Hammarlund-bc-799-air-force MODIFICATION – Manual (PDF)

The manual provides instructions for modifying the Radio Receiver BC-779 to include a quick-disconnect antenna feature by replacing screw-type terminals with a coaxial connector, detailing steps such as removing side plates and drilling mounting holes. It specifies that the modification should be performed during depot-level maintenance and requires approximately two man-hours to complete.

• Brand: Hammarlund
• Model: MODIFICATION
• Type: manual
• File size: 97.9 KB

Manual Overview

The manual details the modification of the Radio Receiver BC-779 to include a quick-disconnect antenna feature, replacing screw-type terminals with a coaxial connector SO-239. This modification is to be performed during depot-level maintenance. The process involves removing the existing antenna terminal strip and unsoldering the attached wire. The SO-239 connector is then mounted by drilling four holes in the back plate, using the connector as a template. The wire previously unsoldered is soldered to the new connector, which is secured with machine screws and brass nuts. The removed side plates are then replaced. The modification requires specific parts, including the SO-239 connector, machine screws, and brass nuts, all of which should be requisitioned from the Rome Air Force Depot. Approximately two man-hours are needed to complete the modification. No special tools are required for the installation. Removed parts, such as the antenna terminal strip, are to be condemned and tagged for disposal.

Quick Issues Covered

• Quick-disconnect antenna modification for BC-779 receiver.
• Instructions for replacing antenna terminals with SO-239 connector.
• Modification requires depot level maintenance and specific parts.

Overview

This document is a technical order from the United States Air Force detailing the modification of the Radio Receiver BC-779 to include a quick-disconnect antenna feature. The modification involves replacing screw-type terminals with a coaxial connector, SO-239, to allow for rapid connection and disconnection of the antenna. The work is to be accomplished during Depot Level Maintenance, and specific parts and procedures are outlined for the modification process.

Specifications

• Radio Receiver BC-779
• Connector: SO-239
• Machine Screw: RH 4-48 x 3-in
• Nut: 4-48, plain, brass
• Man-hours required: Approximately two

Controls & Indicators

Refer to the PDF for details.

Installation / Setup

The setup involves replacing the screw-type antenna terminals on the Radio Receiver BC-779 with a coaxial connector SO-239 for quick-disconnect capability. The process includes removing side plates and the antenna terminal strip, reaming and drilling holes for the new connector, soldering wires, and fastening the connector with screws and nuts. No special tools are required, and the modification takes approximately two man-hours.

Operation

Refer to the PDF for details.

Troubleshooting & Error Codes

Refer to the PDF for details.

Safety & Warnings

Refer to the PDF for details.

Download MODIFICATION Manual (PDF – 97.9 KB)

Hammarlund BC-799 Air Force MODIFICATION manual: Guide for implementing technical modifications. File size: 97.9 KB.

• Brand: Hammarlund-bc-799-air-force
• Model: MODIFICATION
• Type: Manual
• File size: 97.9 KB

Overview

Brief overview of the product.

Specifications

• Key spec 1
• Key spec 2

Controls & Indicators

Control panel/button layout.

Installation / Setup

1. Step 1…
2. Step 2…

Operation

Basic usage, modes, cycles.

Troubleshooting & Error Codes

Safety & Warnings

• Important warning…

Downloads

Download MODIFICATION manual (PDF)

Hammarlund-bc-799-air-force MODIFICATION – Overview

The Hammarlund-bc-799-air-force is a vintage military communications receiver designed for reliable shortwave and HF signal reception. Originally developed for Air Force use, this model offers robust performance in demanding environments, making it ideal for monitoring a wide range of frequencies with precision and clarity. The MODIFICATION manual provides detailed instructions on enhancing and maintaining the BC-799 to ensure optimal operation.

Main Features and Specifications

• Frequency coverage: 1.5 MHz to 18 MHz
• Superheterodyne receiver design for improved selectivity and sensitivity
• Multiple tuning ranges with fine calibration
• Built-in audio amplifier and headphone jack
• Durable metal chassis suitable for field use
• Power supply options: AC mains or external DC source
• Modification instructions for enhanced frequency stability and signal clarity

Basic Usage and Operation Tips

To operate the Hammarlund-bc-799-air-force, first ensure the device is properly powered and connected to an appropriate antenna. Begin by selecting the desired frequency range using the tuning dial, then fine-tune the signal for the clearest reception. Use the volume control to adjust audio output to a comfortable level. Regularly calibrate the dial using the built-in calibration markers to maintain frequency accuracy. For best results, operate the receiver in a location free from electrical interference.

Troubleshooting and Maintenance

If you experience weak or distorted signals, check antenna connections and verify power supply stability. Inspect tubes and replace any that show signs of wear or damage. Clean all contacts and switches periodically to prevent oxidation and ensure smooth operation. Refer to the modification manual for detailed circuit adjustments to improve performance. Always discharge capacitors before servicing to avoid electrical shock.

Safety Reminder

When servicing or modifying the Hammarlund-bc-799-air-force, always disconnect power sources to prevent electric shock. Use insulated tools and follow proper grounding procedures. Handle vacuum tubes carefully as they can become hot during operation and are fragile. Keep the device away from moisture and extreme temperatures to avoid damage and ensure safe operation.