wrote:
From: on Dec 18, 3:57 pm

wrote:
Dave Heil wrote:
wrote:
From: Dee Flint on Dec 15, 3:21 pm
"Bill Sohl" wrote in message

How much power was used by the Army?

The transmitter used was a modified SCR-271 radar unit. It produced
3000 W on 111.5 Mc. (that's what the Signal Corps called them
back then). Pair of 6C21 triodes in the output - they look similar to
1000Ts.

3000 W output with those tubes at that frequency means about 5000 W
input.
The amateur power limit back then was 1000 W input.

The USN put it to use in communications first, simplex only
with, I think, RTTY. I'll have to find the excellent USN
paper "From The Sea To The Stars" history somewhere on an
archive CD here. Has the history of the USN involvement
in space and communications thereto, from an official USN
website.

All anyone has to do is google that title and the website's URL
will come right up.

Project Diana demonstrated EME radar echoes in 1946.

Amateurs demonstrated radar echoes in 1953.

The Navy first demonstrated EME *communications* in January
1960 (RTTY, Washington DC to Hawaii).

Amateurs demonstrated 2-way EME communications in July 1960.
(Morse Code, 1296 MHz, California to New England)

There's a lot more info at:

http://www.campevans.com/diana.html

is nostalgic over experiments done 59 years ago.

He wasn't there but he was there.

I'm not "nostalgic", Len. Just passing on some information.

Am I not supposed to post urls here?

btw, it was a moon RADAR experiment, not a communications system.

thinks "communications systems" arrive full-blown,
fully-proven? :-)

It took the US Govt. 14 years to go from the EME radar experiments
of 1946 to a working EME communication system of 1960.

Project Diana was an EXPERIMENT to test whether or not the
moon could be used as a radio wave reflector.

Was it?

Or was it an experiment to prove that VHF radio waves could penetrate
the
atmosphere from the earth? (It was already known that radio waves could
do so in the opposite direction, from radio astronomy experiments
before
WW2).

Or was it a gee-whiz sort of stunt to be the first to do something and
try to impress people?

Or maybe some of all of the above?

It was and
what followed were more experiments by many to determine
what the frequency ranges were, the reflection characteristics.

Was there any doubt?

There wasn't any need to "radar" the moon. The moon's orbit
has been accurately known for years, if not centuries. We
can all make certain of where it is. No radar needed for that.

Yet it was indeed a radar experiment.

Those Diana folks had a some hams involved, though - all code tested at
at least 13 wpm:

Conditionals or FCC tested?

Doesn't say. Probably FCC tested.

Uh huh, like Coles, Evans, and Squier laboratories was
busy, busy on ham radio research in 1946? :-)

The amateurs named were all long-time-licensed hams.

In reality, the 1945-1950 time was one of transition from
a world war effort to peacetime and lots of the movers
and shakers in technology-intense war efforts were out to
carve new niches for themselves and their groups.

Ah - so it was partly a form of radiosport for bragging rights, eh?

Good PR
was the word of the day. A "moon bounce" thing was hot PR
at the time, attracted attention from the budget-keepers
in Congress and the Pentagon.

IOW, a gee-whiz sort of stunt to be the first to do something and try
to impress people.

They used power levels 9 dB above those permitted to amateurs at the
time, and
an antenna that was quite beyond "backyard construction". They had lots
of resources.

A fantastic use of post-war resources.

That "111 Megacycle" radar was already surplus before WW2 ended.
Not a problem. :-)

Typical ham radio swords-into-plowshares ingenuity. Why build a new
system
if an old one can be converted?

Anyone riding a bus to Red Bank from Fort Monmouth could look
out and see lots and lots of "junk" at two of the labs along
the highway in 1952, just 6 years after the Diana success. All
sorts of "bedspring" antenna structures were sitting in the
vehicle parking areas.

Looking isn't doing, Len.

When it comes to amateur radio, you're a looker, not a doer.

Lt. Col. DeWitt, W4ERI, was the driving force behind the whole idea,
which he first began working on in 1940.

What idea? To bounce a signal off of the moon for no communications
purpose?

Yes.

In 1940 that ancient Project Diana radar set (the
original, not the kludge version used IN Diana) was
still undergoing operational testing. Even then it was
a late-comer using rather conventional vacuum tubes in the
usual ring-oscillator circuit...the style of transmitter
used by the Brits for radar along the channel.

The British used it effectively. They had relatively crude equipment
but skilled operators and an effective communications network.

Without their radar capabilities the Battle of Britain may have turned
out
differently.

The Brits would come up with the magnetron to make microwave
radars the future practical success.

The reentrant cavity magnetron, actually.

We would incorporate
those in all the later radars at S, C, and X bands during
WW2. The "star" of Army radar was the semi-trailer size
SCR-584 gun-laying radar set which was definitely well above
VHF in frequency range.

The "star"?

How about the airborne radars? Air-defense radars (some so well
developed they were
built into submarine periscopes)? Radio altimeters?

Those were far from "surplus" in
1946. Monmouth had a couple for radar school practice in
1952. :-)

None of which had the power or antennas to do EME anyway.

The concept of reflection of radio waves was well known in
basic radio physics in the 1940s. What was lacking was
some definite information on the characteristics of
radio wave reflection. Nobody had any CONFIRMED idea of
the reflectivity of the lunar surface in the 1940s.

So they built a radar set to do the job.

... During WWII, the Signal Corps used the ARRL
Handbook, Leonard. I'll bet that chafes you to no end.

I really don't think so, having known a lot of USA, USN,
and Air Corps vets who trained during WW2. Some of them
said they used a USN basic book. Nobody mentioned
any "ARRL books." shrug

Yet the books were used. A special "Defense Edition" ARRL handbook
was printed and used by various military branches.

A 2-hour lab class one afternoon had us examine a bunch
of "basic hardware" of radio. One item was a two-tube
MOPA style HF transmitter. That MIGHT have been made
from a ham design although it didn't tune into ham bands
that existed then (instructor told us so, monitored on
an old Hammarlund receiver). We didn't take notes. In
fact, written notes were discouraged. Not for "secrecy,"
but for the need to have it in the head, much more useful
in the field which didn't allow for notebooks or stacks
of magazines for reference which could get rather wet.

In my opinion and experience, that's a poor method of training.

The act of creating a notebook means the student must mentally
process the information and write it in his/her own words. In other
words the student must take an active, rather than passive, role in
the process. Of course the notebooks cannot be depended on
during testing, but that is not their purpose.

Note that in other training systems, such as qualifying in WW2
submarines, the creation of a notebook with all required information
is an essential part.