[HBR] HBR form factor - "mods"

[Walt Hutchens]

Mike Hanz quoted Bill C.:
>> I would like to change the form factor to something like the ARC5
>> command transmitters/receivers. I think HBR would be a bit larger
>> than those BUT that general shape would better fit into a smaller
>> radio shack I think. The plug-in coils for band changing do not
>> have to be arranged near a long band switch so that part of the
>> design really lends itself to changing the form. The multi-section
>> tuning cap running from front to back also lends itself to changing
>> the form. Obviously one of those wide tuning dials is not going to
>> fit. My idea of 'mods' is a rearrangement and redistribution of the
>> circuit 'modules' along with a round dial mechanism.
>>
>> Have I overlooked something critical?

And commented:
> I'm sure you have received a lot of replies by now, Bill, but just
> for an added data point, just about all the HF aircraft radios
> designed after 1940 or so took the same approach, for the same
> reason you mention...efficient use of the space available. One
> interesting exercise might be to look at the redesign of the
> Hallicrafters SX-28A from its wide front panel civilian
> configuration to the repackaged version in the R-45/ARR-7
> (http://aafradio.org/countermeasures/ARR-7.jpg

There was a later version of the ARR-7, designated R-???/ARR-7A that
used miniature tubes and has some other refinements.

I've often thought this sort of repackaging exercise would be
interesting, as well as potentially useful for conserving the width of
an operating table.  There are still many items of WW-II and later
electronic junk floating around in the ATR package and with new skin
on the chassis and panel, these would be ideal as a starting point.

Plug in coils become more difficult in such a package because of the
requirement for a hinged lid and shielding/space between coils.
However this doesn't seem an insurmountable problem.

One issue with small front panels is that they are SMALL. By the time
you plop a readable dial on them and find room for even a miniature
S-meter, the number of controls found on a typical receiver (let alone
an HBR-type design) borders on impractical unless you use miniature
pots and switches. The better approach, most likely, is to reduce the
number of controls.

The rest of a typical ham receiver lends itself fairly well to narrow
panel construction. The tuning cap can be centered with the shaft
perpendicular to the panel; coils can be on one side with the
corresponding tubes on the other.  Then the IF's string out from there
backward to the detectors, the power supply is behind the detectors
and the AF and AGC sections come back up the other side of the chassis
toward the panel.

I think the ATR panel is 11-1/4" wide or something like that?

Actually, the project I've considered is the 'command sets' as I think
they should have been done to start with: A tunable transceiver
covering (say) 80-40-20M in an ATR package. I have the box and chassis
set aside but I don't know when I'll ever get to this project.

First things first. I recently re-kit-ed the sort-of-HBR type design I
started a couple of years ago, re-did the chassis (finally got the
layout right!) and started rebuilding.

19JN8 RF-cal. osc.
19J6  mixer
12BZ6 LO
19JN8 1st IF-AGC diode
19JN8 2nd IF-AGC plate detector
19JN8 1st audio-audio plate detector
12AU7 BFO-bias rectifier
117N7 2nd Audio-B+ rectifier

Series filaments and silicon-free. I have a few days now (probably)
before the next crisis, and we are semi-snowed in, so maybe ...

Walt
KJ4KV