Difference between revisions of "VFO-001"
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** Programmed via Arduino IDE | ** Programmed via Arduino IDE | ||
*** Download via serial | *** Download via serial | ||
| + | ** Store configuration in EEPROM | ||
* [[Si5351 Oscillator Breakout Board]] | * [[Si5351 Oscillator Breakout Board]] | ||
** 10 KHz - 40 MHz tuning range | ** 10 KHz - 40 MHz tuning range | ||
| Line 71: | Line 72: | ||
** 1Hz, 10 Hz, 100 Hz, 1KHz, 10KHz, 100 KHz, 1 MHz, 10 MHz | ** 1Hz, 10 Hz, 100 Hz, 1KHz, 10KHz, 100 KHz, 1 MHz, 10 MHz | ||
* Set frequency | * Set frequency | ||
| − | ** 10 | + | ** 10 KHz to 40 MHz in step size steps |
* Select VFO | * Select VFO | ||
** VFO0, VFO1, VFO2 | ** VFO0, VFO1, VFO2 | ||
| Line 80: | Line 81: | ||
* Set Calibration Value | * Set Calibration Value | ||
** In step size steps (down to 1 Hz) | ** In step size steps (down to 1 Hz) | ||
| − | * Save | + | * Save (power-on) defaults |
=== Libraries used in this app === | === Libraries used in this app === | ||
| Line 107: | Line 108: | ||
<video type="youtube">QCJ4cQGOQLI</video> | <video type="youtube">QCJ4cQGOQLI</video> | ||
| − | == | + | == Output Drive Level == |
| + | |||
| + | * First, calculate the "theoretical" drive level and then measure the actual drive level into a 50 ohm load | ||
| + | |||
| + | === Si5351A Drive Level === | ||
| + | |||
| + | * Si5351A drives 3.3V square waves | ||
| + | * Si5351A datasheet lists 50 Ohm source impedance | ||
| + | ** Half of the power would be dissipated in the source and half in a 50 ohm load | ||
| + | * The RMS value for square-wave voltages whose pulse duration (ti) and pause (tp) have the same length: | ||
| + | |||
| + | [[file:RMS-SquareWave.PNG]] | ||
| + | |||
| + | * [https://www.redcrab-software.com/en/Calculator/Electrics/Rectangular-Voltage-RMS-Value#:~:text=The%20rms%20value%20is%20for%20square-wave%20voltages%20whose,rms%20value%20is%20equal%20to%20the%20peak%20value Square Wave Calculator] | ||
| + | |||
| + | [[file:RMS-SquareWave-2.PNG]] | ||
| + | |||
| + | * Using a "theoretical" drive level of 3.3V | ||
| + | |||
| + | [[file:Si5351_Drive-Level_dBm.PNG]] | ||
| + | |||
| + | * [https://www.calculatorology.com/mw-to-dbm-conversion/ 54 mW is 17.3 dBm total power] | ||
| + | * Half delivered to load = 27 mW | ||
| + | ** 14.3 dBm "theoretical" drive level | ||
| + | * [[Kits_and_Parts_Mixers#VFO-001_drive|ADE-1]] needs +7 dBm drive level | ||
| + | * Would in theory need a 7 dB attenuator between the Si5351A and the [[Kits_and_Parts_Mixers#VFO-001_drive|ADE-1]] | ||
| + | * Reality, the output drive in the Si5351A is controlled by the output drive control register | ||
| + | * Si5351A outputs as measured with [[tinySA]] | ||
| + | ** Drive Level 2 mA = 0.2 dBm | ||
| + | ** Drive Level 4 mA = 6.2 dBm < Best choice for driving +7 dBm mixers like the [[Kits_and_Parts_Mixers#VFO-001_drive|ADE-1]] | ||
| + | ** Drive Level 6 mA = 9.7 dBm | ||
| + | ** Drive Level 8 mA = 11.7 dBm | ||
| + | |||
| + | === Measured === | ||
* Channel CLK0 | * Channel CLK0 | ||
* 10 Mhz | * 10 Mhz | ||
* 30 dB external attenuator (gain set in tinySA to -30dB) | * 30 dB external attenuator (gain set in tinySA to -30dB) | ||
| + | * Output level at 2 mA | ||
* Scan 1MHz to 300MHz | * Scan 1MHz to 300MHz | ||
| Line 120: | Line 155: | ||
[[file:tinySA_VFO-001_10MHz-Signal_Narrow-10MHz.png]] | [[file:tinySA_VFO-001_10MHz-Signal_Narrow-10MHz.png]] | ||
