OPERATING INSTRUCTIONS

SKY CHAMPION

Model S-20

THE SKY CHAMPION

the hallicrafters inc.
2611 INDIANA AVENUE
CHICAGO

GUARANTEE

This receiver is guaranteed to be free from any defect in workmanship and material that may develop within a period of ninety (90) days from date of purchase, under the terms of the standard guarantee, as designated by the Radio Manufacturers Association. Any part or parts that prove defective within this period will be replaced without charge when subjected to examination at our factory, providing such defect, in our opinion, is due to faulty material or workmanship, and not caused by tampering, abuse or normal wear. All such adjustments to be made FOB the factory.

Should this receiver require any adjustments, your dealer or distributor has complete technical service information, or the factory will be glad to assist you in any problem direct.

Should it be necessary to return any part or parts to the factory, a "Return Material Permit" must be obtained in advance by first writing the Adjustment Department, who will issue due authorization under the terms of the guarantee.

The Hallicrafters, Inc., reserve the right to make changes in design or add improvements to instruments manufactured by them, without incurring any obligation to install the same in any instrument previously purchased.

All Hallicrafters receivers are built under patents of Radio Corporation of America and Hazeltine Corporation.

THE HALLICRAFTERS TYPE SM 18 "S" METER

The SM18 is a signal strength indicator designed as an accessory for the Sky Champion II. It connects via a socket on the receiver's chassis. The meter features an indirectly illuminated scale calibrated in "S" units for convenient checking of incoming signal carrier strength. A zero setting resistor is located on the rear of the meter case. A three-foot connecting cable allows flexible placement. The SM18 meter was available for $10.00 through Hallicrafters distributors.

A simplified diagram shows the meter's internal components: a 0-1 MA meter, a pilot light, and connections for B+, Screen, Filament, and B-. It also shows input terminals labeled 25M, 10M, and 20M, and output terminals labeled 3, 04, and 20.

SKY CHAMPION MODEL S-20 RECEIVER DETAILS

General Description

The Sky-Champion is an 8-tube band superheterodyne receiver covering the following frequencies:

BAND	COVERAGE
1	540 KC TO 1,800 KC
2	1.70 MC TO 5.75 MC
3	5.62 MC TO 18.40 MC
4	17.00 MC TO 44.00 MC

Separate coils are used to cover each band. Inductive coupling to the antenna permits maximum transfer of signal energy from each separate primary to the particular secondary coil in the circuit. Unused coils are shorted. Calibration on the main dial is in kilocycles on Band #1 and in megacycles on Bands #2, 3, and 4.

Dial Mechanism

The new Sky-Champion dial mechanism is of particular importance for enjoying the operation of this receiver. Band-spreading of all frequencies covered by the Sky-Champion allows easier tuning as well as a ready means of logging stations. The fly-wheel equipped mechanism affords effortless tuning over long periods of time.

Send-Receive Switch

The send-receive switch enables the operator to make the receiver inoperative temporarily during stand-by periods. Should the receiver be used in conjunction with a transmitter, this feature will prove valuable.

Antenna Connection

On the back of the chassis, you will find the Antenna, Doublet, and Ground terminal strip. A conventional single wire antenna should be connected to A1, and the jumper between A2 and G left connected. A 75-foot piece of #14 enameled wire, insulated and suspended in the clear, is recommended for this type of antenna. If a doublet antenna is used, the two wires of the lead-in are connected to A1 and A2, and the jumper between A2 and G removed. A ground can be connected to the G terminal with either type of antenna. It is suggested that a ground be left off the receiver only if in so doing the performance of the receiver is improved. There are so many different versions of antenna systems that users wishing to experiment with various types should first familiarize themselves with the antenna section of the A.R.R.L. Handbook.

Operation

Unless otherwise specified, the receiver is designed to operate on 110-120 Volts, 50-60 cycle alternating current. Plug the power cord into the socket and turn the control marked "Audio Gain" to the right. The receiver will then be connected to the power line. After the required few moments have passed necessary for the tubes to reach operating temperature, the unit can be placed in operation.

Band Switching and Reception Peculiarities

The "BANDS" switch should be placed on Band #1, or Standard Broadcast, when the receiver is first used. After you have familiarized yourself with the operation of the receiver on that band, the 3 higher frequency ranges may be tried.

It may be advisable to call to your attention the peculiarities of reception of the 4th band. Frequencies covered by this band are usually heard only during the daylight hours. Additionally, skip conditions being favorable, you will be able to hear only signals which have the point of their origination removed by at least 1,500 miles from your location. Reception on this band is very freaky and rapidly affected by quickly changing high frequency conditions.

