Technology and Operations
This forum is for discussing technological & operational matters pertaining to U-boats.
German U-boats direction finding
Posted by:
Funkmeister
()
Date: July 26, 2009 09:35AM
Hello all!
On 22 January 1944 the B.d.U. ordered to U-boats to make experiments, testing of possibilities of direction finding in the Atlantic. The U-boats had to take bearings of Very Low Frequency (VLF) coastal transmitters located on the both sides of the Atlantic and to fix the U-boats positions, and to check the accuracy of such obtained positions by means of dead reckoning and astronomical navigation. The transmitters worked on the frequencies around 20 kHz.
The transmitters were German but also British, American and Spanish. It was good idea, actually. The transmitters' positions were known, they worked on VLF and the frequencies are the best for direction finding.
But, I am not sure if the U-boats could to take bearings when they were submerged.
Of course, the Germans received VLF messages from their transmitters Nauen and Goliath when the U-boats were submerged, by means of DF receivers and their loop antennas.
But, it is different when you just receive message or when you have to take bearing.
There is not perfect accurate bearing because radio waves pass through different media, line between land and sea etc etc. Yes, VLF radio waves are the best for bearing, but still, there is always some kind of inaccuracy.
I am sure that even when a U-boat was submerged that radio operators were able to take some kind of bearing by rotating the loop antenna around its axle, but how bearing obtained on such way was? After all, the radio signal passed through different mediums, air and water, in its way from the transmitter to the loop antenna (of submerged U-boats).
There must be some kind of refraction, but how big the reflection was?
After WW2 the Omega navigational system has been introduced. Omega work on VLF, between 10 and 14 kHz. Submerged submarines used the system because VLF could be received under the surface. A submarine Omega receiver measures phase difference of signals and by means of special Omega charts and those days by Omega receiver which display directly the submarine position they could fix the position.
I mean, if submerged submarines could to use Omega system, which worked on VLF (10-14 kHz), was it possible for WW2 (submerged) U-boats to take bearings on land VLF transmitters which worked on similar frequencies, around 20 kHz.
It is pure technical question, and on my shame I don't know the answer
Best regards!
Funkmeister
On 22 January 1944 the B.d.U. ordered to U-boats to make experiments, testing of possibilities of direction finding in the Atlantic. The U-boats had to take bearings of Very Low Frequency (VLF) coastal transmitters located on the both sides of the Atlantic and to fix the U-boats positions, and to check the accuracy of such obtained positions by means of dead reckoning and astronomical navigation. The transmitters worked on the frequencies around 20 kHz.
The transmitters were German but also British, American and Spanish. It was good idea, actually. The transmitters' positions were known, they worked on VLF and the frequencies are the best for direction finding.
But, I am not sure if the U-boats could to take bearings when they were submerged.
Of course, the Germans received VLF messages from their transmitters Nauen and Goliath when the U-boats were submerged, by means of DF receivers and their loop antennas.
But, it is different when you just receive message or when you have to take bearing.
There is not perfect accurate bearing because radio waves pass through different media, line between land and sea etc etc. Yes, VLF radio waves are the best for bearing, but still, there is always some kind of inaccuracy.
I am sure that even when a U-boat was submerged that radio operators were able to take some kind of bearing by rotating the loop antenna around its axle, but how bearing obtained on such way was? After all, the radio signal passed through different mediums, air and water, in its way from the transmitter to the loop antenna (of submerged U-boats).
There must be some kind of refraction, but how big the reflection was?
After WW2 the Omega navigational system has been introduced. Omega work on VLF, between 10 and 14 kHz. Submerged submarines used the system because VLF could be received under the surface. A submarine Omega receiver measures phase difference of signals and by means of special Omega charts and those days by Omega receiver which display directly the submarine position they could fix the position.
I mean, if submerged submarines could to use Omega system, which worked on VLF (10-14 kHz), was it possible for WW2 (submerged) U-boats to take bearings on land VLF transmitters which worked on similar frequencies, around 20 kHz.
It is pure technical question, and on my shame I don't know the answer
Best regards!
Funkmeister
| Subject | Written By | Posted |
|---|---|---|
German U-boats direction finding
|
Funkmeister | 07/26/2009 09:35AM |