Bm technology single 4cx250b amplifier rooster cb radio connection. The tube is externally identical to the 4cx250b but contains rugged internal construction features amplification factor and cathode area have been increased over the basic 4cx250b to give higher transconductance and figure of merit. The 72034cx250b is designed to operate with a heater voltage of 6. Grid voltage is always zero, since grid voltage actually is gridtocathode voltage, and theyre tied together. T1,2 2 x tube 4cx150a, 4cx250b, 4cx250r, 4cx250f, srl460, re025xa the air outlet is through a ptfe chimney on top of each tube. The main category is rf power amplifier theory that is about designing rf power amplifiers. Hickok documentation, manuals, schematics, and catalogs. The 4cx250r7580w will replace the 4cx250b in equipments where the range of bias adjustment will tolerate this higher purveyance tube and where tuning range can compensate for the small differences in input and output capacitances.
Eimac 4cx250b 7203 power tetrode tube nos for sale online. I often found other factors effected tube life far greater, such as filament voltage management, cooling and by extension, cleanliness. Silver plated tubes may exhibit some silver tarnish which does not detract from performance. This link is listed in our web site directory since thursday oct 22 2015, and till today eimac 4cx250b has been followed for a total of 293 times. Circuit design and application information in this book are applicable to all eimac power grid tubes.
The 4x250b is capable of pro ducing 390 watts of output power at frequencies up to 175 megacycles, and at the maximum rated frequency of 500 megacycles a minimum of 225 watts may be obtained. Gu74b 4cx800a ceramic power tetrodes dxegu74b free. The performance characteristics of the 4cx800a allow its use as a high gain griddriven rf amplifier or as used in grounded grid service find gu74b 4cx800a ceramic power tetrodes dxegu74b and get. The 4cx250bm is a ceramicmetal, forcedair cooled externalanode tetrode with a maximum anode dissipation rating of 250 watts. Valve tubes itk51 fu3150s vacuum ceramic tube transmitting g5747 xh. This is a suitable replacement for any 6l6 tube type. Reference data for radio engineers, international telephone and telegraph corp. The 4cx250b qel2275 is designed to operate with a heater voltage of 6. And it will show more peak power than the b type tubes, as with the 250r. The 4cx250b is a pretty dirty ssb tube unless a complete modernization of the screen and bias supplies are done and still keep it around 600w for a pair but they are still no better than 12v ss amps. Detailed data sheets on the various tubes listed in this catalog are available upon request. A wonderful reference for anybody designing equipment with vacuum tubes. Amplification factor and cathode area have been increased over the basic 4cx250b to give higher transconduc.
The tube is externally identical to the 4cx250b but contains rugged internal construction features. Some tubes may show faint marks from the socket in our testing equipment. The base is a special version of the b8f because it has to incorporate the forced air system, a matching ceramic chimney was made for the base, and the control grid was connected to the central metal spigot. The 4cx250f is used in the sweep circuit of the 519. Tube 4cx250b or rohre 4cx250b id18711, transmitting tetrode, air cooled, special tubebase in general and uhf shown. The 4cx250b qel2275 has a maximum plate dissipation rating of 250 watts and a maximum inputpower rating of 500 watts. Stock setup may not turn down the tubes idle current far enough with an r installed.
Technical data the 72034cx250b and 86214cx250fg are ceramicmetal forcedair cooled, externalanode radialbeam tetrodes with a maximum plate dissi pation rating of 250 watts and a maximum inputpower rating of 500 watts. Eimac 72034cx250b high power rf pa tube, new is open box 5 out of 5 stars 2 product ratings 2 product ratings eimac 72034cx250b high power rf pa tube, new is open box. The 4cx250b7203 is designed to operate with a heater voltage of 6. Cpieimac is a leading manufacturer of power grid tubes covering a wide range of applications including broadcast, industrial and scientific. When the tube is operated at maximum, corporation of america electron tube division harrison, n. The external dimensions of each compartment are 300 x 175 x 58 mm. Description of a 144 mhz high power amplifier for 2 x 4cx250b. Eimac power grid tubes quick reference 116 pages 1975. This is a suitable replacement for any 6g6gvt198a power pentode.
A comparison of the published orginal eimac 8875 data and the published svetlana 4cx400 data sheet. Imaicho 12212 gojo, nara prefecture, japan name matsuda tomotaka. Assuming that the real part of the impedance mainly is caused by electron transittime losses, it could be extrapolated to about 0 ohms at 50 mhz. Tube 4cx250f or rohre 4cx250f id22418, transmitting tetrode, air cooled, special tubebase in general and shown. Add to compare the actual product may differ from image shown. Operation is very simple, the only controls are tune, load, bandswitch, meter and bias set. Dx engineering gu74b 4cx800a ceramic power tetrodes are highperformance ceramic metal tetrodes with a plate dissipation rating of 800 watts. Some people complain that rebuilds dont last as long, or only last half as long as the new tubes.
