[HBR] Another HBR Project

[hbr@mailman.qth.net]

Wandering around the HBR site in the last week I got the urge to try 
something more like the traditional design.   Yeah, I know I should 
finish up the HBR2K project, but the summer has been a mess and I 
really need a break.   The set works well -- it's on daily duty in the 
kitchen -- but needs further testing and probably further tweaking of 
the 1st mixer and RF amp.

So for a break, well, looking at the various diagrams I thought "what 
about a quicky"?   Rather than ask the logical question ("Are you 
crazy?")  I cut to the chase:  1.  Do I have all the parts?   The answer 
-- with some compromises -- turned out to be 'yes.'   And,  2. Could I 
do this in a week flat?   The answer to that required less thought than 
you might expect: My wonderful wife Sharyn said "No"!   I'd need to 
be able to do 12-16 hour days for a week and (basically) that's not 
gonna happen with the life we have.

But ... maybe two weeks?   Anyhow, I'm going to try ... might make 
it if nothing much else craps out household-wise and the grass starts 
to slow down for the summer.   What I've worked out is a 10-tube 
design on a 10" x 12" x 3" chassis, using a command set tuning cap 
and dial drive.   And -- for the heck of it -- the command set plug in 
coil set in place of independent coils.      I think I've figured out how 
to plug the coils in through the front panel.  (Sort of a very poor man's 
HRO.)  Replacing the antenna and RF coils with toroids ought to give 
good enough Q's and locating the coils under the chassis should be 
good for stability.  Command set IFTs as well -- 1415 kcs retuned to 
1610 and 85 kcs. For the time being I'll use just one IF stage but 
there'll be room for another if needed.   I once converted a command 
set to double conversion by replacing the 1st IF stage with a mixer; 
as I recall that had enough gain, so why not?

Lots of issues, but what's a project for, if not a learning experience?   

So far I have a chassis sketch that looks okay -- gee, I never had so 
much space for just 10 tubes.   Tomorrow, knock the holes in the 
chassis.   We'll see how it goes.   

Walt Hutchens
KJ4KV