[CW] another earhart blurb

[George, W5YR]

Most aircraft radios in civilian planes other than "transports" were
equipped to transmit only on 3105 and 6210 Kc (not kiloHertz!) You used 3105
during the day and 6210 at night.

Receivers were generally tunable and covered a fairly wide frequency range,
including the LF four-course nav aids and homing beacons using loop
antennas.

I had a modern-day version of that generation of radio back in 1951-2 in a
Piper Super Cruiser. IT was an RCA radio.The transmitting/receiving antenna
was a fixed wire with tuning in the rig for the two frequencies. A large
internal loop allowed highly accurate homing on range stations, beacons,
even BC stations. I once homed in on a BC station in St. Louis and passed
directly over the tower!

The ARC-5 is, of course, a creation from WW2 but it embodied the technology
of the late 30's no doubt.

73/72, George
Amateur Radio W5YR -  the Yellow Rose of Texas
Fairview, TX 30 mi NE of Dallas in Collin county EM13QE
"Starting the 58th year and it just keeps getting better!"
w5yr@att.net





----- Original Message ----- 
From: "rb" <rbig@bellsouth.net>
To: <cw@mailman.qth.net>
Sent: Tuesday, November 11, 2003 3:48 PM
Subject: [CW] another earhart blurb


> Think we should give a bit more credit to American aircraft radio
engineers
> of the mid to late 1930s.
> The ARC-5 transmitters are of that era, and there is no way they could be
> tuned up on second and third harmonics without extensive electrical and
> mechanical modifications.
> The crystal controlled transmitters of the day used in civil aircraft were
> channelised and fixed tuned with usually only antenna loading adjustable
> within the aircraft.
> They were set up before flight and operated by the pilot via a control
box.
> As you say, one can visualise scenarios whereby the radio was damaged in a
> forced landing and somehow came to put out signals on a harmonic but this
is
> stretching the bounds of plausibility.
> I am puzzled by hypotheses about running an engine to charge the batteries
> after a forced or crash landing.
> One would assume that the aircraft came down with the batteries fully
> charged.
> Assuming the batteries survived the landing, then there would have been
> capacity to run the radios for some time with full power from the tx.
> There were plenty of ships and aircraft around listening on known channels
> and it seems very unlikely that Earhart would not have been heard loud and
> clear if the equipment was intact.
> As I recall the note in Old Timer's Bulletin suggested that Earhart may
have
> been confused by procedural directions from the US Navy that used both
> frequencies and wavelengths with the consequence that she neither
> transmitted or listened on the correct frequencies.
> Earhart had learned to fly during the barnstorming era when flight
training
> was sloppy by modern standards.
> She never had experience as a pilot under discipline in either the
services
> or in scheduled airline operation.
> In these areas pilots learn that standardised procedures and drills are
> everything.
> Taking into account the accumulated fatigue, questions about Earhart's
state
> of health, (amongst other things, it has been suggested she might have
been
> pregnant at the time) and the lack of drills and rehearsals of radio
> procedure before she left Lae it is likely that pilot  error was a factor.
> If Noonan had been allocated the radio operating tasks things might have
> gone better, but this was impossible due to the layout of the Electra as
> modified. The actual navigation tasks were routine, no problem for Noonan,
> but pushing the limits of precision on a long flight.
> If the radio procedures had worked as planned then there would have been
no
> problems: the US Navy ships would have got a fix on them and they would
have
> been able to RDF on the homing beacon set up for them or on MF
transmissions
> from ships.  With good RT communications they would have been talked into
> their destination with the greatest of ease.
> Sad.
>
>
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