[ARC5] Pre-ARC-5 rigs.

Mon Aug 4 19:55:34 EDT 2014

> Other sources allege that perhaps AE had obtained a Bendix RA-1 receiver
via the US Navy.  The Bendix receiver
> would have either supplanted or replaced the WE unit; the Bendix was a
much more capable receiver.  This would have
> solved the question of her being able to receive at 1300 kc.

That tallies with my recollection that she carried a military radio, but I
was unable to remember what type.

The RA-1B has direct frequency readout on the dial, if I'm not mistaken, so
she should have been capable of setting to correct frequency, unless she
made an error with the bandswitch. Surely she had enough gumption to be
aware that that might be a problem after hearing no response from the
"Itasca"?

73 de Neil ZL1ANM

On Tue, Aug 5, 2014 at 6:03 AM, Mike Everette via ARC5 <arc5 at mailman.qth.net
> wrote:

> I did a lot of research for TIGHAR (The International Group for Historic
> Aircraft Recovery) about 12-14 years ago re Earhart's communications gear.
>
> TIGHAR maintains that AE carried a Western Electric 13-series transmitter,
> and a Western Electric receiver the nomenclature for which escapes me at
> the moment.
>
> The receiver was pretty crude.  It had no RF stage, and a 96 kc IF, having
> been design-optimized for reception of radio range signals (150-400 kc or
> thereabouts) and the AM BC band (up to 1500 kc in 1937).  It also tuned
> 1.5-10 mc in 2 bands.  The receiver had been modified by WE to "fudge" the
> AM BC band down so the 500 kc distress frequency could be covered, which
> lowered the top end of the BC band down as well -- maybe to something like
> 1200 kc (the tuning cap was straight-line-wavelength, just like most period
> home BC sets).
>
> This modification of tuning range raised some real interesting questions,
> among them being how AE could have supposedly received transmissions from
> BC station KGMB in Honolulu after she went down, which TIGHAR theorizes was
> on Gardner Island (Nikumaroro) in the Phoenix Group.
>
> Other sources allege that perhaps AE had obtained a Bendix RA-1 receiver
> via the US Navy.  The Bendix receiver would have either supplanted or
> replaced the WE unit; the Bendix was a much more capable receiver.  This
> would have solved the question of her being able to receive at 1300 kc.
>
> AE's transmitter was a 3-frequency, crystal controlled rig originally
> designed for 2500-6500 kc coverage.  It was tuned for the then-standard
> airways communications frequencies of 3105 and 6210 kc, and had been
> factory-modified by WE to also include 500 kc.
>
> Mike Hanz's aafradio dot org web site has information on the transmitter.
>  The modified unit, which also included CW capability -- not present in the
> original design -- was called the 13CB.  A schematic is on Mike's site.
>
> The WE gear was cumbersome to operate.  The switchology was involved, and
> tuning the receiver back and forth from nav to comm frequencies would
> confuse a lot of us -- let alone AE, who was a radio-doofus.
>
> AE could never have coped with an SCR-183/283; the coil changing alone
> would have overwhelmed her.  Besides, the power output would have been far
> too low.  (Her WE 13 ran at 100 watts input.)
>
> Photo evidence rather clearly nails down the fact that the WE 13-series
> transmitter was aboard; the receiver is pretty much accepted (by TIGHAR) to
> have been the companion WE (Model 20...?) but I myself am still open to her
> having carried a Bendix.
>
> This is a gross oversimplification, indeed a surface-scratching of what is
> known about AE's comms; but suffice it to say, I would definitely rule out
> an SCR-183 having been aboard.
>
> By the way, the radio operator she originally planned to take along, Harry
> Manning,"bailed" on the project after AE cracked up on takeoff from Hawaii
> on her first attempt at a round-the-world flight.  Reportedly, Manning
> swore he would "never fly with that woman again!"  They were darn lucky
> that the overloaded, gas-filled plane didn't turn into a giant fireball
> when the landing gear collapsed.
>
> AE's navigator, Fred Noonan, had been employed by Pan Americal Airways;
> and had supposedly qualified as a radio operator for PAA as well -- but the
> evidence strongly suggests to me that Noonan must have had someone else
> take the Second Class Radiotelegraph Operator exam for him (!!!!!).  (This
> license was required for aircraft radio operators.)  That would have been a
> lot easier to do in 1937 than in modern times.
>
> Neither Noonan nor Earhart had any CW proficiency.  In fact, AE had left
> her telegraph key behind as a "weight saving" measure.
>
> If there is further interest in this topic, I'll try to answer questions
> to my best ability.
>
> 73
>
> Mike
> WA4DLF
> --------------------------------------------
> On Sun, 8/3/14, WA5CAB--- via ARC5 <arc5 at mailman.qth.net> wrote:
>
>  Subject: Re: [ARC5] Pre-ARC-5 rigs.
>  To: arc5 at mailman.qth.net
>  Date: Sunday, August 3, 2014, 7:32 PM
>
>  Neil,
>
>  I haven't really been interested enough in the Earhart
>  fiasco to remember
>  most of what I've read about it.  But I didn't think
>  there was any question
>  about what radios she carried other than if I recall
>  correctly some
>  speculation that she might have dumped some of it.  But
>  in any case, the SCR-183 and
>  SCR-283 were at the time current US military sets.  And
>  not in plentiful
>  supply.  Although I won't go so far as to say that no
>  one could or would have
>  broken the rules, it's highly unlikely that she could have
>  gotten her hands
>  on whichever of the two would have worked in her airplane..
>
>  Robert Downs - Houston
>  wa5cab dot com (Web Store)
>  MVPA 9480
>
>  In a message dated 08/03/2014 18:09:16 PM Central Daylight
>  Time,
>  neilb0627 at gmail.com
>  writes:
>  > Yes I see that. OK, I was wrong about the origin of the
>  SCR-183/283. I
>  > had
>  > assumed that because a coil set in my possession was
>  made by W.E. that
>  > that
>  > company was the original designer/builder. I was wrong,
>  but that doesn't
>  > necessarily negate my question about whether Earhart
>  carried a W.E.
>  > SCR-183/283 set, does it? Or does it?
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