DIY Antennas, QRP, SDR & Ham Radio Projects from VU3DXR
FM Bandstop Filter for RTL SDR The given FM band stop filter is nothing more than a simple Band stop filter for the frequency range of 88-108Mhz. FM Broadcast transmitters transmit at high power and can cause overloading and intermodulation problems on simple receivers like RTL-SDR due to its wide open front end. The said […]
Simple zener diode tester Ever found yourself with a handful of zener diodes, wondering if they’re still good or what their actual breakdown voltage is? Zener diodes are incredibly useful components for voltage regulation, but sometimes, their markings can be ambiguous, or you just need to quickly verify their functionality. That’s where a simple zener […]
Making printed circuit boards There are many ways to produce your own printed circuit boards. Small boards for DC switching circuits are easy to make because neither the size nor the shape of the copper foil traces is critical. Boards containing many digital ICs are considerably harder to lay out and etch. There are also […]
Colombo International Radio Tamil service – Inaugural day transmissions Frequency – 873khz Time – 7.00 am to 8.00 am The 872 kHz frequency represents a fascinating chapter in the story of Tamil broadcasting from Sri Lanka, though the actual frequencies used by the Sri Lanka Broadcasting Corporation (SLBC) for their international Tamil service are slightly […]
Build a versatile 7MHz QRP Transmitter capable of both CW and AM modulation. This DIY guide features a stable 40-meter crystal oscillator, a class-C power amplifier, and simple switching for dual-mode amateur radio operation.
VWN Vasanth HF net Reception at 7123.4 khz RX Hardware – MSI SDR Dongle Antenna – 66 Feet EFHW The VWN Vasanth HF net operating on 7123.4 kHz represents part of the vibrant amateur radio community in South Asia. This frequency falls within the 40-meter amateur band, which is ideally suited for regional communications across […]
Charminar net at 7080khz RX Hardware – MSI SDR Dongle Antenna – 66 Feet EFHW The Charminar Net operating on 7080 kHz stands as one of the prominent regional amateur radio networks in Southern India, serving operators across Kerala, Tamil Nadu, and Andhra Pradesh from 7:30 to 9:00 AM. Named after the iconic Charminar monument […]
Beautiful images received from NOAA19 weather satellite with experimental V dipole antenna Location – Krishnagiri, Tamilnadu, India Receiving Hardware – RTL SDR with experimental v dipole antenna. Receiving NOAA-19 Automatic Picture Transmission (APT) signals presents an exciting opportunity for radio enthusiasts to explore satellite communications while experimenting with antenna designs. The V-dipole antenna configuration offers […]
NOAA19 weather satellite reception with experimental v dipole antenna Date – 18.01.2022 Location – Krishnagiri, Tamilnadu, India Receiving Hardware – RTL SDR with experimental v dipole antenna. NOAA 18 and NOAA 19 weather satellites provide free accessible weather data continuously through Automatic Picture Transmission at 137.9125 MHz and 137.1000 MHz frequencies. RTL-SDR TUTORIAL: RECEIVING NOAA […]
An NE567 tone decoder, tuned to the transceiver`s CW offset frequency, ensures that the transceiver will be transmitting on the same frequency as the received CW signal. Simply tune the transceiver so that the LED lights. Eight to 13 Vdc is required; this can be taken from the transceiver supply or an extra battery. Audio […]