Re: burst of harmonics during CW key-down?

Adrian Chadd

.. (and morning hackery - i hit send too quickly.)

I measured the RF output but I didn't measure the time it takes to gate the si5351. I have a bunch of breakout boards so I can go do that measurement separate from the ubitx and tweak that constant later. The bitx40 just sleeps for 65ms when turning on. I elected to split it up into two #defines so we can tweak each phase later on based on actual measurements.

Ok, now I'll get coffee. ;-P


On Thu, 18 Apr 2019 at 03:25, John (vk2eta) <vk2eta@...> wrote:
Thank you Adrian.

I also noted this affects my V3 uBitx and I will apply the mods to my customized version.

I am just surprised that a delay of 15ms is necessary after sending the clock shutdown command, presumably for the si5351 chip to stop its clock.

That's a 67Hz on/off max frequency and seems out of proportion with the clock frequencies generated (lowest is 3.5MHz in CW mode for the stock version) or even when compared with the transmission of the 8 registers needed to program the si5351 clock frequencies over the i2c bus which should take less than 1ms per clock.

I must be missing something.

The 30ms for the relays/TX power stabilization make sense to me on the other hand,

Best 73, John (VK2ETA)

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