oh, yes, you’re right, I see that upon closer inspection

Could it be that the voltage doubler, D8 and D9, doesnt provide enough DC-voltage for the switching diodes to keep them turned on during the entire transmit period?

Perhaps this clock based on Arduino Mega and a GPS like the QLG2 will meet your needs? It has more than 30 different clock screens, https://github.com/la3za/Multi-Face-GPS-Clock

You should check out the u3s-eeprom-tool which has been discussed on this list a while ago, e.g. https://groups.io/g/QRPLabs/topic/28443433#28847

One may use the RX mode to insert breaks between transmissions. See my ‘Third’ point in this blog post: https://la3za.blogspot.com/2021/07/coordinated-wspr-band-hopping-with.html

If you are impatient to get sunset/sunrise and moonset/moonrise and don’t mind connecting up an Arduino Mega, a display and a few other components, then my GPSClock which is available on GitHub has th

#firmware #clock

I wrote up the considerations that need to be taken into account when implementing the WSPR band hopping schedule on the U3S: Frequency stability Time for frequency calibration How to deal with inacti

#u3s

I should add that the recommended band hopping sequence is from low to high frequency: 160m, 80m, ..., 10m (10 bands). This is the opposite order of what used to be recommended for the U3S for maximum

#u3s

Hi Ken Thanks for your comment. First, you say it is good practice to follow the band hopping sequence, but do we have actual evidence that people with receivers are more likely to listen at these spe

#u3s

I have made a setup for my U3S where I follow the WSPR band hopping sequence which is recommended by K1JT. It is as follows: Band (m) 160 80 60 40 30 20 17 15 12 10 UTC Minute 00 02 04 06 08 10 12 14

#u3s

👍

#u3s #tcxo

Most likely, but I don't have anything to compare with. But I got it just a few days ago and when I ordered it, there was a message saying that there was a delay in shipping.

#u3s #tcxo

I got my 25 MHz TCXO module in the mail the other day. It works like a charm and is a must-have for perfectionist like me who just can't bear seeing drift reports of 1,2,3, or 4 Hz/min in the WSPR rep

#u3s #tcxo

I use the cheap 2596 converters for my U3S also and the work well. But there is something suspect about them. Mine have switching frequencies around 50 kHz, but an LM2596 is supposed to switch at 150

I agree cell phone chargers are good for what they are intended for, but may be too noisy as a power supply driving e.g. an U3S. On the other hand, many have found, like I, that the switch-mode power

#u3s

I'm using regulators based on the L;2596, cheap on Ebay. A fixed one for the processor and a variable one for the PA.. See https://la3za.blogspot.com/2017/02/comparing-two-antennas-with-wspr.html

#u3s

There is a bit that can be set on the U3s. It is used to change antennas in my U3, https://la3za.blogspot.com/2017/02/comparing-two-antennas-with-wspr.html If one output is attenuated, and the two out

#u3s

The solution to the problem I had of drift with the OCXO was much simpler than I had thought: To my embarrassment connecting the heater to + 5 Volts made all the difference! It turned out that I had d

#ocxo #u3s

I'm afraid I've tried this. The calibration is now set to Step 01, Time 060, but the step size was larger initially. The frequency has more or less stabilized to 26,998,733 which should be about right

#ocxo #u3s

Hi Andy, Thanks for the reply. Yes, I set up just like you describe. But I am still afraid that I didn't quite hit the sweet spot because of the drift I am seeing. The fact that I am seeing negative v

#ocxo #u3s