CW 250mW transmitter
Here is a simple little HF TX. It may be modified for all the HF bands, but the details given are only for the 7MHz band. The basic transmitter uses two transis...
High quality FM transmitter
This will probably be one of the last transmitters for the 88MHz to 108MHz band. This particular TX is of special interest to those wishing to build low power P...
AM IF filter
Typical QRP receivers include Direct Conversion (DC) and simple Superheterodyne types. These receivers often have quite a wide AF bandwidth which can make intel...
76MHz to 119MHz Fm transmitter
TR1 (BC547) is an inverted Hartley oscillator which based upon an inductor fabricated on the PCB. This makes it megga-stable, and setable anywhere in the VHF F...
2 Watt VHF linear amplifier
Once again my collection of projects creation has been interrupted by another necessity. Patrick and other people have asked me for a circuit of a VHF power amp...
27MHz CW transmitter
The original TX was designed to be only PULSE Modulated for a proportional R/C system, but I later used the same circuit to make an HF bands Amplitude Modulati...
wireless FM bug
This project is a miniature, VHF FM (wideband) Wireless Microphone transmitter of the type that are commonly refered to as BUG's. Note that "BUGS" are illegal b...
CW Transmitter 5 Watt
This is a very simple 5 watt CW TX based upon a TTL logic chip. There is just one "tricky" component and this is Cx. This component should have an impedance of ...
VHF preamplifier with BFY91
When the start switch is pushed, the output of the charger goes to 14.5 V. As the batttery approaches full charge, the charging current decreases and the outpu...
30 Meters CW transmitter
This transmitters' intended purpose is for morse-code only in the 30 meter band (10Mhz). It is a low-power QRP type and needs to be connected to your existing ...
VHF - UHF band reciever
Here is a nice little receiver for narrow-band FM reception. It can also be used to receive FSK, RTTY and PACKET signals from the HF bands. Basic receiver sensi...
FM reciever Tube reciever
This circuit is an FM 88-108 MHz reciever....
CW reciever with Tubes
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RF power and VSWR meter
The Inter-Power SWR-5 - upper right - "isn't worth a penny". Got it from a mate to use with a beacon, but I burnt it out with only 3.5-4W morse signal on 70cm. ...
Police and airplane reception tube reciever
The Philco radio is a nine tube superheterodyne reciever combining standard broadcast, police and airplane reception and employs the high efficiency 6.3 volt fi...
75 meters Band SSB transceiver
In general, the transceiver switches the 4-element 1500 ohm xtal BPF ends between the inputs and outputs of the two SA602s to reverse the signal flow for R/T op...
30m Band CW-Transceiver
This simple QRP transceiver for the 30 m band did not result from a detailed requirement profile. I simply had some NE592 broadband amplifiers in my junk box, w...
Tx/Rx Control
This circuitry offers some features that are highly desirable when building a QRP (or ANY) transceiver. It also includes a combination of features that many mig...
30m Band Receiver
The direct conversion receiver described consists of only a bandpass filter, mixer IC, VFO and audio filter. With only 22 parts, this simple circuit should take...
SWR Meter
A simple SWR meter first needs a calibration to Uv = 100 % (forward power). When switching over to Ur (reflected power) the SWR is indicated. This procedure has...