Various pdf files containing eimac tubes information. This tube utilizes a ruggedized internal structure and. The input impedance of the linearbiased 4cx250b has been modelled by dk1of ukwberichte 41977 and is about ohms in parallel with 20 pf at 144 mhz. The 4cx350a8321 has a maximum plate dissipation of 350 watts and is intended for class ab audio or rf amplifier service. The 4cx350a has a maximum plate dissipation of 350 watts and are intended for class ab audio or rf amplifier service.
Overview of tasks in performing the conversion, five specific needs must be addressed. Otherwise, the two tube types have identical charac 7203 4cx250b 7204 4cx250f radialbeam power tetrode teristics. Herein you will find a collection of vintage engineering texts, vacuum tube datasheets, and other obsolete information, presented free of charge and without annoying advertisements. Signal dc gridno, corporation of america electron tube division harrison, n. With the naming conventions of ceramic tubes, we can tell quite a bit about the unit without even looking at the data sheet. If you can score a pair of good 4cx350fj8904s then you will have excellent imd with the ps changes. Designers of new equipment are urged to contact eimac to get. Buy your 4cx250b from an authorized richardson electronics distributor. The 7203 4cx250b is designed to operate with a heater voltage of 6. The 4cx250b m is a ceramicmetal, forcedair cooled externalanode tetrode with a maximum anode dissipation rating of 250 watts. The 4cx250f is the same as the 4cx250b 7203, but with a 26. Rf amplifier up to 175 mhz, 4cx250b datasheet, 4cx250b circuit, 4cx250b data sheet. You can run a 4cx250b type tube just like that, with about 75w drive, to 375w output without exceeding the ratings.
For specific ratings, operating parameters and information dealing with a particular tube type, refer to the technical data sheet for the tube in question. S a the 4x250b is a compact, forcedair cooled, externalanode radialbeam tetrode with a maximum plate dissipation rating of 250 watts. The 4cx250b m is intended for use in applications where tight control of electrical specifications is required and replaces the 4cx250b in all applications. It is playing in the vacuum tube, such as 4cx250b and 4x150a d. Type 8930 is a 4cx250r with a largerdiameter 350watt rated radiator ring. Eimacs book on the care and feeding of power grid tubes says that extra cooling air pushed thru the tube is a good thing and will not hurt anything. It was used in the ww2 up to about 1980 and production was fully automatic carousel material in tube out. June 1975 optimistic, experiments conducted by the author indicate that if tank circuit conditions are approxi mately correct, efficiency is very good. The 4cx250b is designed to operate with a heater voltage of 6. This amplifier was constructed as a portable amplifier for use on 6 meters.
The 4cx250b7203 is primarily used in broadcast applications. The 4cx250bm is intended for use in applications where tight control of electrical specifications is required and replaces the 4cx250b in all applications. I heard someplace that the 4cx series went bad with run time, the inside of the tube gets coated with stuff that boils off the cathode, then they short out. Comprehensive transmitting tube data 1988 handbook base diagrams and data. It was originally designed as an rf power amplifier tube for transmitters and requires forced air cooling. Mar 23, 2015 it is playing in the vacuum tube, such as 4cx250b and 4x150a d. A condensed semiconductor brochure is also available upon request.
Bill beech, nj7p has a tube database on his web site comprehensive transmitting tube data 1988 handbook base diagrams and data. Data conversion development kits interface communications development kits. Rebuilt tubes were about half the cost of brand new ones. These were often used for driver tubes in fm broadcast transmitters. Ian white, gm3sek, sells kits for tube control and protection. They are of particular interest to hams building tetrode amplifiers, which have more complicated biasing circuits than grounded grid triodes. Jtg built 4cx300a two tube linear amplifier duration. Cpi, alldatasheet, datasheet, datasheet search site for electronic components and semiconductors, integrated circuits, diodes, triacs, and other semiconductors. About eimac 4cx250b the resource is currently listed in in a single category. I did this with the use of an mfj antenna analyzer which i connected to the output.
The chimney has to fit tight on both tube and top cover. The 4cx250b7203 is an fac tetrode manufactured by cpieimac. Limited 90 day warranty, limited quantity available, new old stock, not for export. The 4cx250r7580w will deliver more output in most linear amplifiers. Bill beech, nj7p has a tube database on his web site. Input and output anode compartment are made from 1 mm aluminium sheets. With no signal, very little plate current flows because screen voltage is zero. Jtg built dual 4cx250b base linear amplifier 110v duration. The 4cx250b7203 has a maximum plate dissipation rating of 250 watts and a maximum input power rating of 500 watts. The eimac 4cx250bm is a ceramicmetal, forcedair cooled externalanode tetrode with a maximum anode dissipation rating of 250 watts. The 4cx250b is the classic rf power tetrode valve for vhf and low uhf applications. This was the most sold transmitting tube because it was cheap.
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