The ATL-3 Loop Antenna
All ATL-3 loop windings are centre tapped and balanced w. r. t. their amplifier/receiver chassis ground, and therefore electric field interference pick up tends...
AM Receiver
This is a compact three transistor, regenerative receiver with fixed feedback. It is similar in principle to the ZN414 radio IC which is now replaced by the MK4...
ZN414 portable Receiver
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6 x 6 Loop Antenna
This new loop antenna by Graham Maynard is his best design yet and I am proud to be the first to present his work. It uses one, six foot square, six turn loop, ...
2 Transistor Transmitter
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2 Transistor FM Voice Transmitter
Although only low power this circuit may be tuned to operate over the range 87-108MHz with a range of 20 or 30 metres. I have used a pair of BC548 transistors i...
1.5 Volt Tracking Transmitter
1.5 Volt Tracking Transmitter, Simple circuits , The current draw for this tracker is 3.7mA, so the 1.5V button cell will last awhile. What the heck am I suppos...
HF VHF receiver diplexer
An Icom PCR-1000 listening to various MF, HF and VHF radio stations. However, there is a slight problem. Very slight, almost too small to even mention, more of ...
The General Electric XT-1-A AM transmitter
Back in the day when AM was king, no expense was spared on transmitting equipment. I remember the GE BTA-25 transmitter from the same era, it was build like a t...
Methods for generating Amplitude Modulation
Amplitude Modulation (AKA AM) was the first modulation type to impress audio on an RF carrier. Prior to this, information was transmitted via on/off keying of a...
The K9AY receiving loop antenna
I decided to make my own K9AY antenna system and controller. Basically, after looking at the currently available commercial version, I figured I could make a be...
Dont Kill Dipole
Try this on for size. This is Tesla`s own words. From: ""On Light and Other High Frequency Phenomena"" ""ON PHENOMENA PRODUCED BY.....
Ultra wideband RF detector design challenge
I`d like to make a wideband RF detector. I`m thinking of using a range of resonant LC tanks, 5 to 10 mhz apart, (except / or 1 mhz apart from 9 to.....
Donald Smith Devices too good to be true 14
Originally Posted by kajunkreations The natural resonant freq of the L2 is 31.5 mhz. I calculated the 40K by using LC meter and LC resonance.....
Brovin Kacher Tesla
The "cold electricity" is actually RF frequency AC. When you have sinusoidal AC the voltage is half the time positive and half the time negative. On a scope you...
Simple IF Signal Generator
A versatile circuit of IF signal generator which may be of interest to radio hobbyists and professionals alike. Transistors T1 and T2 form an astable multivibra...
Bipolar Regenerative receiver
Contrary to what some radio experimenters think, a bipolar regenerative design can be made to work efficiently. The major concern is the low input impedance of ...
FM voice transmitter for Band 2 VHF
This small transmitter uses a hartley type oscillator. Normally the capacitor in the tank circuit would connect at the base of the transistor, but at VHF the ba...
MK414 SW Receiver
The original data sheet for the MK414 states a maximum working frequency is around 4 MHz. SW transmissions are so powerful that this receiver will work well wit...
MK484 Portable Receiver
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