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100 MHz modulated RF source for FM Band - I
needed a frequency reference for tuning up the RS-232 to 100 MHz RF desktop channel
adapter elsewhere on this site, when I found this Saronix crystal oscillator in my
junk box. A few minutes with VRStudio produced an ATtiny12 to make a tone, even
fewer...(schematic / circuit added 6/07) |
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10W HF Linear Amplifier - (circuit design
added 8/03) |
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14MHz SSB 10mW Transceiver - (electronic
circuit added 05/06/07) |
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175kHz Inductive Pulse Transmitter - This
circuit is discussed in more detain in the Experimenters Journal. The transmitter’s
six inch diameter coil launches powerful magnetic 175KHz ring pulses that can be
detected by the circuit below. ….(designed by David A. Johnson) |
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1W Portable PLL transmitter - This small FM
transmitter includes a limiter, a microphone amplifier and a PLL digital tuning. All
the parts are placed on one circuit board. The RF power is….(electronic circuit added
08/07/06) |
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2 channel RF remote control - This RF remote
control it runs at 418MHz frequency and support up to 2 channels. It is very safety as
the transmiting code is changing every time you push any button (roll-code
function)….(electronic schematic added 03/09) |
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2 Meter Transmitter - This project is a
simple transmitter using only one crystal and will cover 145.00 to 146.00 MHz. The
crystal is a 44.9333 MHz crystal for 145.500 receive, as used in the Trio (Kenwood)
2200, PYE, Motorola, Tait equipment, to name but four. The frequency of the crystal is
not critical as almost any other Xtal for the 2-meter band will function (added 8/03) |
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2 Valve 40m CW Transmitter - (electronic
design / schematic added 2/05) |
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2 Valve CW Transmitter - (electronic circuit
added 7/03) |
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222 MHz Transverter - (circuit design added
8/03) |
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2m-20m Transverter - This little circuit is a
transmitting and receiving converter (transverter) that converts a FT290 or similar
multimode handheld transciever to the 14MHz amateur band. The project is a single
board module that needs an external local oscillator, for example, the VHF harmonic
oscillator (or QRP VHF FM TX) LO for transverter project. It should be a relatively
simple matter of scaling coils(circuit / schematic design added 05/06/07) |
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2N2222 40 Meter CW/DSB Tranceiver - In spring
of 1998, NorCal sponsored a contest to design and build a project using no ICs and 22
or fewer 2N2222s as the active semiconductor devices. I thought this was a really
intriguing idea, so I set about to design my version.....(electronic schematic /
circuit added 4/02) |
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2-transistor FM Transmitter - While re are a
plethora of similar 2-transistor schematics available, this one is above average. A
major improvement over little 1-transistor circuit that we've discussed previously,
this transmitter consist of two stages. first transistor is used to amplify
audio,....(added 10/05) |
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3 Channel RF Remote Control - This is a 3
channel RF remote control project.The transmitter powered by 3V battery(coin size)
range about 10 m. This remote control I use PIC12F509 from Microchip which is a 8-pin
single-chip microcontroller designed for low pin count applications with 1 K words
flash memory and 41Byte SRAM and some special features such Power-saving Sleep
mode,Wake-up from Sleep on pin change. ….(electronic schematic added 11/08) |
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30 Meter QRP Transmitter for Morse Code -
This transmitters' intended purpose is for morse-code only in 30 meter band (Tony van
Roon's 10Mhz). It is a low-power QRP type and needs to be connected to your existing
tranceiver. harmonic rejections on prototype were measured at 40dB on 20Mhz and 50dB
on 30Mhz... added 4/02) |
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3W HF QRP Linear Amplifier - (circuit design
added 8/03) |
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4 Channel RF AVR Remote Control - How many
times you needed some remote control to handle some electric device ? many times.
There are lot of remote controls like infrared, RF, SMS (like my other circuit) and
more. The basic small-range remote controls are 2, Infrared and RF (Radio Frequency).
