开云体育

Most of us don't have tones from the 16mhz Nano processor clock since that ceramic
resonanator is so inaccurate..
For those that do, just spend $3 on a different $3 Nano clone.
A bit tough on a v3 uBitx, as the Nano was not socketed until v4.
As of v4, the uBitx (and any Raduino) comes with the Nano socketed on the Raduino.
Note that the header pins must be on the "wrong" side of the Nano,
so order your Nano with header pins not yet soldered in place.
Shipping without the Nano clone would probably cost more in trouble than the clone does.
Give any spare clone away to some teenager bored with video games.

I have not exhaustively evaluated all the various possible sources of birdies
only addressed the ones I've heard to be problematic.

Anything that creates 12 or 45mhz will be problematic, as that can sneak into the
unshielded IF and create hetrodynes that always occur, no matter where you tune.
The 4'th harmonic of 12mhz beating with the 3'rd harmonic of 16mhz (if your
16mhz resonator on the Nano just happens to be 16.000mhz) is especially weird,
but if both 48mhz signals are present at the demodulator you will get audio tones.

Lots and lots of birdies that you can tune through.
You will likely hear a carrier at 25mhz, for example, from the si5351 reference oscillator.
But only when receiving at 25mhz.? ? Also the 16mhz Nano processor clock.?
But those (and many others) will only occur at specific spots on the dial.
Unplug the antenna and tune around your favorite band, see what birdies you find.

Jerry


On Mon, Dec 10, 2018 at 08:04 AM, <freefuel@...> wrote:

A) Hi Clark, yes I recall there was an issue with the full swing vs low power with the ATmega644p/ATmega1284p the oscillator was interfering with the serial port in full power mode, it made for interesting times trying to use a serial bootloader.

that said changing the fuse bits in the NANO is very easy with the ATMEL ISP programer, step 1) make a backup copy of the firmware, eeprom, and fuse settings. 2) update the fuse settings from their current state to place the device in low power clock mode. 3) verify firmware, eeprom, and new fuse settings.?

B) Jerry, did you run the numbers for other common catalog crystal frequencies? for example, would running the AVR at 11.052MHz and leaving the IF at 12MHz be a viable option???

-Justin N2TOH

P.S. Ashhar?as an option could a person order the Randino with the NANO uninstalled? some people including myself need the real FTDI USB chip, the other types cause unresolvable usability problems.? the drivers for the chip provided in my kit rendered my Macintosh unusable, I had to use a 3rd party keyboard and mouse to recover the settings.??