[HBR] Suggestion for HBR-13 Cabinet

[Mike Hanz]

On 3/17/2011 8:40 AM, Walt Hutchens wrote:
> That 'flight deck' project is amazing, Mike.

Many thanks, Walt - you are really the main culprit responsible for its 
conception back in 1989 after I visited your shack in Arlington.  My 
wife says she would like to meet you someday...but she has a funny look 
in her eye and a glance at the knife drawer whenever she says it...

> One thing you don't appreciate unless you've experienced it is the
> noise level from such equipment. The DC blowers and dynamotors aren't
> that far short of the threshold of pain. The 400 cycle (and up) AC
> adds to the pleasure. At altitude (10,000 feet and up) it's not a
> problem but running this stuff in a ground level ham shack is not
> quite like using a Yaesu.

Absolutely!  It's a niche market, for sure...  Of course, very little of 
the rotary equipment in a larger setup is actually spinning at any given 
moment in time.  It's the rotaries with open housings that create the 
most noise.  The dynos with the closed ends are actually almost silent, 
including the big one for the BC-375.  The ART-13 dyno is a particularly 
persistent irritation when you're speaking, as you well know.  But the 
all time WWII champ is the 800~ rotary inverter for the two old Navy 
transmitters, which has a siren-like shriek quality about it. =-O   
Fortunately, I've hidden a pair of modern Behlman lab inverters behind 
the 'flight deck' to provide 400 and 800~ power, so I don't have to have 
my hearing checked so often any more...heh.

Eh, what's that you say?  Wait a minnit - let me turn up my hearing aid...

> I especially enjoyed the info on obscure jammers.  It hadn't occurred
> to me that one could voice modulate them!

It didn't occur to me at first either, but modulation is modulation, so 
eventually my braincells kept kicking me enough to try it.  The original 
noise tube sources are broadband, so a low pass audio filter in the 
chain with level correction is pretty much all you need.  What you get 
out is of course whatever the technique originally designed in...DSBRC 
was a favorite of the later jammer designs, so that's what you have with 
those particular units.

> However I'm still claiming to be the only ham to communicate using the
> VHF/MF double modulation systems -- across the shack with a home-made
> few milliwatt transmitter to the Navy version of the receiver.

I believe that's still a record, AFAIK.  (Walt is referring to the old 
ZB-*, AN/ARR-1, and ARR-2 homing receivers that guided aircraft back to 
the carriers in WWII.)  I've modulated the calibration oscillator in the 
set's test equipment suite to transmit old time radio broadcasts at a 
few milliwatts, but never tried any live voice - the music sounds about 
as well as can be expected...:-\

73,
Mike