[Milsurplus] [Boatanchors] Hallicrafters and A-Bombs (Hello, NSA and HSA!)

[Mike Hanz]

Possibly, though most of the weapon peripherals were developed by LASL for specific purposes because of the magnitude of the forces involved.  The canister instruments finally decided upon were specially designed and built condenser microphones.  I'm not near my documents at the moment, but I think there was an air bleed to the microphone chamber that allowed the microphone to ignore slow changes in pressure, such as the altitude change during the drop, while maintaining calibrated accuracy for the over pressure pulse.

> On Mar 30, 2014, at 12:59 PM, "J. Forster" <jfor at quikus.com> wrote:
> 
> I wonder if those pressure probes might have been ART-4 derived, because
> that's exactly what the ART-4 does...  it monitors pressure pulses to
> determine target scoring for gunnery practice.
> 
> They transmit on 55.5 and 56.75 MHz.
> 
> -John
> 
> =============
> 
> 
> 
>> Nope.  The radar altimeters were in the 400mHz range.
>> 
>> Three AN/ARR-5 receivers were used in whatever Silverplate airplane was
>> designated the instrumentation aircraft for each mission, with the task of
>> dropping three parachuted pressure instruments to monitored the pressure
>> wave created by the weapon.  With that data and knowing the altitudes and
>> positions of the three canisters, it was possible to calculate the size of
>> the over pressure pulse and thus the yield of the weapon.  The
>> instrumentation aircraft preceded the weapon carrier, IIRC, to allow the
>> canisters time to descend a bit from the high altitude the aircraft were
>> flying. The canister frequencies were clustered around 50MHz or
>> so...somewhere back home I have the specific freqs involved from a LASL
>> report years after the fact.  So, the S-36 was probably in the rack to
>> permit calibration of the pressure sensors for testing.
>> 
>> 73,
>> - Mike  KC4TOS
>> 
>> 
>> 
>>> On Mar 30, 2014, at 11:01 AM, "David Stinson" <arc5 at ix.netcom.com>
>>> wrote:
>>> 
>>> I guess it would work better with the link:
>>> 
>>> http://www.alternatewars.com/Bomb_Loading/Bomb_Guide.htm
>>> 
>>> The receiver is an S-36, so likely to listen to the altimeter
>>> transmittters.
>>> _____________________________________________________________