Low-Power Antenna Tuner Circuit
This antenna tuner is suitable for use with low-power (less than 5 W) transmitters or SW receivers. S2 selects inductance and S2 connects the 365-pF capacitor ...
Automatic Tr Switch Circuit
A pair of diodes and a quarter-wave transmission line are used as an automatic TR switch. D1 and D2 conduct during transmit periods, short- circuiting the scan...
Hf Broadband Antenna Preamp Circuit
The HF/SW receiver preamplifier is comprised of a broadband toroidal transformer (LI-a and Ll-b), LC network (comprised of a 1600-kHz, high- pass filter-and a ...
Wideband Antenna Preamplifier Circuit
This wideband antenna preamplifier has a gain of around 20 dB from 40 to 860 MHz, covering the entire VHF, FM, commercial, and UHF bands....
Vlf/Vhf Wideband Low-Noise Active Antenna Circuit
A 30- to 50-cm whip antenna provides reception from 10 kHz to over 220 MHz. Tl, a dual-gate MOSFET, provides low noise, high-input impedance, and high gain,...
Dual-Band Loop Antenna For 80-160 M Circuit
This antenna might help to reduce power-line noise. A plastic hula hoop or conduit 3 feet in diameter, covered with aluminum foil as a shield is used for LI an...
Wireless Fm Microphone
A simple FM wireless microphone uses a single BC183C transistor as an audio amplifier. A 2N3565 can be substituted. ...
5W 80M Cw Transceiver
This transceiver has a 3-stage transmitter and a direct-conversion receiver. Ql is the transmitter"s oscillator, an...
Hf Low-Power Cw Transmitter
Suitable for amateur use, this 1.5-W transmitter runs on a 12-V supply. Ql is an oscillator using a surplus FT2...
2M Transmitter
The transmitter was designed specifically for use by radio amateurs as a radio beacon. As such, it provides a good-quality ...
Amateur Television Transmitter
Although the unit was designed for 2 W operation, Q6 and Q7 stages and associated components can be omitted ...
Inexpensive Vhf/Uhf Diode Rf Switch
This circuit uses low-cost IN4148 diodes and exhibits about 1.5 dB insertion loss from 10 to 1000 MHz w...
Diode Rf Switch
Dl and D2 can be IN914B- or HP2800-series diodes (for UHF). The loss is over 60 dB in the off state, and less than 3 dB at ...
Rf Upconverter For Tvro Subcarrier Reception
This converter uses a 40673 MOSFET to heterodyne the 5.5- to 8-MHz TVRO subcarriers to the FM ...
220Mhz Receiving Converter
A simple circuit using a single transistor converts 220 MHz to 144 MHz or vice versa, because the mixer is bila...
Shortwave Converter For Am Car Radios
Using a Signetics NE602, this converter tunes the 9.5- to 9.8-MHz range. An AM car radio is used as a...
Receiver Frequency-Converter Stage
In this case, the NE602 is used in this superhet front-end configuration. Ul serves as a frequency conve...
2Meter Converter
This converter enables a receiver that tunes 28 to 32 MHz to receive the 144- to 148-MHz amateur band. A BF981 dual-gate ...
Vlf Converter
The VLF Converter can be used to pick up signals for the general coverage of shortwave receivers. A number of unusual signals...
Low-Noise 420Mhz Atv Receiver/Converter
Ll, Ql, L2, and L3 compose an RF amplifier stage that feeds Ml, a doubly balanced mixer. Q4 is a l...