One of the weaks of Infrared is that the signal can not pass the walls. So, if you
want to control your garage door, the only way is to use some RF remote control. The
circuit (transmitter and receiver) use few components and ordinary (I love few
component circuits) . Its easy to build it because you don't have to tune-up any coil
or variable capacitor. The RF modules are fix to work in 418MHz area. ….(electronic
schematic added 11/08) |
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4 MHz Amplitude Modulated RF Source - A while
back I needed an amplitude modulated signal source at 4 MHz. This circuit was
literally thrown together with parts laying on the bench. I built it dead bug style on
a piece of copper clad board. It should work with little or no modification, other
thano get it to oscillate, and at higher frequencies, you might have to reduce the
capacitor values a little. Just be...(schematic / circuit added 6/07) |
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4 Transistor FM Transmitters (Andy Collinson)
- have used a pair of BC548 transistors in this circuit. Although not strictly RF
transistors, they still give good results. I have used an ECM Mic insert from Maplin
Electronics, order code FS43W. It is a two terminal ECM, but ordinary dynamic mic
inserts can also be used, simply omit the front 10k resistor....(circuit design added
8/03) |
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4 Transistor Transmitter - (circuit design
added 8/03) |
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49MHz Walkie Talkie - Lots of people are
requesting walkie-talkie and RF remote control schematics, so here is some. Building
se circuits needs special equipment and expertise in RF circuits. If you are going to
experiment with se circuits, please note that I did not build....added 8/03) |
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4W FM Transmitter - Don't be fooled by
relative simplicity of this transmitter. With 4W of power, it's not a toy! Since it
operates in FM band (88-108MHz), a license is required for broadcasting. With a good
and properly mounted antenna this baby has a range of up to 50km. In mountainous
terrain or in built-up areas, this figure is smaller, of course. circuit is fairly
small.…. (added 11/05) |
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5 Watt 80 Meter QRP CW Transceiver - A great
deal of interest has been generated by my previous design articles, so I decided to go
to work on a full blown transceiver design. After several months of work, the ROSE-80
transceiver was born. This transceiver is similar to other designs but contains some
unique differences. This design boasts the following features...)schematic added 8/03) |
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500mW HF Linear Amplifier - (circuit design
added 8/03) |
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60W Linear Amplifier - This is a RF Linear
amplifier for QRO using power mosfet IRF840 with power out 60 Watts. It's simple all
solid state circuit. The IRF series of power transistors….(circuit / schematic added
09/08) |
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8 Channel RF Remote Control - This is an 8
Channel RF Remote Transmitter and Receiver that will allow to remotely control various
electronic projects. RF Remote Control provides 2 latched and 6 momentary outputs that
could be used to control your favorite devices such as amplifier, robotic devices, RC
cars, computer, home appliances, lamps and many other cool gadgets. ….(electronic
schematic added 11/08) |
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80 Meter DSB Transmitter - (electronic design
/ schematic added 2/05) |
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807 & 1625 Valves - data on vacuum tubes 807)
and 1625 used in ham radio transmitters. Describes various pin voltages and different
operation modes. . (added 9/04) |
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A Basic RF Transmitter for PIR Sensors -
(circuit / schematic added 6/05) |
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Active FM Antenna Amplifier - This amplifier
will pull in al distanat FM stations clearly. The circuits is configured as a common-emmitter
tuned RF preamplifier wired around VHF/UHF transistor Q1….(Tony van Roon's schematic
added 10/06) |
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AM/FM/SW Active Antenna - This circuit shows
an active antenna that can be used for AM, FM, and shortwave SW. On shortwave band
this active antenna is comparable to a20 to30 foot wire antenna. This circuit uses
receivers that use untuned wire antennas, such as inexpensive units and car
radios....(added 4/02) |
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Analysis of NMR/MRI Coils using PIN Diode Switches
- (circuit added 6/07) |
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Assorted RF circuits - (circuit / schematic
added 6/05) |
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ATV Repeater Controllers - (electronic
schematic / circuit added 4/02) |
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Automatic message sender for CB - (circuit
added 6/07) |
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Automatic Repeater - This circuit will be of
interest to radio amateur and anyone possessing two radios, (one of which must be
able to transmit i.e. a transceiver). It is a self powered (audio derived) repeater
circuit for receiving a signal and re-transmitting it via or radio. (added 10/05) |
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Basic RF Oscillator #1 - This basic circuit
is eash to build and the components are not critical. Most of them can be found in
your junk parts box….(Tony van Roon's electronic schematic / circuit added 4/02) |
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Building a Simple LF Exciter - (circuit
design added 8/03) |
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Building an RF Remote Control System -
(electronic circuit added 04/05) |
