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Monthly archives: January, 2022

Circuit – FM Bandstop Filter for RTL SDR

fm trap

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 …

DIY – Making printed circuit boards

pcb making

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 …

Circuits – 7MHz CW / AM QRP Transmitter

7MHz CW / AM QRP Transmitter  – D.Prabakaran The circuit of a 7MHz C W / A M QRP transmitter described here can be used to transmit either CW or audio frequency modulated signal over a 7MHz carrier. The carrier frequency oscillator is crystal controlled using 7MHz crystal in its fundamental mode. The tank circuit …

Video – NOAA19 weather satellite reception with experimental V dipole antenna

noaa19 weathersat reception HDSDR

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 …

Circuits – Offset tuning indicator for CW

MORSE KEY

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 …