There are 214 circuit schematics available. Last circuit added on Saturday, 30 May 2015.

CircuitCategoryDate AddedOK?
4 channel 433MHz remote control transmitter / receiver based on SM5162 and SM5172 chipsRF 
SCA Adapter - listen to advertisement free background music on FM broadcast radioRFSep 23, 2009
Experimental DSB/CW QRP rig for 20 and 40 meter bands (PDF)RFOct 05, 2009
Simple 40 meters CW QRP Transceiver (PDF)RFOct 05, 2009
20 meters CW QRP Transceiver (PDF)RFOct 05, 2009
USB 0-500MHz RF Power Meter based on a AD8307RFFeb 21, 2013
Simple FM receiver based on a TEA5591 ICRFMar 23, 2015
Electronic Eavesdropping Devices DetectorRFJun 26, 2009
Radio Wave AlarmRFJun 26, 2009
Linear FM 50Watt with BLY90RFJun 28, 2009
UHF Preamplifier covers 450MHz - 800MHz based on MPSH10 / BF180 / BCY90RFJun 28, 2009
60W Linear amplifier using IRF840 power MOSFETRFJun 28, 2009
Send Morse on your VHF RigRF 
An end-fed antenna, L-match coupler and resistive bridge for HFRF 
Regenerative receiver for the AM broadcast band using two transistorsRF 
Novel crystal set requires no antenna, earthRF 
80 meter direct conversion receiverRF 
A compact L-match ATU for portable useRF 
Converter to yune six metres on your two metre receiverRF 
High quality AM through your FM stereoRF 
Converter to Hear Amateurs on your FM RadioRF 
RF Actuated Keying MonitorRF 
LF to HF ConverterRF 
Super 80 ultra-simple SSB receiver for 3.5 MHz a basic superhetRF 
Basic 10GHz / 24GHz gunplexer / gunn diode control circuit (PDF)RF 
50 MHz to 10 MHz receive converterRFJun 19, 2011
17M to 6M transveter circuit diagramRFJun 19, 2011
metre receiverRFJun 19, 2011
Passive grid (tube based) linear amplifierRFJun 19, 2011
T-Match ATU (antenna tuning unit)RFJun 19, 2011
Single transistor receiver for SSB, CW, AM using a VHF dual gate MOSFETRFJun 19, 2011
Multi band SSB transceiver construction projectRFJun 19, 2011
Receiver building blocksRFSep 06, 2001
Digital display and VFO stabiliser using a PIC microcontroller and LCDRFJun 19, 2011
SSB transceiver for 80MRFJun 19, 2011
VHF receiver convertererRF 
Circuit diagrams for 418/433 MHz short-range communication (Elektor Electronics article)RFApr 12, 2014
Circuit diagram for superregenerative receiver built by GE labsRFApr 12, 2014
X10 RF daughter board - receiver circuit diagramRFApr 12, 2014
RX3302 433MHz superregenerative receiver module circuit diagramRFApr 12, 2014
Automicro RX3304 receiver module schematicRFApr 12, 2014
49MHz walkie-talkie circuit diagram that uses only three transistorsRFApr 12, 2014
Superregenerative 27MHz receiverRFMar 23, 2003
Montreal Doppler 3 DF (direction finder) unitRFApr 14, 2011
Construction details for 30 meter rig with superhet receiver and crystal controlled transmitterRFApr 12, 2014
All Discrete Components 40 M transceiver with super-het receiver using no IC'sRFApr 12, 2014
Versatile L tuner for end feed wire antennas that fits in an Altoids tin.RFApr 12, 2014
MMR-40 40 meter rig with SSB (voice) and CW (Morse code) operating modes.RFApr 12, 2014
An 80 meter rig for the MAS contest by KD1JVRFApr 12, 2014
A unique PSK transceiver, Version 2 By Steven Weber, KD1JVRFApr 12, 2014
(Fairly) Simple 75M SSB rig with PTTRFApr 12, 2014
AM Short Wave Broadcast Receiver circuit diagramRF 
Universal USB digimode interface supports CAT (Yaesu), CI/V (Icom) and RS-232 (Kenwood) units (PDF)RFOct 07, 2009
Convert 2m VHF FM PMR transceiver Motorola Radius M110 into an amateur radioRFJun 18, 2003
Simple CW identifier for a FM repeater (PDF)RFOct 07, 2009
6m SSB & CW QRP transceiverRFOct 07, 2009
80m SSB & CW QRP superhet transceiverRFOct 07, 2009
Pocket sized 20m (30m) CW QRP transceiverRFOct 07, 2009
USB / CAT (CI-V) adapter tested with FT-8900, FTB-9800, VX-7R, VX-7, FT-817 and IC-706MkIIGRFOct 07, 2009
