113 Wickerberry Lane, Madison, AL 35756: [email protected] An Arduino Controlled GPS Corrected VFO A VFO that provides 1 to 112.5 MHz signals on two independent outputs. Use it as a stand alone unit or with a GPS receiver to improve frequency accuracy. UTC and six digit grid square locations are also displayed in the GPS Mode

The front end and VFO are presented in Fig 2. I initially used a VFO variable capacitor with a vernier drive mechanism. Problems occurred with the mounting, however. The VFO was rebuilt without a vernier. Instead, two capacitors were used.

Considering the size of most HF ham bands, a VFO needs a tuning range of at least 0.5 MHz. The higher the basic frequency of the VFO, the wider the tuning range you can achieve. ARRL handbook VFO projects have various frequencies ranging from 1.75 to 9 MHz. My CW transmitter VFO ranges from 3.5 to 4.0 MHz.

The VFO The oscillator (Fig 47) is a good exam- ple of the principle that a circuit need not be complex to work well, if properly designed. This simple Hartley circuit ex- hibits less than 200-Hz warm-up drift, with about half of that within one minute after turn-on. This drift performance is com- pletely repeatable, as shown by the build-

/* Arduino Controlled GPS Corrected Dual Output Si5351A VFO A VFO project that uses an Arduino Uno or Nano to control a SI5351A clock generator breakout board. The VFO may be used in stand-alone mode or with a GPS receiver to software calibrate the output frequency.

This sketch implements a three band VFO using the SI5351a; breakout board from Etherkit. Features include: Operation on a single frequency at a time, push button selected; Frequency adjustment by rotary encoder. Rate of adjustment is; push button adjustable in 10 to 10000 Hz increments. Display shows currently selected VFO, VFO status, VFO ...

2008年7月14日 · What follows here are descriptions of three different VFO circuits. The FET, a transistor low-noise design, and the NE602 used as a VFO. I have built and used them all except the transistor low-noise design. My favorite is the NE602, which I use in almost all my equipment where I need a 10 to 14MHz VFO.

VFO / Display / SWR Measurement Input Gordon Gibby KX4Z April 2018 INTRODUCTION The groundbreaking bitx-series of extraordinarily inexpensive low-power HF single sideband and CW transceivers have made impressive usage of the Si5351 frequency generator chip, …

Over the years, many amateurs have copied PAøKSB's method and in Februari 1996 Klaas published an improved version in ARRL's QEX magazine; also published in the Dutch magazine "Electron" in December '96. At that moment I was trying to minimise the drift of the VFO (5-5,5MHz) in my homemade QRP RTx.

Arduino code and circuit board files for "An Arduino Controlled GPS Corrected VFO." Gene Marcus: W3PM / GM4YRE: 7x15_Severns.zip: 7/2015 "Radiation and Ground Loss Resistances in LF, MF and HF Verticals: Part 1" Appendices A, B, C, and D are presented here as Microsoft Word document files for download. Rudy Severns: N6LF: 5x15_Fernandes.zip: 5/2015