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Repeater Circuits


Last Updated: November 21, 2017 05:46 AM
Circuits Designed by Dave Johnson, P.E. :

40khz TV-VCR Light Source Repeater - This circuit is designed to be placed directly in front of a standard TV or VCR remote.  The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful.  Using the device, the remote can operate a TV or VCR over three times the normal distance. . . Circuit by David A. Johnson P.E.-June, 2000

Infrared Remote Extender Circuit - This circuit is designed to be placed directly in front of a standard TV or VCR remote.  The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

Remote Extender Circuit - This circuit is designed to be placed directly in front of a standard TV or VCR remote.  The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful.  Using the device, the remote can operate a TV or VCR over three times the normal distance. . . Circuit by Dave Johnson P.E.-June, 2000

TV-VCR Light Source 40Khz Repeater - This circuit is designed to be placed directly in front of a standard TV or VCR remote.  The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-368-7747


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

40khz TV-VCR Light Source Repeater -  This circuit is designed to be placed directly in front of a standard TV or VCR remote.  The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful.  Using the device, the remote can operate a TV or VCR over three times the normal distance. . . Circuit by David A. Johnson P.E.-June, 2000

A Crystal Heater construction project -  OK, here is the circuit I used - See image below.   The original National Semiconductor circuit had a 30 K resistor in series with a 400 F cap., both in parallel with the 100 K resistor on the input of the 1st LM324 section.   I found that combo to actually destabilize the operation of the controller for this particular application, so I removed them & changed the 2 F cap in series with the 10 megohm resistor to 5 F. __ Designed by Bob Dengler NO6B

A Phone Line Busy Sensing -  if you need to share a phone line between your home and a repeater, here's how.   __ Designed by Monte Smith, WDDIR, from ACC Notes, April, 1986.

A Repeater Fan Controller using a 556 IC -  This is a follow-up to the above with a modification to a single 556 chip.   __ Designed by George Henry KA3HSW

A Simple Circuit Echolink interface -  Easily constructed with about $10 in parts from Radio Shack.  Should work with any radio.   __ Designed by Courtesy of Matt Krick K3MK

A Simple Circuit Repeater Fan Controller -  Unlike many repeater systems, our local club repeater has always been located within a members home, many times in a basement or in this case, my home office area.  The latter created a desire to lower the noise level generated by the repeater, specifically, the power amplifier cooling fans. __ Designed by Robert Shepard KA9FLX

A Tone Beep Keyer for Repeaters -  Obtain an Audible indication of Off-Frequency Operation.   __ Designed by Originally Art Gentry W6MEP. Reprinted from May 1974 QST.

A VHF/UHF/LINK repeater interface/controller -  This is a set of nearly identical schematics for circuitry used to provide cross-band inter-agency communications.  __ 

Add a door-chime repeater -  05/13/99 EDN Design Ideas:  Electromechanical door chimes can enhance your home, but they are vulnerable to costly repair problems.  A defective pushbutton switch or a careless visitor can maintain the chime in an energized state for a prolonged period, thereby damaging the chime.  The circuit in Figure 1 prevents damage to the chime and improves the chime's effectiveness by repeating the chime strike for as long as the pushbutton remains depressed.  The circuit controls both front and rear chimes.  The heart of the circuit is timer IC 2, which you configure as an astable multivibrator.  The timing components, R1, R2, R3, and C3, provide the required pulse widths.   __ Circuit Design by Dennis Eichenberg, Parma Heights, OH

An Audio-Noise-Based Voting -  As hand-held transceivers (H-Ts) become smaller, and low power, battery conserving operation becomes more popular, the disparity between the transmitting range of a typical 100 watt repeater compared to the repeater accessing range of a typical 1 watt or less H-T becomes more and more apparent.  How often have you found it difficult (or impossible) to access a repeater with a low power H-T even though you can hear the repeater at full quieting? This can happen even if the repeater is equipped with a high sensitivity, state-of-the-art receiver.   __ Designed by Mark Kolber  WB2WHC

ATV Repeater Controllers -  Specifications and designs are subject to change without notice.  Use on your own risk. __ Designed by Mijo Kovacevic, S51KQ

Basic Stamp 1 & 2 Repeater Controller construction projects -  Cheap controllers   __ Designed by Roger Cameron NYOX.

Build a Two Channel Signal to Noise Voter -  As hand-held transceivers (H-Ts) become smaller, and low power, battery conserving operation becomes more popular, the disparity between the transmitting range of a typical 100 watt repeater compared to the repeater accessing range of a typical 1 watt or less H-T becomes more and more apparent.  How often have you found it difficult (or impossible) to access a repeater with a low power H-T even though you can hear the repeater at full quieting? This can happen even if the repeater is equipped with a high sensitivity, state-of-the-art receiver.   __ Designed by Mark Kolber  WB2WHC

Build Youself a Service Monitor? -  For creating a COS signal on radios that don't have one.  This is a VOX circuit that uses a FET as the input amplifier to avoid loading down the source.   __ Designed by Tom Alldread VA7TA

CH-25 Crystal Heater Kit -  As above with professional circuit board   __ Designed by Kevin Custer  W3KKC