Wideband SWR meterRF 
SCA Subcarrier Demodulator for FM broadcast stationsRF 
118MHz to 136MHz aircraft receiver circuit diagramRFJul 03, 2011
1300MHz - 1500MHz antenna with amplifier based on two MAR-8 RF amplifiersRFJul 03, 2011
Shortwave received circuit diagramRFJul 03, 2011
Beat frequency oscillator for AM/SW radio receiversRFMay 25, 2012
Direct conversion 7MHz receiver using NE602RFMay 25, 2012
WWV receiverRFMay 25, 2012
1.5 GHz PLL Frequency SynthesizerRFApr 10, 2014
Transverter for Converting SSB CB to LF for Thru-the-Earth Voice CommunicationsRFMar 03, 2011
Simple ADS-B aircraft transponder decoder based on a PIC18F2550 microcontrollerRFDec 09, 2010
Active RF antennuatorRFApr 14, 2011
Simple Time-Difference-Of-Arrival RDFRFApr 14, 2011
555 Time-Difference-Of-Arrival RDFRFApr 14, 2011
50MHz converter project based on a NE602/SA602/NE612RF 
HF/6M Antenna Tuner Preselector and Antenna SwitcherRF 
Direct Crystal radio receiver examplesRF 
MW Enhanced Crystal Receiver using 741 ICRF 
455 Khz MF to AF converter used for DRM reception in a Yaesu FRG-100 receiverRF 
Sensitive LW/MW/SW Shortwave general coverage receiverRF 
10 meter (28MHz) band RF amplifierRF 
MW/SW Radio receiverRF 
Bipolar transistor RF mixerRF 
HF/VHF mini portable antenna tunerRF 
Wideband VHF/UHF/SHF 22dB RF preamp with MAR-6 or MAR-8 (MSA-0885)RF 
HF 10 watt amplifier for 18MHz using a 2SC1969/2SC1944 transistorRF 
RF Power meter / dummy loadRF 
SWR bridge covering HF to VHFRF 
VHF 6 Meterband RF amplifierRF 
HF/VHF portable antenna tunerRF 
Aircraft Radio Communications ReceiverRFSep 01, 2009
Crystal RadioRFSep 01, 2009
Op Amp RadioRFSep 01, 2009
Class B series modulatorRF 
Build a Crystal Set (simple AM radio receiver)RFApr 10, 2014
Precision Frequency Control for AM Radios - A Frequency Synthesized Local OscillatorRFApr 10, 2014
DSP-RDF Doppler Radio Direction Finder circuit schematic - complete kit availableRFApr 14, 2011
50O Load and Power MeterRFFeb 21, 2013
External antenna for the GPS-38, Magellan 2000, or Eagle Explorer GPS receiversRFMay 01, 2004
175KHz inductive pulse receiver (PDF)RFJan 26, 2001
200-400 MHz voltage controlled oscillator (PDF)RFJan 26, 2001
AM/FM/SW active antennaRFJan 26, 2001
RF Sniffer under 0.5MHz to above 500MHzRFJan 26, 2001
Electronic Eavesdropping Devices Detector (bug detector)RFFeb 21, 2005
20dB VHF AmplifierRFFeb 21, 2005
30 watt FM linear amplifier circuit diagramRFFeb 21, 2005
Linear FM 50 watt amplifier with BLY90RFFeb 21, 2005
CB (27MHz citizens band) receiverRFFeb 21, 2005
AM BCB radio receiverRFOct 23, 2002
Regenerative shortwave receiverRFJun 08, 2002
RF front-end for triple conversion GPS receiver (PDF)RFMar 01, 2003
7MHz SSB TransceiverRFMay 01, 2004
AM receiver circuit diagramRFSep 08, 2009
inexpensive high speed microwave data link using an Alpha Gunnplexer for 10 Mbps data rateRF 
18 dB LT1253 DDS amplifier circuit diagramRF 
23 dB Bipolar DDS AmplifierRF 
15M CW Transceiver designRF 
20 Meter CW TransceiverRF 
30 Meter, Discrete Component CW Transceiver Built Manhattan-styleRF 
K8IQY's Original 2N2/40 CW Transceiver RigRF 
40 to 6 Meter "No Tune" TransverterRF 
SW30+ 30 Meter CW TransceiverRF 
Wave Bubble self-tuning portable RF jammerRF 
Wave Bubble - A design for a self-tuning portable RF jammerRFOct 12, 2009
Simple home made ADS-B receiver that takes IF from a modified receiverRFOct 04, 2010
Very Simple ADSB Receiver using a TV tunder to allow reception of aircraft transpondersRFOct 04, 2010
115200 RS232 QPSK RF modem projectRFOct 04, 2010
Yaesu FT-736R doppler compensationRFAug 14, 2002
30M PSK31 Transceiver circuit diagramRFFeb 25, 2003
SOP receiver (PDF)RFOct 30, 2002
SOP direct conversion receiverRFJan 06, 2002
Electroluminescent Receiver Kit includes circuit diagramRF 
