LOW LEVEL TRANSMITTER-EXCITER
Abstract:
The development is presented of 8-watt, amplitude-modulated, single-channel radio-telephone transmitters capable of operation in the VHF and UHF ranges. The single channel crystal-controlled transmitter can be set to any desired frequency in the range of 118 to 152 mc TV-24 and 225 to 400 mc TU-5. The transmitters may be operated either as a low-powered transmitter or as exciters capable of driving a high-powered linear amplifier. The transmitter circuitry involves specialized packaging of conventional transmitter components, an audio-modulator, a directional coupler, and a low-pass filter. The transmitters are designed for the attainment of high operational stability, long operating life, ease of maintenance and reduced cross-modulation. The transmitter-exciters exhibit VHF stability. Frequency stability for the TV-24 is .00015 and the TU-5 stability is .00013. Two major development goals were achieved 1 the reduction of cross-modulation products by use of low-level modulation and linear amplification, and 2 the development of compact accessible assemblies which take advantage of the latest advances in the state-of-the-art. The complete unit occupies only 3 12 inches of vertical panel height and requires no forced air cooling. Author