Hello, John, I have 2 USB battery packs. They both turn themselves off after a while if the load is light. I don't know what that threshold is. So, it'll probably work for at least a little while. Che

I added another WSPR transmission to the WM2XCW 8m propagation beacon. I figured I would have to adjust the clock frequency setting because the unit would now be sending two WSPR transmissions instead

#u3s #clock

Hi David, When comparing the a-Si (amorphous silicon) and c-Si (crystalline silicon), consider the power vs. mass needs for your flight. My calculation, which also considers the temperature coefficien

I ordered my U4B a week ago. At USD $33 per gram, it's a great deal! While waiting for it to arrive, I bought an HT-37 (29,700 grams) for USD $0.00393 per gram. For some reason, I thought it was a goo

Hi Tony, Assuming your solar cells are mono- or multi-crystalline silicon, they'll provide a higher voltage when cold (approximately +0.3% per degree C) and less current, approximately -0.06% per C. A

Hi Mark, This is only a guess, because I didn't write the program: I suspect that to be included in the TX list, there would have to be many receivers receiving and uploading spots from a particular t

#u3s

Yesterday, I used Spectrum Lab to take a close look at the WSPR transmission spectrum. This confirmed that WSJT reports the frequency as that of the spectral centre of the WSPR transmission. By lookin

#u3s

Hello... I made a semi-satisfactory workaround. I am now sending CW information with ID and location in one CW transmission and a "T" in a QRSS transmission immediately after. The dit length is 10 sec

Hi Mark, I think it may be in the receiver or the receiving computer's sound card. One way to tell is to look for other stations that also receive the fundamental signal strongly. Is the 120 Hz spur d

#u3s

An update: I tried removing all material after the *300* in the message. I also tried it in FSKCW mode. It is still stuck, repeating the message until I press the left button to switch to configuratio

Hello, Hans, Thanks for that answer. I had skipped that part of the instructions because I thought the feature was available only in FSK/CW mode. But now I have another problem. I created a message li

Hi Bill, Just install a TCXO on the synthesizer board in place of the 27 MHz crystal. It'll set you back about $3. Some TCXOs adjust their frequency in steps, and those steps become very significant w

#wspr

I wanted the ability to turn my beacon transmitter off remotely, via internet. It appeared that an ESP8266 module could probably do this, but my brain feels too full to learn to code on yet another pl

#10W_PA

Don, Can this be as easy as a 5k resistor in series with a 50 ohm resistor connected across the signal I'm trying to measure? Both resistors would be low-inductance thick film types, of course. I'm th

#10W_PA

I installed the U3S, 10 W Linear PA (original ferrite cores), and a PCB with T/R relay, voltage regulator, and PA power switch into an aluminum box. I have an LPF filter on the U3S and another one at

#10W_PA

I forgot piece of context information: I use the U3S' PTT line to turn the PA bias on and off instead of leaving the bias on continuously. The PTT line feeds a 3.3V regulator so that the bias voltage

#u3s

Hello, all... I’m using my U3S in CW mode with the 10W Linear PA, which does not have the clever cosine rise and fall profiles of the 5W PA. I wish to reduce the key clicks. I’m thinking of adding a c

#u3s

Hi Dale, There are many inexpensive TCXOs at Digikey and Mouser. I see ECS-TXO-5032MV-250-TR in stock at Digikey for less than $2 USD. Cheers, Halden

Thanks, Allison! This power measurement is after the low-pass filter I've connected to the output. My NanoVNA says that filter's quite good - suppressing the first few harmonics by more than 50 dB. Wi

#10W_PA

My 10W Linear PA kit gives 12.2W output while drawing 1.5A at 13.0V from a LiFePO4 battery at 40.7 MHz. This works out to 63% efficiency, which seems a bit high. Is this actually a realistic operating

#10W_PA