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

I just assembled an OCXO and have had it running for a few days with the U3S at 18 and 14 MHz. The U3S is in the QRPLabs enclosure. It turns out that I need to have the lid off in order to reduce drif

#ocxo #u3s

I agree Hans, the extended-mode should be avoided - and thanks for the link to code! 73 Sverre LA3ZA, http://la3za.blogspot.com

#u3s

I recently experienced something strange on WSPRnet. I started seeing what I thought were pirated transmissions with my call sign, coming from a different six-digit locator, but the same 4-digit locat

#u3s

Thanks for posting these pictures. I didn't know that these 1 USD relay modules were available. They enable several possibilities for switching in 5 W PAs, switching between antennas etc. Re the criti

Just discovered that my U2 can do audible frequencies. Time to wipe the dust off it.

#u3s

Yes, true - it's letters coded in ultrasonic audio which is received by anyone's smartphone using any of many different spectrogram programs that are available for iPhone or Android. 73 Sverre LA3ZA,

#u3s

Thanks Hans, Yes I guess that as long as 137 kHz is covered, amateur radio bands are ok. If you should need a little project on the plane to FDIM, and if it is only a matter of redefining a value for

#u3s

I saw a nice demo the other day of secret messages sent over ultrasound by a speaker. It was received by spectrogram software on smartphones. It was a nice demo that was used to get school children in

#u3s

Yes, Alan, good point. On the other hand the step-down module doesn't cost much more than a series diode. But it must of course be replaced every time something goes wrong, like a fuse, unlike a serie

#u3s #supply

I was unfortunate enough to apply 12 Volts with a reversed polarity to my U3S recently. Lucky for me, the LM2396 step-down voltage converter that is responsible for the 5 Volts for the processor handl

#u3s #supply

Thanks - got it to work, using what you said. But I had to install intelhex per user, not system by the command >py setup.py install --user The editor looks nice!

Thanks. Being a total novice with Python, it seems to stop when trying to install intelhex. I've got the library, but it won't install. So trying to run t he editor naturally gives this error: >py eep

I really would have liked to try out this editor, but I am not familiar with how to run it under Python on my Windows PC. Any recommendations, like which Python installation to use? 73 Sverre LA3ZA, h