The manual for the Hammarlund Comet "Pro" high-frequency superheterodyne receiver provides detailed instructions on setup, operation, and troubleshooting, including information on power supply options, selectivity, sensitivity, and noise reduction. It also describes the tuning system, coil configurations, and intermediate frequency adjustments necessary for optimal performance across a wide frequency range.
Manual Overview
The Hammarlund Comet Pro is a high-frequency superheterodyne receiver designed for professional and advanced amateur use, covering frequencies from 1.2 to 20 MHz. It emphasizes high sensitivity, low noise, and selectivity. The receiver operates on alternating current, offering convenience and quiet operation comparable to battery-operated models. The intermediate frequency is set at 465 KHz to balance selectivity and minimize image interference. For troubleshooting, technicians should use a DC voltmeter with at least 1000 ohms per volt resistance to check voltages at various terminals, ensuring they match specified values. Calibration involves tuning a steady carrier signal and adjusting intermediate frequency tuning condensers for peak voltmeter readings, with careful attention to maintaining the main tuning dial position. The receiver uses interchangeable plug-in coils for frequency range adjustments, with each set covering a two-to-one frequency range. These coils are mounted in Isolantite sockets for stability and efficiency, and shielded to prevent electromagnetic interference.
Quick Issues Covered
- Diagnose power-up failures with voltage divider terminal checks.
- Adjust I.F. alignment using voltmeter for peak tuning.
- Trace circuits using detailed schematics for coil connections.
Overview
The Hammarlund Comet “Pro” is a high frequency superheterodyne receiver designed for professional operators and advanced amateurs. It covers a frequency range from 1.2 to 20 megacycles and is suitable for receiving both code and voice radio signals, as well as for experimental and research work. The receiver features high sensitivity, low noise level, and great selectivity. It operates on alternating current and includes a unique tuning system with interchangeable plug-in coils for different frequency ranges. The manual provides detailed descriptions of these features and instructions for adjusting I.F. alignment and oscillator frequency.
Specifications
- The HAMMARLUND Comet "Pro" is a high frequency superheterodyne receiver.
- Frequency range: 20,000 K.C. to 1200 K.C.
- Intermediate frequency: 465 K.C.
- Sensitivity: 1/10 micro-volt input for C.W. code signal at 20 words per minute.
- Interchangeable plug-in coils for frequency range shifting.
- Coils cover range: 15 to 250 meters.
- Coils wound on extruded Isolantite forms, 1 1/2” in diameter.
- Tuning condensers cover frequency range of approximately two to one.
- Four sets of coils used for ample overlap.
- Selectivity: Over-all response curve averages 30 K.C. wide at 10,000 times input.
- A.C. operation decided upon for power supply.
- Litz wound intermediate coils used.
- Voltage readings for checking:
- – Top terminal of voltage divider: 250
- – Second terminal of voltage divider: 130
- – Third terminal of voltage divider: 40
- – Fourth terminal of voltage divider: 6
- – Bottom terminal of voltage divider: 17
- – K terminal of first detector: 6
- – K terminal of first and second I.F. (Max.): 45
- – K terminal of first and second I.F. (Min.): 3
- – K terminal of second detector: 6
- – P terminal of second detector: 165
- – P terminal of H.F. oscillator, first and second I.F., first detector, and I.F. oscillator: 250
- – G terminal of first detector, second detector, and first and second I.F.: 110
- – G terminal of H.F. oscillator: 100
Controls & Indicators
Refer to the PDF for details.
Installation / Setup
The source does not provide specific information on installation or setup highlights, including wiring, clearances, calibration, or prerequisites.
Operation
Refer to the PDF for details.
Troubleshooting & Error Codes
Refer to the PDF for details.
Safety & Warnings
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Download 2 Manual (PDF – 1.0 MB)
Hammarlund Comet Pro 2 Manual: Provides schematics for troubleshooting and calibrating the second edition model. File size: 1.0 MB.
- Brand: Hammarlund-comet-pro-second-edition-manual-schematics
- Model: 2
- Type: Manual
- File size: 1.0 MB
Overview
Brief overview of the product.
Specifications
- Key spec 1
- Key spec 2
Controls & Indicators
Control panel/button layout.
Installation / Setup
- Step 1…
- Step 2…
Operation
Basic usage, modes, cycles.
Troubleshooting & Error Codes
| Issue / Code | Fix |
|---|---|
| Example | How to fix… |
Safety & Warnings
- Important warning…
Downloads
Hammarlund Comet Pro Second Edition Manual & Schematics Overview
The Hammarlund Comet Pro Second Edition is a classic communications receiver designed for amateur radio enthusiasts and professionals alike. Known for its robust construction and reliable performance, this device offers precise tuning and excellent sensitivity across a wide frequency range. The included manual and schematics provide comprehensive guidance for setup, operation, and maintenance to ensure optimal functionality.
Main Features and Specifications
- Wide frequency coverage from 540 kHz to 30 MHz
- Multiple tuning ranges with fine and coarse controls
- High sensitivity and selectivity for clear signal reception
- Built-in noise limiter and automatic gain control (AGC)
- Detailed schematic diagrams for troubleshooting and repairs
- Durable metal chassis designed for long-term use
- Audio output suitable for headphones or external speakers
Basic Usage and Operation Tips
To operate the Hammarlund Comet Pro, begin by powering on the unit and allowing it to warm up for a few minutes. Use the coarse tuning dial to select the desired frequency band, then fine-tune with the smaller knob for precise reception. Adjust the volume and tone controls to optimize audio clarity. Engage the noise limiter to reduce background static during weak signal reception. Regularly consult the manual’s frequency charts to identify and lock onto specific signals.
Troubleshooting and Maintenance Notes
If reception quality deteriorates or the unit fails to power on, first verify all power connections and fuses. Consult the schematic diagrams to check key components such as tubes, capacitors, and resistors for faults. Clean the tuning capacitor and switches periodically to prevent oxidation and ensure smooth operation. Store the receiver in a dry, dust-free environment to avoid corrosion and electrical shorts.
Safety Reminder
Always disconnect the Hammarlund Comet Pro from power before performing any maintenance or repairs. Avoid exposing the device to moisture or extreme temperatures. Use caution when handling internal components, as some parts may retain electrical charge even after power is removed. Follow all safety guidelines outlined in the manual to prevent injury or damage.
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