The T41-EP is a Software Defined Transceiver designed by Albert F. Peter, AC8GY and Jack Purdum, W8TEE. The “T41” part of the designation comes from the fact that it uses the Teensie 4.1 microprocessor for software processing. The “EP” part of the designation means “Experimental Platform.” I started building Version 10 of the radio a couple of months ago, while Jack and Albert are now well off into version 12. Experimental — evolving.
The 4SQRP version of the T41-EP uses a 5″ LCD and enough front panel controls that one doesn’t have to be constantly digging through menus. That grid of buttons on the right gives instant access to many menu pages.
The picture is from the T41 site, not my build.
My interest is not the 20W capability, but the 15M, 12M, 10M capability. I’ll strick to QRP power levels, but want the rig for the bands. Yes, I have those bands with the “quirky Lil Orange” (tr)uSDX, but I trust the T41 will have more pleasing audio quality, and much easier operation.
While the designers create circuits, PCB layouts and such, it is up to builders to either collect their own parts or find groups that are collecting parts for sale. One such group is the Four State QRP Group, 4SQRP, located in the Ozarks region of the U.S. A little over a year ago, they began a kitting operation to both promote the T41 and as a fund raiser for their club attending the OzarkCon ham radio conference. One interesting aspect of their sourcing is the provision of Printed Circuit Boards (PCBs) that already have the tiny Surface Mount Devices (SMDs) installed. Buyers are relieved of needing to acquire SMD assembly techniques. It was my very good fortune to snag a kit near the tail end of their run, which I think was 150 units plus a few betas. It arrived a few months ago and has not yet self-assembled.
My first job was making a “jig” to hold circuit boards. I think there are 7 or 8 in the kit. Instead of buying a fancy-looking collection of plastic, I wandered out to my woodworking shop, picked up a 2×2 cutoff, cut a very accurate kerf with my kerfing plane, and cut it into 2 pieces. Done!!! no waiting for Amazon.
The first assembly task is the power supply regulation board. It was an easy way to start and is now done and tested. AOK!
The assembly manual, about 120 pages, is concise and includes circuit diagrams, bills of materials, suggested build sequences, and in some cases test procedures.
A more extensive document, Software Defined Radio Transceiver: Theory and Construction of the T41-ep Amateur Radio SDT, is a 497 page book by the designers, and is a full fledged tutorial on digital signal processing using the T41 radio as the basis. It too holds extensive build and test advice.
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