7.5 GHz bandwidth claim not substantiated by the data sheet

The statement amplifier for frequencies up to 7.5 GHz is not substantiated by the data sheet.

Could this be a misunderstanding based on the 7.5 MHz bandwidth specified there for a 450 MHz amplifier?

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Vielen Dank für den Hinweis, die Daten sind jetzt geändert.

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See also tube 7486. I'd thought only TWTs worked as amps up to 7.5GHz, for thermonic devices. But maybe these do go that high?

I've not read the data sheet, as it won't load, but found it elsewhere DOCTSF n° 88974

Tiny planar metal-ceramic triode intended for use as oscillator or as RF small-power
amplifier in the UHF range.
As oscillator the tube delivers about 450 mW at 450 MHz or 300 mW at 1200 MHz.
As class C RF power amplifier it can deliver 300 mW at 450 MHz. 11500 micromhos
transconductance, typical amplification factor 90.
6.3 V at 240 mA heater.
General Electric, July 1959, RMA record 2520.
 

The GE datasheet elsewhere (doctsf) has typical 450 MHz 450 mW and 1200 MHz 300 mW, which is more believable for the capacitances and construction. Basically a 1960s update of the glass acorn.

Specifies a minimum of 200 mW at 1200 MHz as an oscillator undfer special performance tests.

I'd suspect the entire family of devices is < 1.3 GHz, not the quoted > 3 GHz on RM.

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The parent device of this family seems to be the 6BY4, a planar UHF triode from 1955.

This record about a prototype L64  is also suspect. Klystrons, TWTs and Magnetrons up to 10.7 GHz in 1955, but I can't belive a ceramic or cerment planar triode above 1.5 GHz. I could of course be wrong.
My understanding, which could be in error, is that these ceramic planar tubes from mid 1950s to mid 1960s are RCA updating the glass Acorn 955 series started in 1935. The other direction of RCA was of course the Nuvistor in 1959, which hass similar frequency limits to the Acorns, but almost transistor (TO5 can) sized in a metal case. The Acorn type was hard to manufacture compared to later B7G devices. The Nuvistor seems to be different structure, but the 6BY4 family seem similar to Acorn types?


 
 

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See also the  British micropup, also maded by RCA in the 1940s. Here is the NT99, but some worked to over 900 MHz. Rather higher power and made obsolete for Radar by Magetrons.

The Magnetron is of course still in most kitchens at 2.5 GHz and 800W and is essentially a self oscillating diode.

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Hello Michael,

7486 was similar to 7077, same size, shape and interelectrode capacitance values. The only appreciable difference was in that the 7077 was proposed as signal amplifier while the 7486 was intended as oscillator or RF power amplifier and tested for pulse operation at 1.2 GHz. The GE type selection table in the TPD-6101 catalog of ceramic tubes and modules specifies 7.5 GHz as maximum frequency for both types even if the 7486 data sheet specifies its operation as oscillator at 1200 MHz.

Emilio

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