Johnson's Techworld

In modern radio equipment, a rotary encoder is the digital successor to the old-fashioned tuning capacitor. While it looks like a standard volume knob, it functions as an

I was planning to use a refurbished desktop computer for my homebrew LMR SDR 1.1. But that computer became out of order and could not be recovered in

A gamma match is a popular method used to feed an unbalanced transmission line (like 50-ohm coaxial cable) into a balanced antenna element (like a dipole or the

Working with amateur radio satellites introduces a unique set of challenges compared to terrestrial communication. While you can use simple vertical or horizontal antennas, circular polarization (CP) is

I have two antennas which can work on 15m with the automatic antenna tuner in my FT-710 radio. Interestingly, I do not have to retune when I change

After the initial power on of the LCD, I have followed the instructions from VU3AVE regarding uploading of the hex file to the Arduino Nano: 1. First install

A 16 x 2 LCD display (16 characters, 2 lines) typically has 16 pins. But in the LMR SDR 1.1 circuit four pins (pins 7, 8, 9, 10)

The Berg connector, more commonly known as a Berg Strip or Berg Stick (also known as standard 2.54mm pin headers), is a highly popular connector used with Arduino for prototyping and connecting

All the resistors, capacitors and inductors have been mounted. Five integrated circuits on this side, 7809 regulator IC, 1N4148 diodes, 5V Zener diodes and all the relays have

അമേച്വർ റേഡിയോയിലും മറ്റ് റേഡിയോ കമ്മ്യൂണിക്കേഷൻസിലും വളരെ പ്രധാനപ്പെട്ട ഒരു അളവുകോലാണ് സ്റ്റാൻഡിംഗ് വേവ് റേഷ്യോ (Standing Wave Ratio) അഥവാ SWR. ലളിതമായി പറഞ്ഞാൽ, ഒരു റേഡിയോ ട്രാൻസ്മിറ്ററിൽ നിന്ന് പുറപ്പെടുന്ന ഊർജ്ജം (Power) എത്രത്തോളം കാര്യക്ഷമമായി