62S-1 Transverter

THE COLLINS 62S-1 TRANSVERTER

The Collins 62S-1 permits you to enjoy operation on either 6 or 2 meters by simply snapping a switch. No cable patching is required when changing from the HF to VHF frequencies. The self-contained unit, using the exciter's high voltage, supplies a 3-5 db receiver noise figure and transmitter input of 160 watts PEP. It can be used in any operational mode, as determined by the companion receiver and transmitter.

Reflecting Collins emphasis on system engineering and flexibility in amateur equipment, the 62S-I is designed for use with the S/Line, KWM-2 and KWM-1; however, it will convert signals from most amateur equipment operating in the 14.0-14.2 mc range.

The Collins 62S-1 assures you of outstanding performance with the following features:

EXCELLENT FREQUENCY STABILITY with carefully designed oscillator circuits using 0.005% crystals.

LINEAR DIAL CALIBRATION provides equivalent of 21 feet of bandspread on both 6 and 2 meters.

SPURIOUS RADIATION meets FCC, Part 15, Sub Part C, regulations covering all very high frequency receiving equipment. Low CROSS MODULATION resulting in excellent rejection of strong adjacent signals is provided by three tuned circuits in the first RF stage. These circuits are retuned every 200 kc. EASE OF OPERATION is assured when used in conjunction with the Collins S/Line on all amateur bands between 80 and 2 meters with no connecting or disconnecting of enables. CHOICE OF MODES includes SSB, CW or AM, as determined by associated transmitter and receiver.

The 62S-1 offers complete coverage of 49.6-54.2 mc and 143.6-148.2 mc frequency ranges in 200 kc increments using an oscillator-amplifier injection system for frequency conversion with 23 crystals (MARS band crystals not furnished) which can be selected for heterodyning down to 14.0-14.2 mc on receive, and up from 14.0-14.2 mc on transmit.

The 62S-1 Converter is finished in light gray enamel with the front panel chemically etched to simulate leather and is compatible in appearance and styling with other Collins S/Line units.

62S-1 SPECIFICATIONS


FREQUENCY RANGE: 49.6-54.2 mc; with crystals furnished:
    6 meters -  50-54 mc in 200 kc increments.
    2 meters - 144-148 mc in 200 kc increments.

MODE:  SSB, CW, AM or RTTY on transmit and receive,determined by
    exciter and receiver.

TYPE OF SERVICE: Attended operation. Continuous on receive and transmit.

POWER REQUIREMENTS: 115 v ac, 50-60 cps at approximately 75 watts.
    Power can be delivered by an external power supply which must
    furnish 800 v dc at 220 ma for the PA plate circuit:
    275 vdc at 20 ma for the PA screen circuit.

PLATE POWER INPUT: 160 watts.

POWER OUTPUT: 65 watts PEP minimum into a 50 ohm load.

NOISE LEVEL: 40 db below rated PEP output.

HARMONIC AND OTHER SPURIOUS RADIATION: Oscillators and mixer products at
    least 60 db below PEP. Second harmonic at least 35 db below PEP.

AMBIENT TEMPERATURE RANGE: 0 -50 C.
AMBIENT HUMIDITY RANGE: 0%-90%.
PROTECTIVE DEVICES: Primary fusing in power supply.

SIZE: With feet - 14-3/4" W, 7-3/4" H, 13" D.

WEIGHT: 25 Lbs.

FREQUENCY STABILITY: 0.005% crystals are used throughout in the 62S-1.

OUTPUT IMPEDANCE: Variable; 50 ohms nominal, capable of matching 2:1 SWR.

SENSITIVITY: 2 meters - 1.2 uv maximum for 10 db S+N/N using 3 kc audio
    bandwidth (NF approximately 4);
             6 meters - 1.3 uv maximum for 10 db S+N/N using 3 kc audio
    bandwidth (NF approximately 4).

SPURIOUS RESPONSES: At least 50 db below a 1 uv desired signal level.
    Image rejection greater than 100 db on 6 meters.
    Greater than 60 db on 2 meters.

Under the hood...

62S-1 CIRCUITRY

General

The 62S-1 VHF Converter is a 6- and 2-meter transmitting and receiving converter covering the ranges of 49.6 to 54.2 mc and 143.6 to 148.2 mc in 200-kc increments. The associated h-f transmitter and receiver must cover the range of 14.0 to 14.2 mc.

The transmitter portion of the 62S-1 consists of five stages: a mixer, V1, in which the h-f exciting signal is converted to the vhf operating frequency; three linear voltage amplifiers, V2, V3, and V4; and a linear power amplifier, V5, operating in class AB1. Plate voltage is removed from the mixer and the first voltage amplifier while receiving. The receiver portion consists of a triode r-f amplifier, V7, and a triode mixer, V8, to convert received vhf signals to the h-f receive frequency. Internal relays ground the r-f amplifier grid and remove plate voltage from both the r-f amplifier and the mixer while transmitting.

Injection voltage for both the transmitter mixer and the receiver mixer is supplied by an oscillator-amplifier system, V6, V9, and V10. The crystal oscillator, V6, uses 23 crystals spaced 200 kc apart to provide a total range of 4.6 mc on either 6 or 2 meters. For 2-meter operation, a second crystal oscillator is switched into the circuit, and the 94- mc output from this oscillator is mixed with the output of the first crystal oscillator to provide the required injection frequencies.