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== Videos == | == Videos == | ||
Latest revision as of 13:42, 1 November 2021
Contents
Features
- SDD1306 OLED Display
- I2C Interface
- OLED runs from 3.3V (can run from 5V but this use has 3.3V)
- Rotary Encoder Break Out Board
- Arduino Pro Mini
- Arduino compatible
- 3.3V
- 8 MHz
- Programmed via Arduino IDE
- Download via serial
- Store configuration in EEPROM
- Si5351 Oscillator Breakout Board
- 10 KHz - 40 MHz tuning range
- 1Hz/10Hz/100Hz/1KHz/10KHz/100KHz/1MHz/10MHz steps
- I2C Interface
- 3 Outputs
- 27 MHz crystal
- 3.3V operation works without level shifters for I2C*
- Si5351 can only run from 3.3V
- Used right angle headers and Dupont cables for low profile
- 10 KHz - 40 MHz tuning range
- Mini-360 Buck Regulator
- 5V-23V input
- 3.3V output
- Extruded Aluminum Enclosure Box - 94mm x 83mm x 30mm
Schematic
- PWR* - connect only when no Mini-360 Buck Regulator is used
- PD01 - Power Distribution card (not shown)
Build
- Extruded Aluminum Enclosure Box - 94mm x 83mm x 30mm - Out of stock
- BNC/Power Jack placement
- Rear panel BNCs and power jack
- Drill holes and nibble out for OLED cutout
- A bit rough
- Better to undercut nibble and file to size
- OLED fitted
- Final
Libraries/Example Code
Land Boards Code
VFO Menu
- Set Step Size
- 1Hz, 10 Hz, 100 Hz, 1KHz, 10KHz, 100 KHz, 1 MHz, 10 MHz
- Set frequency
- 10 KHz to 40 MHz in step size steps
- Select VFO
- VFO0, VFO1, VFO2
- VFO On/Off
- On, Off
- Drive Level
- 2 mA, 4 mA, 6 mA, 8 mA
- Set Calibration Value
- In step size steps (down to 1 Hz)
- Save (power-on) defaults
Libraries used in this app
- U8g2: Library for monochrome displays, version 2
- Si5351 Library for Arduino
- Rotary Encoder - Software debounced
Other Si5351 Libraries
- Universal Digital VFO Si570/Si5351
- Adafruit_Si5351
- Si5351 Library for avr-gcc
- vk3hn_VFO_controller
- Simple BFO with si5351 controlled by Arduino
- VFO and BFO with Si5351A, OLED and Arduino
Calbration Using WWV
- Good method that doesn't require a frequency counter
- Tune via ear and S meter
- Requires shortwave (or ham) receiver that can receive 5/10/15 MHz
- Rough tune calibration factor on scope or frequency counter
- Fine tune to 1 Hz using WWV
- 15 MHz WWV midday has better resolution
Output Drive Level
- First, calculate the "theoretical" drive level and then measure the actual drive level into a 50 ohm load
Si5351A Drive Level
- Si5351A drives 3.3V square waves
- Si5351A datasheet lists 50 Ohm source impedance
- Half of the power would be dissipated in the source and half in a 50 ohm load
- The RMS value for square-wave voltages whose pulse duration (ti) and pause (tp) have the same length:
- Using a "theoretical" drive level of 3.3V
- 54 mW is 17.3 dBm total power
- Half delivered to load = 27 mW
- 14.3 dBm "theoretical" drive level
- ADE-1 needs +7 dBm drive level
- Would in theory need a 7 dB attenuator between the Si5351A and the ADE-1
- Reality, the output drive in the Si5351A is controlled by the output drive control register
- Si5351A outputs as measured with tinySA
- Drive Level 2 mA = 0.2 dBm
- Drive Level 4 mA = 6.2 dBm < Best choice for driving +7 dBm mixers like the ADE-1
- Drive Level 6 mA = 9.7 dBm
- Drive Level 8 mA = 11.7 dBm
Measured
- Channel CLK0
- 10 Mhz
- 30 dB external attenuator (gain set in tinySA to -30dB)
- Output level at 2 mA
- Scan 1MHz to 300MHz
- Zoom into 10 MHz fundamental
- Approx. 1 dBm signal level
Videos
