[Boatanchors] B&W Tank Coils

Chris Kepus ckepus at comcast.net
Sun Dec 30 14:21:12 EST 2012


If my grey cells were more cooperative I could remember some specific examples of what you have suggested.  Perhaps some others could provide some memory assistance and provide real life examples of the amps where a toroid is used for 160M. If more inductance is needed for the 852 for low(er) current, high voltage tubes to preserve Q, a suggestion on adding inductance for 80M using an 852 would likely be appreciated by Wilson.  

However, in an off list reply, Wilson said he received a response that the 852 could be resonated on 80 (75?). "Subsequently, someone sent data showing the big coil is 7+uH and can be tuned to 80 with something like 270pF. So to use it one uses big tubes drawing a lot of current, to keep the plate Z under 3K Ohms."

Since my 4-1000 "Junker Amp" project is getting closer to the construction phase, I went to another reference that was returned when I searched for a picture of the 852. 

The same author that provided the web pictures of the 852 I first found, had posted additional pictures on another web site showing his restoration of the amp as well as side by side views of a 852 and 850. http://myplace.frontier.com/~k7ncg/3-1000%20Project.htm 

Besides enjoying looking at all of his work, the pics of the B&W 852 and B&W 850 all restored and prettied up are worth the price of admission.

73 and HNY to all,

-----Original Message-----
From: boatanchors-bounces at puck.nether.net [mailto:boatanchors-bounces at puck.nether.net] On Behalf Of qrv at kd4e.com
Sent: Sunday, December 30, 2012 9:37 AM
Subject: Re: [Boatanchors] B&W Tank Coils


	Perhaps less broadband or efficient but might he add some inductance using a toroid-wound coil?

	I think I have seen that where Hams have added 160m to amps.



> Wilson, check out the picture at http://www.k7ncg.com/Old%20Amp.htm
> .
> Scroll down about 11 pictures.  Does yours have all the parts and 
> coils shown in this side view?  It sounds like you are missing the 
> flat wound coil portion.
> 73 and Happy New Year, Chris W7JPG
> Been looking for one for a while. Found model 852, high power one, 
> with coil all of large (3/8”) tubing. Calculations show it can’t do 
> 80m, which seems odd. Does anyone have a datasheet or instructions for 
> the B&W 852? Thanks, Wilson W4BOH


Thanks! & 73, KD4E.com
David Colburn nevils-station.com
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