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

[Steve]

Scott

I am following what you are doing closely so that I can learn how to build
one of the HBR's myself...I am not as far along as you since I do not have
the IF figured out yet.   I have the 85Khz ones, they are all the same part
number too...Not sure if that is good or bad...I have some unknown 265Khz IF
transformers that I am trying to characterize with the specturm analyzer and
then modify them for 100Khz.  This is turning out to be more difficult than
I had thought it might be.  I am interested in CW only so want as narrow a
bandpass as I can reasonably get...I am not sure what the correct test
fixture for these might be.  I am using a 22k input resistor and a 100
resistor across the output of the transformer with no coupling caps.  Does
the collective wisdom of the group think this is a correct method???  I have
a nice HP sweep generator and a HP8590 Spectrum Analyzer.  No tracking
generator but I hope this will work this way..

Steve  NU0P


-----Original Message-----
From: hbr-bounces at mailman.qth.net [mailto:hbr-bounces at mailman.qth.net] On
Behalf Of whitebear1122 at comcast.net
Sent: Friday, January 17, 2014 1:02 PM
To: HBR Receiver List
Subject: [HBR] Believe it or not, I'm Working on the HBR :)



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 

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