Monthly Archives: September 2025

BeaconBlaster, FST4W, New Stuff, WSPR, WSPRSONDE

Digital One Watt Power Amplifier

Turn your logic-level outputs into slightly more powerful signals! This design is one I have been using in the WSPRSONDE, and I’ve found it to be so useful that I put it in a little box along with a USB C power connection and a couple of indicator LEDs.

This will require a low-pass filter to convert the square wave output to a spectrally-pure-meets-all-FCC-regulations signal, but that’s pretty simple. This design easily covers all the ham bands between 160 and 6 meters.

TIS-1W Digital 1W Power Amplifier

Equipment using this amplifier circuit has been continuously transmitting for several years, from the steamy jungles of Costa Rica to the frozen wastes of the Arctic and Antarctic, The design and performance is thoroughly described in the product guide.

FST4W, Power, RX-888, SDR, WSPR

Glitchless Power with the TIS-1250

This is another design inspired by and adapted from a KA7OEI project:

https://ka7oei.blogspot.com/2025/01/a-short-term-ups-for-mini-nuc-type-pcs.html

We’ve seen that that the small computers used in wsprsonde (and other) receive installations will reset or hang up during power outages, even when there is a UPS between the utility power and the computer’s power brick. It turns out that many UPS units have a momentary dropout when they transition to backup mode, and the brick power supplies do not have enough internal storage to ride through this transition. This is bad enough in home operation, but especially problematic in a remote installation with limited access.

There are certainly glitchless UPS products available (“on-line” UPS), but these are more expensive and sometimes “glitchless” really isn’t.

The TIS-1250 provides an alternative solution, by using a “supercapacitor” (1.25 Farads) and low-loss charging / discharging circuitry.

See more details here:

TIS-1250 SuperCap UPS