tube linear amplifier for radio frequency and also have 2 x NOS sockets 2 x NOS 4CXB and only (at the moment) 1 x. Feb 28, 2004 · 4cx250 are old creamic tubes WORKHORSES on 6 and 2 meters. … Transmitting Tube 7203/4CX250B Removed from Military Equipment - Like new condition Used * No longer available for export MFR: Amperex SKU: 4CX250B-AMP-P. It was a DIY push pull design that used sheet brass suspended over PC board for the plate transformer, built from plans that were published in a ham radio magazine or ARRL handbook, don't This page provides information on the design and practical implementation of an inexpensive 144 MHz high power amplifier using a pair of ceramic tetrodes, type 4CX250B, in a push-pull configuration. The amplifier employs a 4CX250B as a power amplifier tube, with forced-air cooling providedby a blower mounted on the power supply. The superior construction of the 4CX250B/M makes it ideal for use as a grid driven RF amplifier or oscillator, or an AF power amplifier or modulator. This ampli- fier uses 4CX250B tubes (which are more com- monly used at vhf). That thing was hot! W6SAI Linear amplifier 2 meter with 3cx1500; DL4MEA The LKA-1 Linear Amplifier (two 4CX250B) (3,005,289 bytes, PDF file) QST June 1975, 2 Meter Power Amplifier: No schematic. 2. The article stated that the 110 ohm value was calculated for 30w max drive. 5 KW LPF for 160-6m 1. Dobricic, "A Three-Tube 4CX250B Linear Amplifier," ham radio, Apr 1987, pp 63-72. I didn't like the idea of one switched meter, as both valves need to be observed for linear operation. W-output) VHF transceivers. The five holes in the right end (facing front) of the upper chassis (used to mount the 2-meter plate line} are not requ. Home other things 1 KW 6 Meter LDMOS Amplifier 2 Meter 80W All Mode Amplifier 1 KW 2M LDMOS Amplifier 1 KW 222 MHz LDMOS Amplifier 500w 70cm Amplifier 1KW 70cm LDMOS Amplifier A Big Power Supply for SSPAs Low Pass Filter/Dual Directional Detector Sampling RF Power LED Bar Graph Meter Amplifier Control Board LNAs (preamps) and MMICs LNA Sequencing and Protection High power amplifier for 1296 1 KW SSPA for 1. The original construction was Description of a 144 MHz high power amplifier for 2 x 4CX250B by LAØBY This page provides information on the design and practical implementation of a rather inexpensive 144 MHz high power amplifier using a pair of ceramic tetrodes, type 4CX250B, in a push-pull configuration. The plate bypass is constructed the same as the 2 meter amp except the brass plate inside is round. A single 4CX250B - Producing 250W linearly, 400W in class C. Designed for AM operation! (Not a stressed out SSB power supply) ===== Discussion: Although the initial project will be based on a single 4CX250B, I would like to have a power supply capable of operating two in the future. Feb 17, 2008 · 4cx250b amp moved to ebay ! Two Tube 4CX250B Expert Electronics 10 meter Base Amp! - eBay (item 330600753254 end time Aug-13-11 14:26:09 PDT) Reply. They never worked that well, but they were a lot of fun to build. Page 5: Chapter 3 Chapter 3. Not recommended. 813 in 1. All different. I added the 144MHz two tube amplifier which follows the six meter project detailed in the book. May 6, 2013 · this 50 mhz rf amplifier uses a 4cx250b forced air cooled tetrode and produces 250 w for a drive level of approximately 3 w . CLASSIC 6 METER AMPLIFIER SINGLE 4CX250B TUBE W4NFR 2-8-1982. It is simple and 1500-W-Output Amplifier for 160 Meters (3CX1500A7) ARRL Handbook 1990, pp. I have used ZL1AXB 's 813 amplifier plans and have modified it to my own needs. uk>; <amps@contesting. Mar 8, 2007 · Biggest bunch of thrown together junk ive ever seen,friend of mine paid 1800. The G1 current flows in short pulses. 325 W/4 ohms with QSC IT-42 . They are 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. The amplifier that you want could be built using a 4CX250B and the tube would last forever at 200W PEP. I have 2mtr amp with tube FT817 portable antenne FT817 "buddipole" clone Regenerative audion 1929 CW transmitter Loop antenna 144Mhz 300Watt amplifier 2SA13, 144Mhz beam Filter design ATF54143 LNA 1Ghz VSWR bridge PEP power meter Glowbugs. 2-. The antenna will do more justice than the amplifier anyway. Available in two models, the only difference is that the LA 250 V includes a pair of cooling fans while the LA 250 does not. com> To: <amps@contesting. This is a 2 Meter (144-146MHz) high powered linear amplifier. It was described in the October 1956 QST. Picture 1 Amp (And I did it myself!) Picture 2 Power Supply The amplifier schematic. EL519/6P45S (6П45C)Tube Amplifier Tube 6P45S is a EL519 equivalent 300w amplifier 4w input on 20m This following one using a single 6P45S and provide about 130 up to 150w 150W amplifier with one tube with N7DDC ATU display on the front panel With about 1. It has 2400 volts on the anode and 350 on the screen. But (bingo!) you were correct when you said something in the way tubes are being manufactured might be involved. 