The R.L, Drake model TR-4 is an 80 through 10 meter amateur band transceiver. The modes of operation are SSB, AM and CW. Full coverage on all amateur bands, 10 through 80 meters is accomplished in seven 600 kc ranges which is as follows, 3.5 to 4.1 mc, 7.0 to 7.6 mc, 13.9 to 14.5 mc, 21 to 21.6 mc, 28 to 28.6 mc, 28.5 to 29.1 mc and 29.1 to 29.7 mc.
Upper sideband and Lowe sideband selection is accomplished by switching between two 9 mc crystal lattice filters which have a 2.l Kc passband. The TR-4 transceiver is loaded with features. These features include a VOX circuit for SSB and AM, diode detection for AM, shifted carrier CW, automatic transmit receive switching on CW, built in CW side tone, separate RF and AF gain controls, a solid state VFO with linear permeability tuning, transmitting and receiving AGC indicator, a plate ammeter and RF output indicator, an adjustable pi-network output, and built in crystal calibrator. The TR-4 uses two 6JB6 sweep tubes for the finals.
Due to the 300 watt P.E.P. input rating, the TR-4 will require a power supply capable of low voltage at high current with very good dynamic regulation. The voltage and current requirements are as follows: 650 volts at 300 ma average and 500 ma maximum with 10% regulation from 100 ma to 500 ma and a maximum ripple of less than 1%. 250 volts at 175 ma with 10% regulation from 150 ma to 180 ma. This includes the effect of the 650 volt supply change if both voltages are obtained from the same transformer. Maximum ripple must be less than 1/4 %. Also needed is a -45 to -65 VDC adjustable filtered bias into 33 KOhm load and 12.6 Volt AC or DC at 5.5 amps.
The TR-4 has 20 tubes including the voltage regulator, four transistors and nine diodes.
The addition of the accessory RV-3 or RV-4 remote VFO speaker combination enables the operator to receive, transmit, or transceive throughout the band being used without disturbing the TR-4 tuning dial. This is useful for working DX stations that are operating outside of the US phone bands, or for working near your own frequency in search of a clear spot under crowded band conditions.