Transmitter Circuits

The net inductance of L1 in series with L2 is parallel tuned to the 6-meter band by the combination of C1, C2, and circuit capacitance. Tuning within the band is done by varying the inductance of L2 which consists of a circular ring with a rotating wiper arm. When operating on 2 meters, C2 is switched out of the circuit, L3 is switched in parallel with L1, and L4 is switched in parallel with L2. This reduces the net inductance of the circuit and the inductance range of L2 to provide the proper LC ratio and tuning range for 2-meter operation. The PA plate circuits operate on the same principle with slight differences to accommodate PA operating parameters. The PA tank circuit is resonated on 2 meters by the output capacitance of V5, the PA tube. A trimmer to provide additional capacitance is switched into the circuit on 6 meters. Double contacts are used on the PA bandswitch wafer to reduce inductive effects and to handle the circulating r-f current. Link output coupling is used with a series variable capacitor for loading adjustments.

The power amplifier stage uses a 7034/4X150A tube which has an external anode requiring forced-air cooling. With the air supply provided in the 62S-1, plate dissipation should be held to a maximum of 120 watts. The PA grid circuit includes an alc rectifier consisting of diodes CR1 and CR2 connected as a half-wave doubler. An external load resistance of approximately 2 megohms is required, and usually is part of the h-f exciter alc circuit.

Receiver Circuits

Triode tubes are used in the r-f amplifier and mixer stages to minimize noise. The type 6ER5 tube used in these stages employs a partial shield between grid and plate to reduce grid-to-plate capacitance, thereby easing neutralizing requirements. Neutralization is used only on 2 meters, and there the principal function is to obtain a lower noise figure. An r-f gain control is included in the r-f amplifier cathode circuit so that the gain can be reduced when extremely strong unwanted signals are present near the desired signal frequency. Four tuned circuits in the mixer plate circuit provide a uniform response across the i-f output range, but response outside the passband is rapidly attenuated to minimize spurious responses.

The vhf tuned circuits and bandswitching in the receiver portion function in essentially the same way as those in the transmitter. An additional contact is used on bandswitch wafers in Z6 and Z7 to switch the neutralizing coil, L36, into the circuit on 2 meters. The variable inductor rings, illustrated by L2 in figure 3-2, are ganged to the main dial so that the 62S-1 receiver tuning tracks with the 200-kc band selected on the dial. This eliminates the need for broadband r-f circuits and provides a significant reduction in cross modulation over an equivalent broadband system.

Frequency Conversion System

An oscillator-amplifier system provides injection frequencies for frequency conversion. The system consists of the master oscillator subunit, a second stage which functions as an amplifier on 6 meters and as an oscillator- mixer on 2 meters, and a third stage which is an injection amplifier on both bands. The second and third stages are located in the receiver subunit

The master oscillator, V6, is crystal controlled using 23 selectable crystals to provide output frequencies from 35.6 to 40.0 mc in 200-kc steps. This frequency range provides transmitter output in the 6-meter band when mixed additively with 14.0- to 14.2-mc output from the exciter. A difference mix in the receiver mixer, V8, converts received 6-meter signals to the h-f range. Tube V10 and the pentode section of V9 are used as buffer amplifiers. On 2 meters, the two sections of V9 function as a 94-mc crystal-controlled oscillator. The pentode section also serves as a mixer. Output frequencies from the master oscillator are mixed additively with 94 mc to produce injection frequencies ranging from 129.6 to 134.0 mc. These injection frequencies then are used to heterodyne the h-i excitation to 2-meter operating frequencies and to convert received 2-meter signals to the h-f range.

Tuned circuits are used in the plate circuits of both crystal oscillators, V6 and V9, and the injection amplifier, V10. The plate circuit of V6 uses 23 selectable coils which are mounted on a turret. The appropriate coil is switched into the circuit in conjunction with the crystal selected. Both the turret and the crystal selector switch are controlled by the main selector. A double-tuned circuit, Z10, is switched into the pentode plate circuit of V9 on 2 meters to suppress unwanted mixing products. The inductor rings of Z10 are ganged to the main dial for in-band tuning. Switch sections S11, S12, and S13 are ganged to the bandswitch. A parallel-tuned trap, FL2, provides added attenuation to spurious products on 2 meters.

The basic functions of the 62S-1 control circuits are to provide compatible operation with h-f exciter vox and control circuits and convenient switching from h-f to vhf. For vhf operation, the following switching is done by the 62S-1 function switch in VHF TUNE and VHF OPR positions:

Screen voltage is switched from the exciter PA to the 62S-1 PA by S15B-front.

Exciter vox control circuits, which must furnish a ground to transmit, are connected via the HF ANT. RELAY IN jack and S15B-rear to the coil of relay Kl which is connected in series with the coil of K3. Plate voltage is connected to the opposite coil terminal of K3 via S15A-rear. Keying the exciter then keys the 62S-1 also.

The HF RF IN jack is connected to the 62S-1 receiver output circuit by S15A-front. Converted vhf signals are routed to the h-f receiver via this jack and the h-f antenna changeover relay (built into Collins exciters).

The keying circuit to the HF ANT. RELAY OUT jack is disabled by S15B-rear so that the associated h-f linear amplifier, if used, is not keyed by the h-f exciter control circuits when operating vhf.