What are these cables for ?

[Kobal2]

Probably a basic question, but this has been bugging me for a while : on type VIIs, there are two cables that run from the conning tower to the stern, and one that runs to the prow. I have also noticed that most small ships and destroyers also bear cables running from prow to stern and passing by their mast tops. What are those cables, and what are they used for ?

[gordonmull]

As far as I can tell these are actually radio antennae, with the fore cables for transmission and the aft for reception.

Please correct me if I'm wrong, someone.

Well if it is anything like the aviation antenna. I t works like this.

Improved radio reception can sometimes be attained by rotating the antenna to a particulare positon. Two antenna exist, the sense antenna, which extend fore and aft from the conning tower and the directional loop which is the round antenna on the starboard side of the conning tower.

Together the antenna can give the operator the direction of the transmitter.

Remember the time B4 VOR/DME and GPS, this was state of the art navigation and position reference.

[gordonmull]

So theoretically a u-boat could intercept an enemy transmission and glean its bearing from the antennae? Don't quite get how this works and the "must suss out how everything works" part of me is now in overdrive......

[don1reed]

If configured as a dipole antenna, the maximum radiation is 90° (off the beams of the boat) from it's axis.

If configured as an end-fed (from the turm to the bow) long-wire (depending on the frequency), the maximum radiation is approx 20° off each bow.

Like their early version of radar, the boat had to be rotated for best transmission/reception.

Something I might add, that back during those war years the airways (broadcast spectrum) were not as corrupted as they are today, where bandwidth is sorely coveted and competed for.

[Kobal2]

Haaa, I see, I thought they were some kind of navigation aid, or maybe something to hoist strings of message flags.

Thanks, guys !

[gdogghenrikson]

I thought they were something to hold on to, like a raileng

[slow_n_ez]

Hummmm I thought they were used to transfer external torpedos to help get them inside .. I think torpedos weight like 3000 pounds or something like that ..............

[don1reed]

...you might say they were multifunctional cables...

--they aided in avoiding entanglements, ala net-cutter.
--they were a part of the antenna system, notice the large strain-relief insulators (egg shaped) near the turm and bow. The transmission line comes out of the turm via a feed-thru insulator on the forward side of the turm.
--they were strong enough to support the weight of transferring torpedoes around.
--laundry line.
--safety cable for the deck crew to go forward or aft during a blow, etc.
--I've seen pictures of them using it as support for a canvass awning during the heat of the summer in port.

The funkmaat would no doubt inform the crew what the transmission schedule was. No one likes to get RF burns, especially from the the 200 watt transmitter aboard. Like in todays world, all the RF radiators get turned off whenever men go aloft for repair work. It was no different then.
The list could go on, it's up to your imagination...

[Floater]

Torpedoes were transferred using an entirely different system: a winch mounted on the tower with a cable going directly to the torpedo. Nothing to do with the radio cables.

[kiwi_2005]

Your all wrong they're for to hang the undies on when its a sunny day

[Mowgli]

From my days in the RN as a Radio Operator, I seem to remember that the long wire strung aerials were for low frequency reception. Usually it was the higher the frequency the smaller the aerial.

With a low frequency and a stong enough transmitter there would be good ground/sea coverage, with higher frequencies you could have skip problems, be almost on top of the transmitter and recieve zip.

[don1reed]

Roger that, Mowgli--in the vicinity of 160m and lower, i.e., VLF.; however, antenna length is inversely proportion to frequency, so it is possible to have a longwire ant. for the higher freqs. The forward lobes of the rf pattern still have the benefit of dB gain and directivity similar to a rotatable beam ant. I guess it all depended on what type of impedence matching system was down in the radio-shack.

@Floater: Agreed. I believe "Teddy" Suhren's crew when transferring aals from aft external to forward, just used the antennae cables for teather rather than actual lifting support aboard the U564 when they floated the torpedoes forward...or not.

[benetofski]

...to lsten to (and talk) to "Goliath".....

[Jan7]

I am Juan, spaniard, y very new in this Forum.

Friends: I'm a Diexist and SWLer: all your comments are very valid. You are invited to a tour in the web that I colaborated:

http://www.u-historia.com --> Técnica --> Artículos Técnicos --> Equipos de Rádio en los U-boots

or http://www.u-historia.com --> Técnica --> Visita Guiada --> Comunicaciones --> Sala de radio