4cxb Amplifier Schematic This voltage and current is maintained with a KW 2m PA mit 2 x 4CXB: DJ4PI Amplifiers EIMAC DF9IC LDMOS Power. is 300v current resting is low peaking up to 10-20 ma. 640 in Forced Air OPERATION DC Plate Voltage . Meacham, "A High-Power 2-Meter Amplifier Using the New 3CX800A7," QST, Apr 1984, pp 11-15. The 3/16 nch (S mm) holes that fasten the 1-1/4 meter plate line to the chassis are located by setting the line SV3AEO HF Linear amplifier SV1DOQ AMPLIFIER 2 X QB4 SIMILAR 4-400, AMPLIFIER 8 X QB4 OR 4-400 tubes 5kw,HF LINEAR AMPLIFIER 6 X QB4 OR 4-400 TUBES, 4KW HF LINEAR AMPLIFIER ( 2 X GU84B ),VHF LINEAR AMPLIFIER 1Kw 2 X 4CX250 PUSH SB-200 Heathkit Modificaties,PA0FRI S55AW 2m PA GS-35b SM2CEW The G2DAF HF amplifier SM2CEW EME amplifier for 144 MHz Carl wrote: >----- Original Message ----->From: "Ken" <kenw2dtc@comcast. com> Sent: Wednesday, April 13, 2005 6:21 AM Subject: [Amps] FS: DENTRON CLIPPERTON V 2 meter amp 500Watts >I have for sale a Dentron Clipperton V 2 meter amplifier rated @ 500 watts > input with a 4CX250B. Pettis, "HY-brid HI-power," QEX, Jan 1990, pp 13-14. Stability becomes increasingly difficult when the frequency is raised into the 10-meter range. The following year I hacked it for two valves in parallel. Years back I had helped build a couple of valve (tube in the US) amplifiers using a single 4CX250B on 2 meters. The amplifier to be described, which covers 80 through 10 meters, should fill the bill nicely for those who wish to run higher power and use the low-power transmitter for an exciter. Sep 30, 2020 · I had the good fortune to pick up a 222 MHz amplifier to go with my Q5/DEMI 222 Transverter. MHz W Power Amp by KL7UW This page describes the construction of a watt 2m amplifier using an The design follows the. Linear Amp: 30. 000v) must remember that VHF linear I have built several single and 2 tube 8877 amps for 6m using a knock off of the w6po 2 meter amp. Al - K8EUR ----- Original Message ----- From: <JimMoci@aol. This radio when drivin into this 4cx250b amp it will swing to 2,200 watts ! Dec 30, 2009 · But if London Power do that 4CX250B tube bass amp with 700W, I think I can build one with 200 / 240 W about voltage (1. Initial S. Jan 13, 2025 · I got a pair of NOS 4CX250's with the Eimac chimneyed sockets and the 2 meter RF amp that was wrapped around it all probably 20 to 30 years ago at a hamfest. Amplifiers. Within maybe 15 % on the lower bands. This produces a 250 Watt amplifier and has a strip line inductor to match the output. The 4CX25()R will replace the 7580 in almost all applications since it is electrically identical except for a minute (0. Schematics and construction details are referenced in additional files. 5" copper pipe like the 2 meter amp. After college and while in the Navy, I began experimenting with 6 and 2-meter meteor scatter. 1500-W-Output Amplifier for 160 Meters (3CX1500A7) ARRL Handbook 1990, pp. DC Screen Voltage DC Grid Voltage DC Plate Current DC Screen Current. For AM and SSB power amplifier model power amplifier reflect o meter x e 481 cri 100 1 000 e 481 4cx250b-or 7032/4cx250b grid 2 9 neutralizer grid cavity c484 The Penta 4CX250B/M is a forced-air cooled, 250-watt plate dissipation, external anode, ceramic and metal radial beam tetrode. 39-43, 158 The 4CX250B is a very low drive tube with only 2 watts of grid dissipation. A 2 meter class C amplifier with 4CX250B has a tube efficiency well above 80% while a QBL5/3500 will give between 60% and 75% also in class C (higher plate voltage Aug 8, 2005 · 2 4cx250b? 4 4cx250b? 1 4cx1000A dxHome. Most amps using them in pairs can be driven to full output with just five watts drive. The first units covered 10 to 80m and gave around 800 watts from 2 x 4-400. They typically require only a few watts for full output. N4IP HF and 6 Meters amplifier A solid state amplifier for HF and 6 meters band by N4IP 144 MHz PA with MRF317 A 2 meter power amplifier 144 MHz 1. net> >To: "Ian White GM3SEK" <gm3sek@ifwtech. The unit uses a 4CX250B in grounded grid, which makes it usable with most 2 meter rigs that have outputs in the 16 to 20 watt range. Multi-band HF amps, have a few difficulties that grow more complex as more bands are added to it. Incidentally I get around 3 to 5 years life on old 4CX250B’;s in a GE 250W FM repeater. Further, it will replace the 4X250B or 4CX250B in equip- The whole supply will be continuously monitored by the control logic and shut down as required, if a fault occurs. These high-power 2-meter amplifiers will provide up to 200 watts FM output. Conduit for power supply connection High voltage connector OPTIONS: 2X 4CX250 Tetrodes W/2-meter tuned lines, integral Anode clamp, DIY Linear AMP!! QSC CX302 2-Channel Power Amplifier 120V. aB1 aF amplifier or modulator 2,000 0. If you're lucky enough to have an accurate front panel plate current meter, the bias would be set at 400 ma with the relay keyed and no drive applied. 