1918 Navy ADF?

[Larry Dighera]

Could this be the first ADF receiver?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2251366814&indexURL=0&photoDisplayType=2#ebayphotohosting

[Gerald Sylvester]

Larry Dighera wrote:
> Could this be the first ADF receiver?
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2251366814&indexURL=0&photoDisplayType=2#ebayphotohosting

$3500. hehehe. a $120 GPS does more these days. ;-)

Gerald

[Larry Dighera]

On Sun, 27 Jun 2004 00:22:27 GMT, Gerald Sylvester
> wrote:

>Larry Dighera wrote:
>> Could this be the first ADF receiver?
>> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2251366814&indexURL=0&photoDisplayType=2#ebayphotohosting
>
>$3500. hehehe. a $120 GPS does more these days. ;-)

Actually, the seller wants more than $3,900.00 for it, but that's
because of its scarcity, not its functionality.

Frankly, I didn't know that radio direction finding was employed for
aviation use before the '20s. I'd sure like to know more about this
subject.

[Nathan Young]

On Sat, 26 Jun 2004 23:52:25 GMT, Larry Dighera >
wrote:

>Could this be the first ADF receiver?
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2251366814&indexURL=0&photoDisplayType=2#ebayphotohosting

Looks easy to operate :-)

[G.R. Patterson III]

Larry Dighera wrote:
>
> Could this be the first ADF receiver?

No. That receiver could be used to drive a radio compass, which was a (by today's
standard) a primitive homing device. It used a fixed loop antenna. The Radio
Direction Finder was derived from this device later and used a loop which could be
rotated. The ADF was derived from the RDF.

So this could be regarded as the grandfather of the ADF.

George Patterson
None of us is as dumb as all of us.

[G.R. Patterson III]

Larry Dighera wrote:
>
> Frankly, I didn't know that radio direction finding was employed for
> aviation use before the '20s. I'd sure like to know more about this
> subject.

You're correct. This is a radio compass, not an RDF.

George Patterson
None of us is as dumb as all of us.

[Kevin Darling]

Larry Dighera > wrote in message >...
> Frankly, I didn't know that radio direction finding was employed for
> aviation use before the '20s. I'd sure like to know more about this
> subject.

Not ADF, of course, but DF existed from the early 1910s, and was
shortly thereafter installed on some naval vessels.

Apparently by 1914 DF was being tested on winged aircraft. The
British looped a wire from the cockpit out along the top wings, and
back via the lower wings... thus creating a loop antenna on each side
of a biplane. This allowed the pilot to easily home into his base's
radio station. ("Most Probable Position, a History of Air
Navigation")

By the end of WW-I, DF equipment was well along, and the SE950 model
in the eBay ad was designed and built in early 1918 in only two weeks
after it was requested. See:

http://earlyradiohistory.us/1963hw23.htm

The first aircraft to cross the Atlantic (the "NC-4" in 1919) used a
SE950 to figure out it was off course, after its compass jumped its
gimbal on takeoff.

Cheers, Kev

[AES/newspost]

In article >,
(Kevin Darling) wrote:

> Larry Dighera > wrote in message
> >...
> > Frankly, I didn't know that radio direction finding was employed for
> > aviation use before the '20s. I'd sure like to know more about this
> > subject.
>
> Not ADF, of course, but DF existed from the early 1910s, and was
> shortly thereafter installed on some naval vessels.
>
> Apparently by 1914 DF was being tested on winged aircraft. The
> British looped a wire from the cockpit out along the top wings, and
> back via the lower wings... thus creating a loop antenna on each side
> of a biplane. This allowed the pilot to easily home into his base's
> radio station. ("Most Probable Position, a History of Air
> Navigation")

Question: At what point in time did electronic amplification (i.e.,
vacuum tube technology) come into those systems -- or any other military
or commercial systems -- whether at the RF, audio, or any other stages?

My impression is that as of the early 1910s the transmitters would have
been either spark-gap or rotary mechanical in character, with crystal
detectors at the receiving end. When did vacuum tube amplifiers or
oscillators come into regular use in any part of these systems?

[Dave Stadt]

"AES/newspost" > wrote in message
...
> In article >,
> (Kevin Darling) wrote:
>
> > Larry Dighera > wrote in message
> > >...
> > > Frankly, I didn't know that radio direction finding was employed for
> > > aviation use before the '20s. I'd sure like to know more about this
> > > subject.
> >
> > Not ADF, of course, but DF existed from the early 1910s, and was
> > shortly thereafter installed on some naval vessels.
> >
> > Apparently by 1914 DF was being tested on winged aircraft. The
> > British looped a wire from the cockpit out along the top wings, and
> > back via the lower wings... thus creating a loop antenna on each side
> > of a biplane. This allowed the pilot to easily home into his base's
> > radio station. ("Most Probable Position, a History of Air
> > Navigation")
>
> Question: At what point in time did electronic amplification (i.e.,
> vacuum tube technology) come into those systems -- or any other military
> or commercial systems -- whether at the RF, audio, or any other stages?
>
> My impression is that as of the early 1910s the transmitters would have
> been either spark-gap or rotary mechanical in character, with crystal
> detectors at the receiving end. When did vacuum tube amplifiers or
> oscillators come into regular use in any part of these systems?

