WWII Direction Finder Fix
 

Hello All:

I believe there was a posting here or maybe even in QST that talked
about problems with Radio Direction Finders in aircraft and ships before
WWII time frame. And the fix to repair them so that the Radio Direction
Finders (RDF) did not point 180 degree's the wrong direction.

I am researching information on the WWII Aviation Rescue Boats, (AVR's)
83 and 104 Ft long, Boats used by the US Army during WWII.

I spent 5 years on a 104 AVR Boat, converted into a Commercial Fishing
Boat for Albacore Tuna from 1966 to 1970 as a teen ager.

Any information would be greatly appreciated. Thanks.

Here's a link that shows some of the AVR Boats and spec's.
http://www.warboats.org/crashboat.htm

Jay

WWII Direction Finder Fix
 

On Tue, 28 Oct 2008 08:18:33 -0700, Jay in the Mojave
wrote:

I believe there was a posting here or maybe even in QST that talked
about problems with Radio Direction Finders in aircraft and ships before
WWII time frame. And the fix to repair them so that the Radio Direction
Finders (RDF) did not point 180 degree's the wrong direction.

Which one?
http://www.angelfire.com/space/proto57/rdf.html

Search Google for "sense antenna". This is a 2nd antenna that is used
in conjunction with a loop or Adcock type antenna to skew the pattern
on one direction, thus eliminating the 180 degree ambiguity.
http://books.google.com/books?id=RfzF2-fHJ6MC&pg=PA237&lpg=PA237&dq=df+sense+antenna&sour ce=web&ots=OrVQdNKmQ-&sig=lF5RRtEjOoyQ22OPvMEFx3Ljrzg&hl=en&sa=X&oi=boo k_result&resnum=3&ct=result
http://books.google.com/books?id=f3asJreno0YC&pg=PA446&lpg=PA446&dq=rdf+lo op+sense+antenna&source=bl&ots=068u54gGNR&sig=3R4X kY8aRiOWMv_cWhCRU94s0JQ&hl=en&sa=X&oi=book_result& resnum=1&ct=result#PPA447,M1

Incidentally, much of the pre-WWII DF work was done from fixed
direction finding stations. A pilot would request location info via
HF radio. Several ground stations would do their best to deliver a
bearing using various types of antennas, with which the pilot would
use to calculate an intersecting position. Gross and inefficient
would be a nice term.

Somewhat later, the "homer" was introduced. This was two wing mounted
forward facing directional antennas. The receiver would rapidly
switch between the two antennas. When the signal level from both
antennas was identical, the transmitter direction was dead ahead. This
worked fairly well, but did create problems for airline passengers as
the pilot flew donuts trying to get a brearing.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

WWII Direction Finder Fix
 

Jeff wrote:
"Somewhat later, the "homer" was introduced."

The last topic in Terman`s 1955 opus is "Radio Direction Finding". On
page 1048 Terman writes: "This behavior (simulated sense antenna) causes
a signal to be delivered to the receiver even though the loop ts in the
position for zero response;"

I have a friend, N5CPA, who was a B-24 bomber pilot flying out of Italy
to bomb Austria and Germany as WW-2 was ending. They had a direction
finding station in North Africa to advise them of their positions when
needed. Problem was, Germans often answered first with wrong location
and direction in impeccable American English so Americans might exhaust
their fuel.

Walter Maxwell worked for the FCC at war`s end in Hawaii and equipped
himself with an Adcock antenna so he could advise lost American aviators
of their positions in the Pacific. I think Walter has published his
story in a radio magazine.

Best regards, Richard Harrison, KB5WZI

WWII Direction Finder Fix
 

On Wed, 29 Oct 2008 18:34:03 -0500, (Richard
Harrison) wrote:

Jeff wrote:
"Somewhat later, the "homer" was introduced."

The last topic in Terman`s 1955 opus is "Radio Direction Finding". On
page 1048 Terman writes: "This behavior (simulated sense antenna) causes
a signal to be delivered to the receiver even though the loop ts in the
position for zero response;"

A homer is quite different. Dumb story follows.

Once upon a time, the government decided that small business needed to
have some of the smaller military contracts directed in their
direction. No altruism was involved as the military was just trying
to cut costs.

Intech Inc was in the marine radio business and decided to bid on a
USCG contract to design and build a homer. The chief engineer handled
the negotiations and I only found out after we had underbid everyone
else by about 50%. Oops. There was just one problem. Nobody knew
what a homer was or how it worked.

After some very strange ideas and misconception, I removed a dusty
copy of Radio Engineering Handbook, 3rd edition, by Henney. This is
the 1941 edition, but much of the data is from the first edition in
1933 thanks to war time censorship. Pg 613 has a schematic of a homer
antenna and receiver system. I drag this to management who initially
declares that the USCG couldn't possibly want something that simple.
It took a while, but I eventually based the design on the ancient
design from the book. It eventually became the AN-SRD/21 homer.

I have a friend, N5CPA, who was a B-24 bomber pilot flying out of Italy
to bomb Austria and Germany as WW-2 was ending. They had a direction
finding station in North Africa to advise them of their positions when
needed. Problem was, Germans often answered first with wrong location
and direction in impeccable American English so Americans might exhaust
their fuel.

