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Hi there, I made a frequency reference using a NEO-7M controlled by a NANO. It was esssentially the design by Louis Skully, and members might find it useful to refer to

The upper frequency is at least 10MHz. Above that it could work and there could be jitter. A trippler seems safer. -- HBTE Files section: /g/HBTE/files Erik, PD0EK

Datasheet states: "Timepulse Configurable 0.25 Hz to 10 MHz" So I guess that is an undocumented feature? Do you know if the same is true for the 8M? I found some fairly cheap M8N modules so thinking

It's amazing what's out there in cheap easy to use prototyping modules these days! Jerry

The NEO-7M can output a GPS locked 30MHz. -- HBTE Files section: /g/HBTE/files Erik, PD0EK

I doubt the MMIC of the circuit used by w1vd is required here, the Si4432 already has a high gain amp to make the 30mhz crystal oscillate. So just a couple diodes plus some caps and coils, here's a

Cheaper alternative, since it does not require any additional hardware, would be to feed the output (simple wire as antenna would probably be sufficient) to a receiver 1KHz up or down from some on air

Interesting, good to know how accurate the Si4432 is, and how to correct it. Any error in the frequency of an Si4432 will be due to the 30mhz crystal reference oscillator. The ideal would be to

The xco's in the SI4432 modules are not very well calibrated and also rather temperature sensitive. But how to calibrate the tinySA so measured frequency are correct and the signal generator is not

As far as I am aware of there are no readily available H-mode mixers that will accept input between 433MHz and 900MHz As they are based on switches they have limitations on the switching speed -- HBTE

Probably a really dumb question but did you try the "H-Mode" mixer? Not sure what the frequency range of that topology is and it probably won't be any cheaper since it requires transformers (unless

The mixer in the tinySA is a relative expensive part and it is obvious to see if cost can be reduced by using for instance an active gilbert cell mixer such as the IAM81008. One big advantage is the

"Bluepill" is really simple with PlatformIO (plugin for VSCode editor). Pair that with STLink clone (~$2), or another bluepill with blackmagic probe and you get a proper debugger, no need for a boot

There is nothing in the Arduino SW that requires strict timing (when using HW interrupts for the rotary encoder) Scanning may be a bit slower but it should work. Best if you try to compile the

Erik, I long ago standardized on using standard Arduino nano boards (5V). For my build I plan to use one along with cheap bi-directional level translator boards. 5V Arduinos use an 18MHz clock whereas

Using the GPIO2 output of the LO SI4432 it is possible to create a fairly accurate -30dBm power reference level as the output swing of the GPIO port is 3 Volt when the current is below the drive

Finding 3.3V compatible Arduino boards is bit more difficult than the good old Uno or Mega. There is a nice overview of all Arduino boards with their features including the input/output voltage.

Temp and Vdd could be responsible for most of the possible variation in GPIO current. But the datasheet doesn't tell us. Mouser sells the Si4432 by the 2500 piece reel at $4.19 each. Makes me wonder

Thanks for these calculations. I tried the circuit you proposed. capacitor + 1k5 + 50 ohm to ground. Switched GPIO2 to maximum drive capacity. Output voltage measured with calibrated scope terminated

Eric, A free reference level is an excellent addition. Accurate measurements across 1 to 30 mhz is sufficient for many of us. Page 12 table 7 of the Si4432 datasheet shows that the GPIO outputs can be