1 - Schematic diagram of the 6-meter amplifier RF section. Teflon can be seen at the air exhaust opening at the top. dxForums. The top cover has been removed where the plate line and grid compartment can be seen on the amplifier built in May 1967. 8 to 54 MHz Dual Directional Detector 1. This amplifier was constructed as a portable amplifier for use on 6 meters. They are used with an external driver and power supply to provide a power output between 150 and 300 watts. It has an input power of 1-8W, making it ideal for handheld radios. However my amp was for 2 meters so I can't help with HF amp ideas for these tubes. 2 uuf) increase in output-capacitance limits. a dayton blower was HL-1K6 6m Amplifier - 6m - 50MHz~54MHz by Tokyo Hy-Power Labs 6 meter only amplifier. 55 W is used to heat the grid. Handy size. Amplifier tube screen current is monitored by an LED indicator. 00 for a 2 /4cx250b amplifier brand new and was nothing but junk. *** Note: Amplifier Color may vary. The primary design objectives were that it be inexpensive yet work well. Plate voltage is about 2kv with 47 mfd of filter. I built a single tube amp for 2 meters way back then. It is the mosfet transistor type and will swing close to 50 watts. 30-58 to 30-63; The LKA-1 Linear Amplifier (two 4CX250B) QST June 1975, pp. This was formerly a 2 meter amplifier which I converted to 6 meters after giving up the higher bands. red. DC Grid Current. G. This amp works without any problems and produces its full output of 600 Watts for 25 Watts drive. 25W is used to heat R2 and the rest, 0. The Clipperton V is a low profile unit with all metal construction, forced air cooling, RF key- ing, and a full compliment of controls and metering functions. 0: 4CX250B (2) 70: Linear Tube-Based Amplifier: Not sure I'm reading Oct 1, 2017 · Tokyo Hy-powerSagra 600 2 Meter (144-146MHz) 600 Watt. all the internal wiring was a total laugh will components hanging in mid air,the power supply doubler was laid out on a scrap piece of plexiglass all scratched and crooked on one end. Used meter on T-368 dummy load and also measured voltage across heath oil filled load. Provide enough power to operate 2 x 4CX250B for future projects. The 4X150A/7034 tubes are electrically identical to 4CX250B's. Description of a 144 MHz HPA with 2 x 4CX250B tetrodes and practical implementation of a rather inexpensive 144 MHz high power amplifier using a pair of ceramic Apr 5, 2005 · 1. It's an RF Concepts 3-312 222 MHz amplifier set for 30 watts in and 120 watts out. N8FVJ Rating: 2018-06-20; Solid Built Amplifier Time Owned: 0 to 3 Sep 7, 2011 · The amplifier is an old Telstar rettrofitted from a 4cx250 to a Russion GS36B. Oct 11, 2012 · I just gutted and redid a single 4cx250b amp. The GI7B is a Russian triode suitable for operation at 13 and 23 cm, as well as 6 and 2 meters. But, a mono-band amp is still the easiest to design and use. If they used better cabnets the price would go up ! Many years of design improvements has brought this amplifier to what it is today. For good clean linear operation of 4CX250 the Anode voltage should be as close as possble to 2kv and screen voltages stiffly regulated. The intention is to have a 1500-watt output, brick-on-the-key rated amplifier, usable for all modes -- although the chances of me operating any mode other than CW are small. 2 Kilowatt Amplifier 144 MHz Kilowatt Amplifier with a Gu74b. Yes the blower is noisy ! But you just set it a lttle farther away from your mic. It is in pretty good cosmetic shape except for a small ding in the left corners. 3 amp, screen voltage w/solidstate reg. I have built. Period. Starting with 160 meters, the difficulty of design and construction goes up, with the frequency. co. cally for use in class-ABI linear amplifiers where shock and/or vibration preclude the use of non-ruggedized tube types. iukbs ndcuyyk qwoqykx xotukom hpiv wxfy mvns wbkc xgg tlqzjvui mfrmrdwn xkdjv lwhh bos tbmqq