COR Carrier Delay timer / Hang Timer -  Did you ever want a simple controller to key a transmitter from a receiver's cos?    Well here is a simple circuit that does just that.  The input impedance is fairly high, about 1 Meg, and will interface to most any receiver.  VR 1 is a sensitivity control that is adjusted to trigger the circuit with just about any available positive going signal.  A setable hang time is adjusted with VR 2.   __ Designed by Kevin Custer  W3KKC

Crystal heater / temperature stablization (TXCO) -  OK, here is the circuit I used - See image below.   The original National Semiconductor circuit had a 30 K resistor in series with a 400 F cap., both in parallel with the 100 K resistor on the input of the 1st LM324 section.   I found that combo to actually destabilize the operation of the controller for this particular application, so I removed them & changed the 2 F cap in series with the 10 megohm resistor to 5 F. __ Designed by Bob Dengler NO6B

Fix Adds Door Chime Repeater -  05/13/99 EDN Design Ideas:  Electromechanical door chimes can enhance your home, but they are vulnerable to costly repair problems.  A defective pushbutton switch or a careless visitor can maintain the chime in an energized state for a prolonged period, thereby damaging the chime.  The circuit in Figure 1 prevents damage to the chime and improves the chime's effectiveness by repeating the chime strike for as long as the pushbutton remains depressed.  The circuit controls both front and rear chimes.  The heart of the circuit is timer IC 2, which you configure as an astable multivibrator.  The timing components, R1, R2, R3, and C3, provide the required pulse widths.   __ Circuit Design by Dennis Eichenberg, Parma Heights, OH

Generic CM108 based USB sound adapter conversion article -  For AllStar (Asterisk) VoiP - Local Copy __ Designed by Author unknown - likely Steve RoDgers - WA6ZFT

Infrared Remote Extender Circuit -  This circuit is designed to be placed directly in front of a standard TV or VCR remote.  The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

Other Repeater Controller Construction Projects -  The links below will allow you to build several working repeater controllers.  No warranty as to the quality or usefulness is expressed by Repeater Builder.__ 

Protects Phone Line from Lightning Strikes -  To build a circuit that will help protect your equipment from lightning strikes on the phone line.  This circuit was actually designed to reduce or eliminate a very local broadcast AM radio stations signal from bombarding my parents telephone line, however it also turned out to be a really good lightning protector.  __ Designed by Kevin Custer  W3KKC

PTT Delay Circuit -  The delay circuit is inserted between the controller and transmitter to provide a set-able time delay keeping the transmitter keyed when using "zero hang time" and linking to another machine. To use this circuit, the controller's repeater ptt must be configured "high true" (dip switch 2 on). __ Designed by Kevin Custer  W3KKC

Remote Extender Circuit -  This circuit is designed to be placed directly in front of a standard TV or VCR remote.  The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful.  Using the device, the remote can operate a TV or VCR over three times the normal distance. . . Circuit by Dave Johnson P.E.-June, 2000

Repeater Fan Controller -  an 18 kB PDF file __ Designed by Robert Shepard KA9FLX

Simple Circuit fix adds door-chime repeater -  05/13/99 EDN Design Ideas:  Electromechanical door chimes can enhance your home, but they are vulnerable to costly repair problems.  A defective pushbutton switch or a careless visitor can maintain the chime in an energized state for a prolonged period, thereby damaging the chime.  The circuit in Figure 1 prevents damage to the chime and improves the chime's effectiveness by repeating the chime strike for as long as the pushbutton remains depressed.  The circuit controls both front and rear chimes.  The heart of the circuit is timer IC 2, which you configure as an astable multivibrator.  The timing components, R1, R2, R3, and C3, provide the required pulse widths.   __ Circuit Design by Dennis Eichenberg, Parma Heights, OH

Simple Circuit Repeater Fan Controller -  an 18 kB PDF file __ Designed by Robert Shepard KA9FLX

Smart VOX from Jet Propulsion Laboratory-Nasa -  For creating a COS signal from a radio that doesn't have one.  This circuit was developed to control the retransmission of NASA Select audio over JPL's W6ViO repeaters.   __ Designed by Randy Hammock KC6HUR and Jan Tarsala WB6VRN 

StarTech CM108 based USB sound adapter conversion article -  For AllStar (Asterisk) VoiP __ Designed by Kevin Custer  W3KKC

Telephone Line Filter / Protector -  To build a circuit that will help protect your equipment from lightning strikes on the phone line.  This circuit was actually designed to reduce or eliminate a very local broadcast AM radio stations signal from bombarding my parents telephone line, however it also turned out to be a really good lightning protector.  __ Designed by Kevin Custer  W3KKC

The Jet Propulsion Laboratory-"Smart VOX" -  For creating a COS signal from a radio that doesn't have one.  This circuit was developed to control the retransmission of NASA Select audio over JPL's W6ViO repeaters.   __ Designed by Randy Hammock KC6HUR and Jan Tarsala WB6VRN 

The Repeater Builder's Friend -  A device to help to you fix your repeater or program your controller __ Designed by Matt Krick K3MK

TV-VCR Light Source 40Khz Repeater -  This circuit is designed to be placed directly in front of a standard TV or VCR remote.  The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000


Repeater Circuits


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