. The Bell System technical journal . ed, but the original program hadadvanced beyond the stage at which it could be changed. The improve-ments in design of the double length 718AY-EY type magnetron resultedin the 720A-E series. An external view of the 720A-E magnetron is shown in Fig. 62. A cut-away model is shown in Fig. 63 in which may be seen the nature of the 304 BELL SYSTEM TECHNICAL JOURNAL resonator system, straps, cathode, and output circuit. In Table II aregiven dimensions and other data concerning these magnetrons. The resonator system has eight hole and slot type cavities. Its anod
. The Bell System technical journal . ed, but the original program hadadvanced beyond the stage at which it could be changed. The improve-ments in design of the double length 718AY-EY type magnetron resultedin the 720A-E series. An external view of the 720A-E magnetron is shown in Fig. 62. A cut-away model is shown in Fig. 63 in which may be seen the nature of the 304 BELL SYSTEM TECHNICAL JOURNAL resonator system, straps, cathode, and output circuit. In Table II aregiven dimensions and other data concerning these magnetrons. The resonator system has eight hole and slot type cavities. Its anodelength is 4 cm., double that of the 706AY-GY. It is strapped with doublering shielded straps of special design which could be stamped out of sheetcopper and oven brazed in position in a wide ledge trepanned around theinteraction space into the ends of the anode block. These straps wereeasier to control in dimensions than the echelon straps, used in early models, which had made necessarj^ the development of a pretuning. Fig. 63—A view of a cut-away 720A-E magnetron (1000 kw., -^2800 mc/s) showing thelarge cathode end disks and the impedance transformer sections in the output circuit. technique. The large number of wire straps used had made it impossibleto predict from visual inspection that a given anode would eventually oscil-late at a specified wavelength. The straps were adjusted manually to bringthe frequency of resonance determined before sealing and pumping into therequired range. These heavily strapped models operated at efficiencies upto 65 per cent, but their initial operating wavelengths were near 13 high operating efficiency was achieved at the required wavelength byscaling the structure. The increase in magnetic field required by the scalingwas achieved without increase in magnet size by incorporation of steel disksin the end covers of the magnetron. The new stamped straps requiredconsiderably less manipulation during pretuning than the echel
Size: 1897px × 1317px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
