Quote:
Originally Posted by Ian - G4JQT
That's a very interesting write up David.
Buzz, how close is your circuit to Wellbrook's? Is the circuit of the Wellbrook loop known? I assumed it was a commercial secret - or at least the more subtle aspects of the design - although I expect the Wellbrook loop to follow conventional loop antenna design.
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Yes, the 'Wellgood' is a clone of the Wellbrook, except that the Wellbrook, surprisingly perhaps, uses stripboard whereas the Wellgood uses a PCB. As I mentioned in the other thread, Dr George Smart, M1GEO, had accidentally transmitted into his WellBrook ALA1530 Loop and killed it. George had been very impressed with the Wellbrook so decided to see if he could repair or replicate the amplifier.
A friend of George’s - Dave G7UVW - who works in an X-ray lab, was able to X-ray the Wellbrook amp (encased in potting compound) to assess the feasibility of replicating it. From the X-ray images it was apparent that the amp was made on Veroboard, with several capacitors, ferrite transformers, and two transistors, identified as being ZTX327.
From his ‘teardown’ of the Wellbrook, George Smart designed a ‘clone’ amplifier built on a neat compact PCB rather than stripboard. He named it the ‘Wellgood’ and outlined his ‘teardown’ of the Wellbrook in detail and the subsequent design that he developed. The circuit, full constructional details, including winding the two small binocular ferrite transformers, even the bill of parts with RS part numbers is on his website and I believe he is also able to supply PCBs, so for anyone who wished to build a ‘Wellgood’ with the minimum of hassle, head on over to Geoge’s website.
The ferrite transformers, the design of the PCB, the development of the project and other aspects are all George's work so it isn't identical to the Wellbrook. Here’s the link to George's website, where you can see the full story and X-Rays of the Wellbrook:
https://www.george-smart.co.uk/projects/wellgood_loop/