A question for John Bryant

Roy <roy.dyball@...>

Hi John

With using the G8 and PL-380 in the close vicinity of computers and having got the software up and running it is time to get my little radios able to receive a good clean signal free of computer hash. Initially I thought of just winding a couple of turns around the loopstick and bringing the antenna in that way. Sure I would get a nice strong outside signal into my metal frame shed but I would still have all of the noise generated in the shed still being induced by the loopstick. The obvious answer now seems the loopstick has to go, for computer operations.

Now that Scott has explained the correct workings of the Si4734 front end I think an Amidon FT-114A-61 wound to around 250µH to replace the loopstick coil and a 3-5 turn coil wound on the same toroid to bring in the 50 ohm antenna coax. We are very lucky with the Si4734 chip in that it only needs two wires for AM input (no feedback coils) so I feel very confident that this setup will work.

I have read your articles on winding baluns and can see you have much experience on this subject. How would you suggest I wind the Coils on the toroid? Do you think there is any advantage using Litz, or maybe a combination of Litz, enamel for each section. I plan to mount the torrid on the back cover where my broken flap stand is and it should look quite neat with a small plastic dome cover. It will be switchable to allow the loopstick to still work. I would appreciate any comment on the above.  

Cheers Roy.

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