ATV repeater controllers
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Repeater beeper
The signal from COR triggers U1, which produces a beep-gate pulse that enables the analog gate. This gate consists of D2 and D3 to pass the beep tone generated by U2.
The circuit operates by utilizing a signal from the COR...
RF field strength meter
A simple Field Strength Meter consists of a small antenna, a detector diode, a resistor, a capacitor, and a micro ammeter. This circuit is sensitive enough to detect HF fields when positioned close to the transmitting antenna. The circuit functioned...
4 Band Double Tuned Preselector
The circuit requires an RF input, which can be sourced from either a long wire or a loop antenna. The preamplifier operates within a frequency range from 550 kHz (Medium Wave) up to 30 MHz in the shortwave band. The...
Sensitive RF Voltmeter Probe
Sensitive RF Voltmeter Probe Circuit. This circuit measures RF voltages beyond 200 MHz and up to about 5 V. PARTS LIST: R1 - 4.7 MΩ, R2 - 1 MΩ, R3 - 1 MΩ, R4 - 100 kΩ, R5 - 330...
RF-powered sidetone oscillator
A sidetone oscillator is a specific type of audio astable multivibrator. Keying is achieved by turning the oscillator on and off through the application of a positive DC potential, which is generated from the RF signal to the reset terminal...
RF Inductance Meter
This RF inductance meter measures RF chokes in the 500 nH to 50 µH range. A simple solution was required to measure hand-wound RF inductors in a secondary lab setting. The user intended to utilize this device occasionally and did...
Rf-Type Battery Charger Circuit
This type of charger transfers RF energy from an inductor (L2) to an external pickup coil. The pickup coil is connected to a rectifier and a battery that requires charging. This design is advantageous as it eliminates the need for...
Radio Field Indicator Circuit
An RF field indicator is needed to verify power stages and transmitter antennas. This radio field indicator allows for the measurement of radiated energy from antennas.
An RF field indicator is a crucial device in the field of telecommunications and broadcasting....
ATV Repeater System Exciter
The ATV exciter described here uses a pair of Hamtronics model TA451 2-watt narrow-band FM voice transmitters to develop video and audio carriers on 439.250 MHz and 443.750 MHz. The TA451 is a single board, phase modulated exciter designed for...