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THE AM BULLETIN BOARD => Military Amateur Radio Section => Topic started by: WC4D on July 24, 2019, 07:46:47 PM

Title: BC 610 model I question
Post by: WC4D on July 24, 2019, 07:46:47 PM
I have a BC 610 I model and I was wondering if anyone had ever used a B&W 850 tank coil to replace the plug in coils that the 610 uses. I have the tank coil and I've been told you can't switch them out and use the B&W coil as a replacement. I was just wondering if anyone had ever tried and did it and if you did just what does it take to make that change? I have a full set of plug in coils but I just think it would be nice to have one tank coil in there and not have to do all the switching.. I'm going to used a VFO instead of the tuning units also .. I just wonder if my thought would work or not .. any ideas would be wonderful..

73 Don WC4D

Title: Re: BC 610 model I question
Post by: WD5JKO on July 24, 2019, 08:16:29 PM

   Some things to consider are neutralization, stage gain, and stability. As I recall, the 610 uses plate side neutralization with a split stator tuning capacitor, and a push pull plug in plate coil. Going to a 850 means essentially a pi-net output. The need to neutralize still exists. Going to grid side neutralization is a possibility, but that means lots of modifications, and debugging.

   You might get by without neutralization if you go to a Tetrode final, but then the stage gain goes way up, and stability will be a big issue. The addition of a screen supply will be an additional task.

    If you have lots of parts, lots of time, and have a good RF background, then why not do some experimenting? My bet, even if you move forward, at some point it will go back to stock, or nearly so.


Title: Re: BC 610 model I question
Post by: WC4D on July 24, 2019, 08:25:35 PM
Well Jim you told me just what I had heard already in so many words but you made it quite clear and it's all about the neutralization and that's what I heard I would have to overcome. I sure don't have any background in RF so I guess I'll keep it stock and run it like it should be run. I have a great looking rig and I shouldn't even think of doing anything to it. I'll send a couple of was just a big hope I guess and I'll have to find me a good chicken stick to do my dirty work.. Thank you again .. I also thought about using a Johnson Ranger to drive it with but I can't find any information on how to do that either .. so stock it will stay .. 73 and thank you for responding ..
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