Around 1913 Deforest sold an audion tube to the general public. Tube
development took off during WWI and they made their way into transmitters
and receivers during the war.

There were an untold number of detectors back then.

Transmitters would have been spark gap, quench gap or arc. The Alexanderson
alternator came out around 1918. There was a huge Alexanderson transmitter
still in operating condition in Sweden up to a couple of years ago. It
still might be in operating condition and put on the air for special
occasions.

[Larry Dighera]

On 27 Jun 2004 13:17:09 -0700, (Kevin Darling)
wrote:

>Larry Dighera > wrote in message >...
>> Frankly, I didn't know that radio direction finding was employed for
>> aviation use before the '20s. I'd sure like to know more about this
>> subject.
>
>Not ADF, of course, but DF existed from the early 1910s, and was
>shortly thereafter installed on some naval vessels.
>
>Apparently by 1914 DF was being tested on winged aircraft. The
>British looped a wire from the cockpit out along the top wings, and
>back via the lower wings... thus creating a loop antenna on each side
>of a biplane. This allowed the pilot to easily home into his base's
>radio station. ("Most Probable Position, a History of Air
>Navigation")
>
>By the end of WW-I, DF equipment was well along, and the SE950 model
>in the eBay ad was designed and built in early 1918 in only two weeks
>after it was requested. See:
>
>http://earlyradiohistory.us/1963hw23.htm
>
>The first aircraft to cross the Atlantic (the "NC-4" in 1919) used a
>SE950 to figure out it was off course, after its compass jumped its
>gimbal on takeoff.
>
>Cheers, Kev

Thank you for your summary and the link to the Development of
Aircraft Radio Equipment article. This well written chronicle of
the initial use of radio equipment in aviation service is what I
wanted.

[Larry Dighera]

On Sun, 27 Jun 2004 22:53:09 GMT, "Dave Stadt" >
wrote:

>
>"AES/newspost" > wrote in message
...
>> In article >,
>> (Kevin Darling) wrote:
>>
>> > Larry Dighera > wrote in message
>> > >...
>> > > Frankly, I didn't know that radio direction finding was employed for
>> > > aviation use before the '20s. I'd sure like to know more about this
>> > > subject.
>> >
>> > Not ADF, of course, but DF existed from the early 1910s, and was
>> > shortly thereafter installed on some naval vessels.
>> >
>> > Apparently by 1914 DF was being tested on winged aircraft. The
>> > British looped a wire from the cockpit out along the top wings, and
>> > back via the lower wings... thus creating a loop antenna on each side
>> > of a biplane. This allowed the pilot to easily home into his base's
>> > radio station. ("Most Probable Position, a History of Air
>> > Navigation")
>>
>> Question: At what point in time did electronic amplification (i.e.,
>> vacuum tube technology) come into those systems -- or any other military
>> or commercial systems -- whether at the RF, audio, or any other stages?
>>
>> My impression is that as of the early 1910s the transmitters would have
>> been either spark-gap or rotary mechanical in character, with crystal
>> detectors at the receiving end. When did vacuum tube amplifiers or
>> oscillators come into regular use in any part of these systems?
>
>Around 1913 Deforest sold an audion tube to the general public.

The first triode vacuum tube, which was a signal amplifier, was
invented in 1906 by Lee DeForest:
http://rds.yahoo.com/S=2766679/K=%22lee+deforest%22+%22first+triode%22/v=2/SID=e/l=WS1/R=2/H=0/*-http://web.engr.oregonstate.edu/~mooreiii

>Tube development took off during WWI and they made their way into transmitters
>and receivers during the war.

Three Western Electric VT-1 triode vacuum tubes (first vacuum tube)
were used in the SE950.

>There were an untold number of detectors back then.
>
>Transmitters would have been spark gap, quench gap or arc. The Alexanderson
>alternator came out around 1918. There was a huge Alexanderson transmitter
>still in operating condition in Sweden up to a couple of years ago. It
>still might be in operating condition and put on the air for special
>occasions.

Though a student of early radio, I was surprised to learn that the
first commercial radio station was put into service before the
invention of the triode vacuum tube:

1902: World's first commercial wireless station is opened on Santa
Catalina Island.
http://www.notfrisco.com/calmem/catalina/chrono.html