radi0 писал(а): ↑17 фев 2024, 12:55
The problem with a 5 v voltage booster is the parasites it produces, we must not forget that he installed an LNA in the rx. I think this is why the manufacturer of the asp25 AMP did not install the 5 v boost.
Hi,
Yes, all understood.
The modification that I made was just to add a low power charge-pump to the Digi Decode circuitry. This is what is used on the ATS120D decoder board. There will still be some conducted noise feedback to the battery supply and radiated emissions, so it is not ideal.
The logic level for the CW/RTTY decoder signal (without the 5V boost) can be fixed by changing the arrangement of the pull-up resistor on the LM567 output (see previous messages).
With the USB cable plugged in, the battery voltage will get close to 4.2V, but the charger chip is switched mode (for efficiency), so that will also create noise. Charging will not terminate when the receiver is switched on because the current does not drop to the cut-off threshold.
The ESP32 is marked "ESP32-WROOM-32U". The nominal operating voltage is 3V3 and the specified range is 2.7V to 3.6V.
As previously stated, the ATS25-AMP will generally operate correctly, so for the cost of the receiver and performance you will get, it’s probably best just leaving it as is.
73, Dave