Receiver based on NE602RFJan 26, 2001
DC40 - 40M Direct Conversion receiverRFOct 08, 2009
SSB linear amplifier made from a bunch of 2N2218 transistorsRFOct 08, 2009
Simple Dual Band SSB Transceiver (20/40 meters)RFOct 08, 2009
30M Direct Conversion Receiver ProjectRF 
Active Antenna ExperimentsRF 
Cascode 7 Experimental ReceiverRF 
75 Meter QRP SSB TransceiverRF 
Junk Box NDB Low Pass FilterRF 
Popcorn Direct Conversion Main FrameRF 
40 Meter Popcorn Superhet ReceiverRF 
RF preamp circuit diagramsRF 
Some experiments with active or voltage probe antennas (VPA)RF 
MF and HF Receive Antenna SplitterRF 
Medium Frequency TRF ReceiverRF 
40 Meter Band Direct Conversion experimental receiverRF 
Wee Willy 75 Meter DSB Transceiver ProjectRF 
10 MHz WWV Receiver circuit diagramRF 
Cascode Hybrid-Based WWV Receiver for 5 MHzRF 
40m band direct conversion receiverRFJan 06, 2002
80m band direct conversion receiverRFJan 06, 2002
Regenerative Short Wave RadioRF 
Homebrew 20m CW TransceiverRF 
Homebrew 30m CW TransceiverRF 
Homebrew 40m CW TransceiverRF 
Homebrew 6m SSB/CW TransceiverRF 
Homebrew 6m DSB TransceiverRF 
FPGA Based ADS-B Receiver and DecoderRFDec 09, 2010
136 kHz direct conversion receiverRFJan 06, 2002
Audible S-MeterRF 
40 Segment LED S-Meter circuit diagramRF 
Bi-Directional 2.4 GHz One Watt AmplifierRFJun 13, 2002
Bi-Directional 900Mhz One Watt AmplifierRFJun 13, 2002
20 Watt GaAaFET Power on 2.3 GHzRFJun 13, 2002
1 Watt 2.3 GHz RF Amplifier Using a MRF2001RFJun 13, 2002
One Watt 2.45 GHz Linear Amplifier using RF Micro Devices RF2126RFOct 31, 2002
2.3 GHz Power AmplifiersRFJun 13, 2002
2304 and 3456 MHz Power AmplifiersRFJun 13, 2002
High Frequency VCO Design and SchematicsRFOct 25, 2014
Dopler RDF (radio direction finder) circuitRF 
VFO from 2001 ARRL Handbook, page 17.74RFNov 01, 2002
VFO from 2001 ARRL Handbook, page 14.20RFNov 01, 2002
Assorted RF circuitsRFMar 18, 2003
14MHz SSB 10mW TransceiverRFFeb 24, 2003
VLF radio receiver schematicRFApr 17, 2004
VLF Upconverter for Shortwave ReceiverRFSep 13, 2006
Basic Vox CircuitRF 
Variable Bandwidth CW FilterRF 
An Inexpensive Tone EncoderRF 
5 watt, 80 meter QRP CW TransceiverRFJun 08, 2002
Build a good GaAs FET preamp for 2 meters, 222MHz or 440MHzRF 
Two Transistor Reflex RadioRFAug 17, 2009
R2T2 Haywire Home StationRFOct 07, 2009
ICOM CI-V interface with RS232 RTS to PTTRFMay 01, 2004
Active Antenna AA-7 HF/VHF/UHF, 3-3000MHzRF 
Active antenna 1 to 20dB, 1-30 MHz rangeRF 
Active Antenna for AM-FM-SWRF 
FM radio active antennaRF 
Aviation band receiverRF 
Broadcast-Band RF AmplifierRF 
Bug detector with beep using 7413 or 74LS13RFJan 26, 2001
Bug detector / countersurveillance monitorRF 
Basic RF oscillatorRFJan 26, 2001
Subcarrier adapter to listen to hidden subcarrier signals on FM radioRF 
Galvanic isolated CAT & audio interface for amateur radioRF 
Morse Code Beacon KeyerRFSep 21, 2006
Improved FM Stereo ModulatorRFJul 09, 2002
The House Finch Direct Conversion Tube ReceiverRFMay 19, 2015
WB0RIO Piglet 6U8A Regenerative Receiver (Tube based)RFMay 19, 2015
QRP Antenna TunerRFSep 21, 2006
Smooth Tone Clickless CW Sidetone GeneratorRFSep 21, 2006
High Fidelity FM Stereo Modulator (Rev E2)RFMay 19, 2015
Variety of receiver converter projectsRFApr 24, 2001
One transistor FM receiverRFApr 24, 2001
42 Mc Band to 88 Mc Band (retrofit converter) ProjectRFApr 24, 2001
RF noise bridge for HFRF 
160m mini portable End Fed Half Wave Tuner - MkIIRF 
Crystal radio circuits including diode performance comparisonRFMar 10, 2003
Simple RIT circuit based on a 2N7000 FETRFSep 01, 2009
56K RF Modem circuit diagramRFJan 06, 2002
5 tubes SSB QRP Transceiver for 20m Ham bandRF 
2m (144MHz) Dual Gate FET Low Noise AmplifierRF 
Kenwood TR-7950 manual & schematics (PDF)RFSep 10, 2006