[HBR] Believe it or not, I'm Working on the HBR :)

[whitebear1122 at comcast.net]

I know.  Willl wonders never cease?  With the bulk of my major 3 year  radio sell off  in the rear view mirror (sold off 80% of my radios), I'm starting back up on the HBR project. 



After vacillating over the past 3 years between building a 17, 16, 11, 12, and 13, I've decided to build the HBR-13, not 13C but straight 13.  I read about Ted and others efforts with difficulty in getting the IF's to be regenerative.  The conclusion by the experts was that the centering of the raised RF subchassis changed things and  had "something" to do with it but they could never put their finger on the absolute cause.  I have an HBR-16 and all three amplifiers easily go into  oscillation on command, and I also have an HBR-13C that just doesn't go into oscillation.   I'm going to build mine  with the dial offset on the left of the panel like the earlier HBR's. 



I never did find the Miller 1730 1800 Kc IF transformers so I've come up with two options for the transformer coupled first IF amplifier stage .  I found a set of BC-454 1415 Kc IF's plus I'm hoping to take delivery soon of a pair of Hallicrafters 1650 Kc IF's.  So I have the 1610 IF amplifier stage figured out. 



For the 100 Kc IF's, I have two options as well, as I've been able to find 2 1709's and 2 1710's over the past couple of years.  Those 4 transformers will cover the 100 Kc IF chain including the back to back first 100 Kc IF amp stage.  I also have a set of BC-453 85 Kc IF's that I may use.  I've been vacillating the past couple of nights over the 100 Kc IF design, wondering if I should make the 2nd 100 Kc IF using back to back transformers like the first back to back stage.  Ted Crosby talks about it in his Oct 1965 article.  I have enough BC-453 transformers to do the dual back to back IF's but not enough 1710 or 1709.  I would need one more 1710 or 1709 to do it with the Miller parts.  The BC-453 IF's are huge and those back to back IF's take up alof of space.  Hence the vacillating and layout changes .  



I am laying out the mechanical design right now.   I was planning for a 17" chassis, then tried for a 14" chassis.  Wow what a tight fit.  I'm back to the 17".  I've completed two full chassis mechanical layout drawings  for a 14" and a 17" chassis, and darn if last night I decided to try one more.  I'm trying different layouts to optimize placement depending which and how many  1610 Kc IF's and 100 Kc IF's I use, what sized chassis, what size cabinet.  Alot of variables.   



The front panel mechanical drawing is complete enough to start drilling the chassis front.  Just need to finish up the chassis top layout so I can drill, mill, and get building.  



I've got an Eddystone dial that is roughly dimensioned on the front panel layout but I won't drill until I complete the rest of the radio and have it working.  Then I can lay the clear plexiglass dummy  panel up to the chassis and double and triple check the dimensioning.   



So that's where I am at moment.  Wish me luck.     



73, Scott WA9WFA