2,359
edits
No edit summary |
No edit summary |
||
Line 16: | Line 16: | ||
The {{Title|General Radio 724-A Precision Wavemeter}} was introduced in {{Catalog J}} and remained available through {{Catalog K4}}. | The {{Title|General Radio 724-A Precision Wavemeter}} was introduced in {{Catalog J}} and remained available through {{Catalog K4}}. | ||
The Type 724-A is an absorption type wavemeter | The Type 724-A is an absorption-type wavemeter with a range from 17 kHz to 50 MHz using seven coils with an accuracy of ±0.25%. The primary application of the 724-A is oscillator and transmitter frequency measurement. | ||
The capacitor used is similar to the | The capacitor used is similar to the [[722-N|Type 722-N Precision Capacitor]]. It is connected to the inductor through a [[774|Type 774 coaxial connector]]. | ||
Resonance is achieved using one of three methods – absorption, reaction, or beat method. | |||
Using the panel galvanometer, the absorption method is employed. | |||
Regardless of the method, once resonance is achieved, it is a matter of using the correct chart for the coil in use to determine the frequency. | |||
Type 724-A was supplied as a collection of calibrated components sharing the same serial number, i.e. the capacitor, inductors, and calibration charts must have the same serial number to achieve the stated accuracy. | |||
Note: The instrument | The 724-A replaced the [[224-A|224-A Wavemeter]] with improved coils and a galvanometer replacing the thermocouple type indicator. | ||
The wavemeter was furnished with a wooden storage case, fitted with lock and carrying handle. | |||
This case has compartments for holding the capacitor, inductors, and calibration charts. | |||
The 724-A uses a 1G4GT/G triode vacuum tube, resulting in the need for a 1.5 V battery for the heater. | |||
Note: The instrument shown in the photos below uses a 1LE3 loctal battery triode. It appears to be a production change. | |||
==Specifications== | ==Specifications== |