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Author Topic: WWII listening post in U.S. heard radio signals from thousands of miles away  (Read 6561 times)

Brian Tannahill

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According to an article in the Providence (Rhode Island) Journal, during World War II the U.S. Federal Communications Commission operated a radio listening station from a site called Chopmist Hill, in Scituate, Rhode Island, close to Providence.

From this location, "because of some geographic and atmospheric anomalies" the U.S. government was able to listen to German and Japanese military radio transmissions over distances of thousands of miles.

Radio receivers and direction finders at the site were connected to 85,000 feet of antenna wire strung below the tree line to keep them out of view.

The site was able to obtain radio signals originating in Germany, central Europe, north Africa, and the Pacific.  They picked up weather forecasts from central Europe, which were useful for planning bombing runs.  They listened in on tank-to-tank communications among Rommel's Afrika Corps.  I was a radio technician in the Air Force quite a few years ago, and while I know nothing about the radios used in tanks I would guess that they are fairly low-powered.  I am curious how they compare to the radio in Earhart's Electra.

The Chopmist Hill station picked up signals from distances that are roughly the same as the distances from Gardner island to some points in the United States.

Providence to Cairo: 8,767 km (according to Google)
Providence to Berlin: 6,139 km

Chopmist Hill was listening to Japanese messages in the Pacific before Pearl Harbor.  The article doesn't say where in the Pacific these messages originated.  The Pacific is a big place but to pick a couple of locations:
Providence to Honolulu: 8,159 km
Providence to Midway: 9,142 km

Nikumaroru to St. Petersburg, Florida where Betty Klenck may have heard Amelia: 10,429 km
Nikumaroru to Rock Springs, Wyoming where Dana Andrews may have heard Amelia: 8,345 km

While TIGHAR  has worked hard to establish whether it's plausible, or even possible, for radio signals from Niku to have traveled this far, it appears that a few years later the station at Chopmist Hill was consistently and reliably receiving signals over the same distances.
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Martin X. Moleski, SJ

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While TIGHAR  has worked hard to establish whether it's plausible, or even possible, for radio signals from Niku to have traveled this far, it appears that a few years later the station at Chopmist Hill was consistently and reliably receiving signals over the same distances.

That is an awesome first post, Brian.

Detailed.

New information.

With links!

Welcome!   :)

LTM,

           Marty
           TIGHAR #2359A
 
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Steve Treadwell

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They listened in on tank-to-tank communications among Rommel's Afrika Corps.

Here's some info on German tank radios - not a lot of power.

http://www.armyradio.com/publish/Articles/William_Howard_German/German_Tank_Radios.htm
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Brian Tannahill

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The link Steve posted had exactly what I was looking for.  German tank radios, as described here, were AM units of 10, 20, and 30 watts.  The 30 watt unit operated on frequencies of 1110 to 3010 kcs.  There's no information on frequencies for the 10 or 20 watt radios.

The Electra had a 50 watt AM radio transmitting on 3105, 6210, and 500 kcs.  So Earhart was broadcasting with significantly more power than the tanks in north Africa that were heard in Rhode Island.
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Steve Treadwell

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The link Steve posted had exactly what I was looking for.  German tank radios, as described here, were AM units of 10, 20, and 30 watts.  The 30 watt unit operated on frequencies of 1110 to 3010 kcs.  There's no information on frequencies for the 10 or 20 watt radios.

The Electra had a 50 watt AM radio transmitting on 3105, 6210, and 500 kcs.  So Earhart was broadcasting with significantly more power than the tanks in north Africa that were heard in Rhode Island.


Brian, the link I posted did have info about the 10 and 20 watt radio frequencies - it was in the photo captions, but not further down in the main body of the article where the 30 W.S. is discussed.  The 10 W.S. c freq. and the 20 W.S. freq. was 27.2-33.3 KC and the 10 W.S. h freq. was 23-24.95 KC.

EDIT: The caption on the 10 W.S. c transmitter lists the frequency range as 27.2-33.300 KC and the 20 W.S. transmitter frequency is listed as 27.2-33,300 KC (I assume the comma in this last figure should be a decimal point).  But that seems like too low frequency - wouldn't you need a really long antenna for those frequencies?  Could it be 27.3-33.3 MC (MHz)?   /EDIT

So given the proper location and what must have been one heck of an antenna, and maybe also the right conditions (not sure how the sunspot cycle would have affected this during the early 40's), it is possible to pick up really low powered transmissions from a really long distance.  Maybe adds some credibility to the Earhart transmissions received in the U.S., though I'd bet none of those people had anywhere near the antenna that they had at Chopmist Hill.  Still, weird stuff happens if conditions are just right - I live in the Dallas, TX area and about 25 or 30 years ago I picked up a TV station in Buffalo, NY - way too snowy to be watchable, but I did see that it was in Buffalo (don't remember the call letters of the station) and my antenna was a simple pair of "rabbit ears" on the set top.

« Last Edit: September 23, 2015, 02:24:54 PM by Steve Treadwell »
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Craig Romig

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Steve I have also picked up am radio from Chicago about 60-90 miles south of Kansas city. At night in my truck. Sitting in my driveway.
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