Automatic Volume Control (A.V.C.)

The A.V.C. (Automatic Volume Control) switch provides optional use of A.V.C. When receiving music or voice signals, it is advisable that the switch be in the "ON" position. When receiving code transmissions, the switch should always be in the "OFF" position.

Beat Frequency Oscillator (B.F.O.)

The B.F.O. switch must be in the "ON" position to obtain the necessary beat note for the reception of code signals. Using the B.F.O. will be helpful in locating the carriers of distant and possibly weak broadcasting stations. Once located, the B.F.O. should be turned off, or the whistle will interfere with reception.

Pitch Control

The pitch control, when the B.F.O. is "ON", will allow you to vary the frequency of the resultant beat note to one that is most pleasing to you.

Headphone Jack

A headphone jack is mounted in an accessible position on the front panel of the Sky-Champion. Any type of headphones can be used because no direct current flows in the headphone circuit. When the phones are plugged in, the loud speaker is automatically disconnected.

"S" Meter Connection

On the back of the chassis, you will find a socket into which you can plug a Type SM-18 carrier level indicator. When this meter is used, it will be necessary to advance the R.F. Gain control on the receiver as far as it will go to the right. Doing this will operate the switch which is mounted on the back of this control. Additionally, the A.V.C. switch should be in the "ON" position to properly connect the meter in the circuit. This meter is available through the dealer from whom you purchased your receiver.

PARTS LIST

No.	Ohms	Wattage	Parts No.
R1	10,000		25-029
2	100,000	1/3	20-093
3	350		20-120
4	100,000		20-093
5	600		22-125
6	30,000	1/3	20-021
7	300		20-021
8	20,000		20-072
9	300		20-021
10	250,000		20-099
11	500,000		25-031
12	1,000,000	1/3	20-108
13	100		20-009
14	25,000		20-073
15	100,000	1/3	20-093
16	50,000		20-084
17	500,000	TONE CONTROL	25-018
18	500		20-025
19	20,000		20-070
20	25,000		20-073
21	100,000	1/3	20-093
22	10,000		20-061
23	50,000	1/3	20-084

No.	Capacit y	Type	Voltage	Parts No.
C1	408 MMFD	MAIN		48-022
2	10 MMFD	TUNING	200	41-004
3	.05 MFD	MICA	200	41-004
4	.05 MFD		200	41-004
5	.05 MFD		200	41-004
6	10 MMFD	MICA		40-021
7	25 MMFD			40-024
8	.05 MFD		200	41-004
9	.002 MFD			40-013
10	.05 MFD		200	41-004
11	.05 MFD		400	41-005
12	.02 MFD		200	41-002
13	100 MMFD			40-007
14	.05 MFD		200	41-006
15	100 MMFD			40-007
16	.05 MFD		200	41-004
17	.05 MFD		400	41-007
18	.05 MFD		400	41-005
19	.05 MFD		400	41-005
20	.00025" MFD			40-024
21	.01 MFD		200	41-000
22	.01 MFD		400	41-007
23	.01 MFD		600	45-002
24	.01 MFD		600	45-002
25	.01 MFD		450
26	.01 MFD		450	42-021
27	10 MMFD	TWISTED PAIR	400	41-007
28	.01 MFD		400	41-001
29	.01 MFD		400	41-001
30	.01 MFD		400	41-001
31	250 MMFD	MICA		40-024
32	25 MMFD	MICA		48-021
33	100 MMFD	MICA		40-007
34	.002 MFD	PAD		40-013
35	430 MMFD	PAD		44-025
36	1,300 MMFD	PAD		44-024
37	2,100 MMFD	PAD		44-025
38	100 MMFD	MICA		40-007

SW	Description	Type
1	A. V. C.	SPST
2	B. F. O.	SPST
3	AC ON-OFF (ON TONE CONTROL)
4	PITCH CONTROL
5	SEND - RECEIVE	SPST
	EXT "S" METER (ON RF GAIN)

SCHEMATIC DIAGRAM

The schematic diagram for the Sky Champion Model S-20 provides a detailed electrical blueprint of the receiver. It illustrates the interconnections between the eight vacuum tubes (6K7, 6L7, 6J5G, 6K7, 6Q7Q, 6F6G, 6J5G, 80), identifying their roles such as RF stage, detector/mixer, IF amplifier, audio output, and rectifier. The diagram maps out the signal flow, power supply connections (B+, B-), and control circuits, including the band switch, AVC, BFO, and pitch control. It also shows connections for external components like the antenna, ground, speaker, headphones, and the optional SM-18 'S' meter. Component values for resistors and condensers are indicated throughout the diagram.