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The Old CATV Equipment Museum
The Early Years: Before CATV

Distribution Amplifiers

CONTENTS OF THIS PAGE
Foreword by Neal McLain
Jerrold Model ADO-2 Antenna Distribution Outlet
Jerrold Model AOC-26-B "Cascader" Distribution Amplifier
Jerrold Model 2300 Broadband Amplifier with 300-ohm output terminals
Jerrold Model 2300 Broadband Amplifier with 75-ohm output connector
Input strapping chart for Jerrold 2300 series amplifiers
Jerrold Model UBC-26B "Golden Cascader" Distribution Amplifier
Pole-mounted weather-resistant amplifier cabinet

Foreword
by Neal McLain

The term "distribution amplifier" covers a lot of territory.   Generally speaking, these amplifiers:

  • Utilized vacuum-tube technology.
  • Were designed for indoor installation.
  • Required 115-volt 60-Hz operating power.
  • Were constructed on steel or aluminum chassis.
  • Were fitted with some sort of metal cover to provide mechanical (but not weather or dust) protection.

The earliest distribution amplifiers were designed for home use.   They were fitted with 300-ohm input and output connectors for use with 300-ohm dipole antennas and twinlead interior wiring.

Later versions were fitted with coaxial connectors for use with coaxial interior wiring in homes and MDUs.   As the MDU market grew, manufacturers developed specialized distribution amplifiers with higher output power levels to feed multiple outlets.   They could be connected to receive signals from a rooftop antenna, a cable TV drop, or master antenna system.

As the cable television industry grew, some cable operators began using distribution amplifiers as line amplifiers, often installed in pole-mounted weather-resistant cabinets.   One such installation was featured on the cover of the March 1964 issue of TV & Communications magazine.


Jerrold Model ADO-2 Antenna Distribution Outlet

Photo:Lew ChandlerHigh resolution

Photo:Lew Chandler

 
Photo:Lew Chandler

Jerrold Model AOC-26-B
"Cascader" Distribution Amplifier

Photo:Lew ChandlerHigh resolution

 
Photo:Lew Chandler

Photo:Lew Chandler

Jerrold Model 2300 Broadband Amplifier
with 300-ohm output terminals

Photo:Lew Chandler

Photo:Lew Chandler

Photo:Lew Chandler

Photo:Lew ChandlerHigh resolution

Jerrold Model 2300 Broadband Amplifier
with 75-ohm output connector

Photo:Lew Chandler

Photo:Lew Chandler

Photo:Lew Chandler

Photo:Lew ChandlerHigh resolution

Jerrold Model 2300 Broadband Amplifier
Input strapping chart

This chart applies to both Model 2300 Amplifiers shown above.
Option
Input
impedance
Terminal
Configuration
Matching
cable
Typical
application
All-band (Channels 2-13 + FM band) VHF signal 300 ohms Screw Twinlead All-band antenna
75 ohms C-connector Coaxial All-band signal from CATV, MATV, or antenna.
Separate low band (Channels 2-6) and high-band (Channels 7-13) signals 300 ohms Screw Twinlead Separate low band and high-band antennas
75 ohms C-connector Coaxial Separate low band and high-band antennas.


Jerrold Model UBC-26-B
"Golden Cascader" Distribution Amplifier

Photo:Lew ChandlerHigh resolution

 
Photos:Lew Chandler

Photo:Lew Chandler

Pole-mounted weather-resistant amplifier cabinet

Scan:Lew Chandler
Installation of a Davco Model EQ-2 equipment housing for a line amplifier.   Robert Harmon (left), of Davco, makes the connections to the cable network, while an unidentified lineman from Arkansas Power & Light Company makes the connection to the 120-volt secondary distribution conductors.   Photo: TV & Communications Magazine, March 1964, front cover.   We thank Robert Harmon's family for contributing this issue of the magazine to the Museum.

Scan:Lew ChandlerAdvertisement for Davco Model EQ-2 equipment enclosure.   Source: TV & Communications Magazine, March 1964.


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