DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
The LM1458 is a dual operational amplifier (op-amp) that finds applications in audio amplification and other circuits. Let’s explore how you can create a simple Microphone compressor using the LM1458. To get greater transmitting performance from your ham radio transceiver, we need to keep the modulation level constant, regardless of your voice level. With the compressor […]
This microphone compressor circuit utilizes a two-stage amplification design for dynamic range control. Initially, the input signal enters through MK1, a microphone input connector. Subsequently, the signal passes through C1 and C3 coupling capacitors for DC blocking. The first amplification stage employs Q1, a 2N3904 transistor configured as a common emitter amplifier. Meanwhile, R1 provides […]
Simple audio compressor for SSB HF Radio rigs An audio/speech compressor is a device that reduces the dynamic range of the audio signal. This means that it makes the loud parts of the signal quieter and the quiet parts of the signal louder. This can be useful for SSB HF radio rigs because it can […]
NE555 based Microphone amplifier IC NE555 or commonly known as 555 is an IC that is well known among electronics practitioners as an IC for timers, and can be used to form monostable or bistable multivibrator circuits. But not many know that the 555 IC can also be used as an audio signal amplifier. By […]
Amateur Radio – End fed Halfwave antenna – Web resources and links An end-fed half-wave (EFHW) antenna is a type of radio antenna that is a half-wavelength long and has its feed point at one end. This makes it a very simple and compact antenna, and it is often used for portable or temporary applications. […]
Audio processors and Speech compressors are important in SSB radio because they can help improve the transmitted signal’s quality. Here are complete resources and links available in the internet connected to Mike Preamplifier/Speech compressors/Speech Processors Dyna Audio compressor Noise Canceling Electret Microphones – WB9YBM Microphone Speech Processor Microphone Amplifier with ALC Audio compression with transistors […]
A short linear loaded ham radio band HF antenna is a type of antenna that uses linear loading to reduce its physical length. Linear loading is a technique that involves adding parallel conductors to the antenna elements. This increases the antenna’s effective length, allowing it to operate at a shorter physical length. Short linear loaded […]
This 80M Trapped dipole antenna is the work of Nadisha 4S7NR, modified by YC0HLE which results are matched at a frequency of 3,845 MHz. This design will be resonant at a frequency of around 3,250MHz to 3,850MHz. Coil inductance = 67.83 µH, made of email wire diameter = 1 mm, diameter of the cocker = […]
SSM2167 audio processor for Baofeng Mic enclosure Mic gain is barely adequate on the µBITx transceiver since there is no Mic Gain control. It would also be helpful to not only provide mic gain control, but to add compression in order to boost the average power output.The SSM2167 is a powerful audio processor that can […]
Modified simple horizontal V antenna This antenna is little modified version of antenna designed by Adam 9A4QV for noaa/METEOR Weather sat reception. Adams antenna is based on a very simple linearly polarized dipole, which makes construction almost trivial. I tried his antenna and found that practical difficulties in finding choc block terminals. Chock block terminals are not strong enough […]