Fair enough. We were borrowing the German Consol navigation signals
over the Bay of Biscane:
http://jproc.ca/hyperbolic/consol.html

Good reading: The Wizard War by R.V. Jones. Covers the battle of the
navigation beams during WWII, V1, V2, and allied scientific
intelligence.

Walter Maxwell worked for the FCC at war`s end in Hawaii and equipped
himself with an Adcock antenna so he could advise lost American aviators
of their positions in the Pacific. I think Walter has published his
story in a radio magazine.

Yep. Walter Maxwell (W2DU) emailed me a copy of his article from the
Jan 2002 issue of QST. Very interesting and well worth reading. I
don't consider it good form to resend what looks like copyrighted
material, so you'll have to either get your copy from the author or
from the ARRL archives:
http://www.w2du.com

Best regards, Richard Harrison, KB5WZI

Marginally related drivel: Most of my experience is with doppler and
rotating antenna type direction finders. Some of my ancient 1994
comments on the technology:
http://www.qsl.net/n9zia/doppler_notes1.txt
http://www.qsl.net/n9zia/doppler_notes2.txt

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

WWII Direction Finder Fix
 

I hate to be a nit-picker, but my article was in the Jan 2007 issue of QST, not
2002. In addition, there were nine Adcocks in Hawaii, and at least 50 on the
Mainland DURING WW2, not just me. The article is not on my web page, as
indicated below, but for those who don't have the above issue of QST, let me
know and I'll send you a copy.

Walt, W2DU


Walter Maxwell worked for the FCC at war`s end in Hawaii and equipped
himself with an Adcock antenna so he could advise lost American aviators
of their positions in the Pacific. I think Walter has published his
story in a radio magazine.

Yep. Walter Maxwell (W2DU) emailed me a copy of his article from the
Jan 2002 issue of QST. Very interesting and well worth reading. I
don't consider it good form to resend what looks like copyrighted
material, so you'll have to either get your copy from the author or
from the ARRL archives:
http://www.w2du.com

Best regards, Richard Harrison, KB5WZI
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

WWII Direction Finder Fix
 

Hello All:

Thank you very kindly for all the great info and e-mails. It is greatly
appreciated.

Jay in the Mojave

WWII Direction Finder Fix
 

Walt,

I had not heard of these Adcock antennas and am interested on the time of
their deployment to Europe. By chance, do you know when that happened?

My uncle was Robert LaMotte, radio operator of the ill-fated B-24 bomber
"Lady Be Good" that was lost in a bombing run over Italy in 1943 and
believed to have ditched in the Med. The ship and crew were found 16 years
later in the Libyan desert, victims of a "read from the back of the loop"
tragedy. They abandoned ship when running out of fuel, believing they were
over water but had overflown their airstrip and in fact were over the
desert. (Google "lady be good" for lots of links)

The family has always followed any news about these types of mishaps, and I
am curious to know how soon after my uncle's loss any technology might have
appeared to prevent the accident.

Thanks in advance for your response,

-larry
K8UT
"Walter Maxwell" wrote in message
...
I hate to be a nit-picker, but my article was in the Jan 2007 issue of QST,
not
2002. In addition, there were nine Adcocks in Hawaii, and at least 50 on
the
Mainland DURING WW2, not just me. The article is not on my web page, as
indicated below, but for those who don't have the above issue of QST, let
me
know and I'll send you a copy.

Walt, W2DU


Walter Maxwell worked for the FCC at war`s end in Hawaii and equipped
himself with an Adcock antenna so he could advise lost American aviators
of their positions in the Pacific. I think Walter has published his
story in a radio magazine.

Yep. Walter Maxwell (W2DU) emailed me a copy of his article from the
Jan 2002 issue of QST. Very interesting and well worth reading. I
don't consider it good form to resend what looks like copyrighted
material, so you'll have to either get your copy from the author or
from the ARRL archives:
http://www.w2du.com

Best regards, Richard Harrison, KB5WZI
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

WWII Direction Finder Fix
 

--
------------------------------------------------------
Antonio Vernucci, I0JX US call: K0JX
Beacons: 50.004 MHz & 70.088 MHz
Home page: http://www.qsl.net/i0jx
e-mail: k0jx {at} amsat {dot} org
------------------------------------------------------
"Jay in the Mojave" ha scritto nel messaggio
umnetworking...
Hello All:

I believe there was a posting here or maybe even in QST that talked about
problems with Radio Direction Finders in aircraft and ships before WWII time
frame. And the fix to repair them so that the Radio Direction Finders (RDF)
did not point 180 degree's the wrong direction.

I am researching information on the WWII Aviation Rescue Boats, (AVR's) 83 and
104 Ft long, Boats used by the US Army during WWII.

I spent 5 years on a 104 AVR Boat, converted into a Commercial Fishing Boat
for Albacore Tuna from 1966 to 1970 as a teen ager.

Any information would be greatly appreciated. Thanks.

Here's a link that shows some of the AVR Boats and spec's.
http://www.warboats.org/crashboat.htm

Jay