| Author |
Message |
Jeremy Parker
Guest
|
 Posted:
Wed Nov 23, 2005 5:08 pm Post subject:
Re: Wanted: Quality Sextant |
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"Gary" <plumperNOSPAM@shaw.ca> wrote
| Quote: | Decca might still be in use in Europe. It is completely different
from
Loran A or C. Omega is the other old radio nav aid. I have used
them
all. Loran C was easiest followed by Decca and I used them
asrecently
as 10 years ago. Loran A was phased out in the 80s and Omega I'm
not
sure about. Omega was good way out off shore while the others had
range
limitations.
|
Omega. Ah. Isn't that the one which used a low frequency, fairly
close to the long-wave broadcast band used in Europe? Thus you could
navigate with an ordinary portable radio, pointing it at each
transmitter in turn, to get bearings. Still, I suppose you can do
that with real broadcast stations, too.
In the lifeboat scenario, all you want to do, really, is to find the
nearest island or continent, I suppose. You wouldn't be picky about
details. I recall being told about some group of hippies, back in
the 1960s, who built a boat to sail from California to Hawaii. They
proposed to learn celestial navigation en route, but somehow the
textbook got dropped overboard fairly early on. That didn't matter
though. They were able to get to Hawaii with no problem. Their
method was to follow the contrails of the airliners in the sky.
Shackleton, Bligh, and Tevake the Navigator, eat your hearts out.
Jeremy Parker |
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Terry Spragg
Guest
|
| Posted:
Thu Nov 24, 2005 12:28 am Post subject:
Re: Wanted: Quality Sextant |
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Jeremy Parker wrote:
| Quote: | "Gary" <plumperNOSPAM@shaw.ca> wrote
Decca might still be in use in Europe. It is completely different
from
Loran A or C. Omega is the other old radio nav aid. I have used
them
all. Loran C was easiest followed by Decca and I used them
asrecently
as 10 years ago. Loran A was phased out in the 80s and Omega I'm
not
sure about. Omega was good way out off shore while the others had
range
limitations.
Omega. Ah. Isn't that the one which used a low frequency, fairly
close to the long-wave broadcast band used in Europe? Thus you could
navigate with an ordinary portable radio, pointing it at each
transmitter in turn, to get bearings. Still, I suppose you can do
that with real broadcast stations, too.
In the lifeboat scenario, all you want to do, really, is to find the
nearest island or continent, I suppose. You wouldn't be picky about
details. I recall being told about some group of hippies, back in
the 1960s, who built a boat to sail from California to Hawaii. They
proposed to learn celestial navigation en route, but somehow the
textbook got dropped overboard fairly early on. That didn't matter
though. They were able to get to Hawaii with no problem. Their
method was to follow the contrails of the airliners in the sky.
Shackleton, Bligh, and Tevake the Navigator, eat your hearts out.
Jeremy Parker
|
That is reminiscent of the original longitude solution prescribing
lighthouse ships anchored every 20 miles along the equator. How was
that supposed to work, even if it was practicable?
Terry K |
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rhys
Guest
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| Posted:
Fri Nov 25, 2005 5:00 pm Post subject:
Re: Wanted: Quality Sextant |
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On Wed, 23 Nov 2005 07:25:31 -0000, "David Lee"
<davidlee_malvern@dont.use.this.bit.hotmail.com> wrote:
| Quote: | That was "Oboe", used for precise indication of bombing release position -
it was only used for during final approach of a bombing run. The technique
was based on secondary radar and the aircraft carried two transponders that
responded to signals from two ground stations in England codenamed CAT and
MOUSE. The aircraft (usually a pathfinder Mosquito) flew a circular course
at constant distance from CAT, which automatically broadcast Morse code dots
if the range was too short and dashes if too long. When the aircraft was
exactly on course (in practice within range plus or minus 17 yards) these
merged and the Mosquito pilot heard a continuous tone.
MOUSE monitored the range and velocity of the aircraft (accuracy 17yds /
0.5mph) and its computer (THE MICESTRO!) continuously updated the solution
for the release point based on this and met data. MOUSE then broadcast a
series of Morse code signals counting down to the target, culminating with
the release signal - five dots and a dash.
The aircraft had to be under Oboe control for at least 10 minutes and so the
maximum number of runs controllable by a single pair of CAT and MOUSE
stations was only six per hour. However by controlling pathfinder
Mosquitos, dropping marker flares, the system permitted bombing with
unprecedented and devastating precision.
Oboe...you, sir, are correct. My ability to recall trivia I ingested |
35 years ago is fading. I recall also that this, while a clever
solution that made the British night bombing near-surgical when
everything worked, was disliked by some pilots due to the very
predictable courses they had to fly which was easily observed by the
German plotters.
As the Mosquitos were about as fast as opposing fighters, and as they
had better airborne radar than the Germans, they could avoid trouble.
But if the ground fire figured out the pattern they were flying over
the target, it could get very unpleasant very quickly.
It's a sad fact that wartime ingenuity provided some very useful
advances for boating in the post-war period that were helpful for
decades until GPS trumped all.
R. |
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