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Title: revisited old Hallicrafters module A-801 P/N 150-000407 after almost a decade Post by: Opcom on October 06, 2020, 02:32:32 AM This was listed that long ago in the for sale, some oddball Hallicrafters part, and forgotten about. Found it languishing in the garage at the back of a shelf and thought to at least do the schematic and look up the tubes. It uses ten 5702WA tubes, These are the rugged subminiature "CK" style Raytheon made.
The module looks like a broadband amp with gain enough for an antenna preamp, but there's no telling what it's from. Simple hookup, I think the B+ is somewhere between 70V and 120V, 50-100mA. Bias maybe 2-3V, class A. Apparently 120 Ohms in and out. No one has ever been able to ID this little 11"x1.5"x3" module. Anyway, the circuit's very cool and here's the schematic and pics, since some time was spent on it today. It has a better protected location now, in a drawer at least. No time to hook up and try it for bandwidth, too many other things going on. I like weird stuff I guess. Title: Re: revisited old Hallicrafters module A-801 P/N 150-000407 after almost a decade Post by: WBear2GCR on October 11, 2020, 05:27:44 PM No sketch-a-matic... two copies of the same pic + tube manual pages. Neat tube. Looks g3 works in an interesting way... _-_-bear Title: Re: revisited old Hallicrafters module A-801 P/N 150-000407 after almost a decade Post by: Opcom on October 11, 2020, 10:37:49 PM Hallicrafters distrib amp module A-801 PNr 150-000407.pdf (609.82 KB PDF file of Schematic from LTspice. Hallicrafters distrib amp module A-801 PNr 150-000407_1.jpg (557.27 KB JPG image: photo of the module. Hallicrafters distrib amp module A-801-tubes-5702WA.pdf (405.31 KB Data sheet for the 5702 tube. CK60Y471Z capacitors - only this one kind is used. 470pF obviously, but deserved to be looked up in case of being something special. Any decent disk should do. MIL-C-11015 Aerovox 470pF +100/-0% 500V TC: X5U (+22 to -56% capacitance change from -55 to +85 deg C. (EIA-198)) 1969 Radio Electronic Master p.142 http://www.calramic.com/Design/Assets/PDF_files/AN110-Voltage-Temperature-Coefficient.pdf Title: Re: revisited old Hallicrafters module A-801 P/N 150-000407 after almost a decade Post by: WBear2GCR on October 13, 2020, 12:43:34 PM Twilight Zone stuff... clicked on the the pdf and got the jpg last time!
Or so I thought... Anyhow, tnx for the sketch-a-matik! Title: Re: revisited old Hallicrafters module A-801 P/N 150-000407 after almost a decade Post by: Opcom on October 14, 2020, 12:42:49 AM That's me trying to re-use file names when extensions are different. When same, a -1,-2 etc is used. makes it much easier to search through >500K files LOL. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
I guess the eventual thing to do will be to test it. Might take a long time to get around to it. Distributed amp gain (for one that works..) is apparently: gm = transconductive gain of each device Zo = output impedance seen by each device = half the characteristic impedance of the transmission line. n = is the number of stages. Av = integer voltage gain So that the overall voltage gain of the DA is: Av = ½ n·gm·Zo gm = 5000 uMHOS Zo = 120 Ohms n = 10 Av = ½ n·gm·Zo = Av 0.5 * 10 * 5000 * 120 = 3000000 ?? no not uMhos, but maybe Mhos.. 0.5 * 10 * .005 * 120 = 3 (20log 3 is 9.5dB) I don't know how to design or evaluate -by-numbers this kind of thing. I just like Twilight Zone. |