An analysis of radio flutter in future communications

It is expected that future military operations will be extremely mobile. It is planned to provide for the Army full duplex communications while its subscribers are in motion. This will require the use of radio for serving the subscribers. Reception from or in a vehicle in motion is plagued by a malady known as flutter. It results in cyclical impairment of reception. It is caused by the varying field strength pattern generated on multiple path reception of the same radio signal. The audio signal level can be maintained by an AVC. The increase of noise level during operation of AVC can adversely affect the operation of system signaling. All sorts of schemes are being studied to overcome the effect of the flutter. In this paper the flutter effects on the communication system will be analyzed. The improvements resuiting from certain remedies will be predicted. Propagation data at 150 mc will be presented. Emphasis will be placed on the switched antenna type of space diversity reception. The value of this technique will be established by a brief discussion of the benefits that may be expected. Recent advances in the Solid State Field make feasible the design and construction of an applique unit which will assure us of benefits of space diversity reception at a relatively low cost. The design of antenna switching circuitry which operates on a programmed basis will be described. Problems generated by these techniques will be aired.