# MF+HF Antenna cable ~ deep sea:



## les.edgecumbe (Dec 24, 2007)

Can anyone give me the spec for the cable used as mf/hf radio antenna on deep sea ships. 

Need to know :

Material

No. of strands, and gauge of strands

overall diameter of the cable.

Source


TIA

Les.


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## Coastie (Aug 24, 2005)

I'm no expert but I would have thought that if it wasnt balanced feeder then it would probably be half inch low loss 50 ohm coaxial cable connected to a "N" type plug.


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## Ron Stringer (Mar 15, 2005)

les.edge***be said:


> Can anyone give me the spec for the cable used as mf/hf radio antenna on deep sea ships.
> 
> Need to know :
> 
> ...


Les,

The material was phosphor-bronze wire.

There were 7 strands.

And as something that was as basic to me as breathing, it amazes me that I cannot remember the gauge of the individual strands. I'll ask some of my former colleagues and let you know what they remember.

The earthing wire was definitely 7/.029" tinned copper wire but the antenna wire used for transmitting was heavier. There were two types of suspended antenna wire - both phosphor bronze - a lighter one used for receiving antennas (may also have been 7/.029") and a heavier one for transmitting antennas, which I think was 7/.040" but that is where my doubts come in. I'll check and get back.


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## les.edgecumbe (Dec 24, 2007)

Thanks Ron ~ should havethought of you in the first place! I did also get a reply from an ex MIMCo E Ham man who you may have met....Geoff Stocks?

Les.


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## gwzm (Nov 7, 2005)

Hi,

Usually used 7 strand 0.064" inch phosphor bronze for receiving aerials and 13 strand 0.064" phosphor bronze for transmitting aerials. The short links in the safety loops were usually 5 strands for the transmitting aerials. I don't recall ever having safety loops on a receiving aerial.

gwzm


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## Troppo (Feb 18, 2010)

A properly spliced and rigged main antenna is a thing of beauty!

My Dad was an ex-MN Deck Officer - he taught me to splice rope and wire. A very useful skill.

I remember replacing the main ant on one ship - the difference in antenna current was amazing (as it should be).


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## Tony Selman (Mar 8, 2006)

There are some people on here with good memories. However much I worked on aerials I would never have known the gauge of transmitting or receiving aerials. I agree with GWZM I cannot ever remember a safety loop on a receiving aerial. Off the top of my head I wouldn't have thought the transmitting aerials were 13 strand but as both GWZM and I worked for the same company and his memory is clearly better than mine I will go with his figure!
I used to enjoy splicing aerials and often used to think that the job done properly made the aerial stronger than it was in the first place. Only time I did not enjoy doing it was on Cunard cargo ship 'Samaria' after a mighty blow off the South Coast of Ireland and every wire aerial on the ship broke overnight. I fixed the main aerial on the foredeck in a force 9 with the bosun keeping a weather eye on me and it is fair to say I was not overly happy with copious amounts of the North Atlantic sloshing around. Fastest splicing job I ever did that's for sure.


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## Ron Stringer (Mar 15, 2005)

Safety loops were only required by UK Radio Rules for transmitting antennas. The idea was that, should the masts from which the antenna was suspended be caused to move apart, stretching the antenna beyond breaking point, only the weak link in the safety loop would snap. That would allow the antenna to lengthen by the extent of the safety loop and prevent it from snapping and being brought down. Although the antenna overall length was increased, it would still be possible to tune the transmitter to accommodate the change and permit the transmission of urgent messages without first having to re-rig a snapped antenna.

Definitely the MIMCo-supplied antenna wire was only 7-stranded, I repaired a lot of them in my time. The safety loop was made by removing some of those strands. I recall 7/.064" (or 7/1.7mm when we went metric) as being the battery cable (i.e. very thick) which points me to 7/.040" for the transmitting antenna wire. But I'll check and get back to you.

PS Anyone with an old Marconi transmitter handbook will have an installation drawing in it. Some of them will specify the type of wire and its make-up as used for the antenna.


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## Troppo (Feb 18, 2010)

Safety loop/weak links were introduced in WW2, from memory.


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## andysk (Jun 16, 2005)

I was part of the group that specified and supplied shipyards with the drawings etc for new builds and refits at IMRC for about 6 years, but I am blowed if I can remember the aerial wire specs, beyond being 7 strand phosphor-bronze, with two strands removed for the safety link.

Like Tony, I too used to enjoy splicing, one of the better maintenance jobs was when at anchor for a couple of weeks off Dar es Salaam was to refurbish the wire aerials. That took some doing, as the guy I relieved on that ship used to inspect the aerials etc by using a pair of binoculars from the main deck, so nothing had been freed and greased for some considerable time.


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## Naytikos (Oct 20, 2008)

I have to hand a 24M coil of virgin transmitting antenna wire issued by SAIT in 1980 or thereabouts. It is 7/.044 phosphor-copper.

I rather doubt anyone would use phosphor-bronze for wire as it is quite a hard alloy and often used for ship's propellors; the conductivity is also substantially lower than plain copper. It was (is?) common to add a small percentage of phosphor to soft-drawn copper to give it more corrosion-resistance.


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## Ron Stringer (Mar 15, 2005)

Naytikos said:


> I have to hand a 24M coil of virgin transmitting antenna wire issued by SAIT in 1980 or thereabouts. It is 7/.044 phosphor-copper.
> 
> I rather doubt anyone would use phosphor-bronze for wire as it is quite a hard alloy and often used for ship's propellors; the conductivity is also substantially lower than plain copper. It was (is?) common to add a small percentage of phosphor to soft-drawn copper to give it more corrosion-resistance.


I am ready to believe you, since I too always had doubts about the use of such a hard material as phosphor-bronze. Mind you, when struggling to make up wire antennas on deck on a South Shields winter's day with bare hands and pliers, I could have sworn that they had supplied spring steel or titanium. Soft and pliable did not come into it. 

However that is what it said on the installation schedules listing what was to be supplied to a ship. However I know that, in my time, the nomenclature containing the parts/materials descriptions was kept in a big, loose-leaf book and maintained by a clerk who would not have known the difference between phosphor-bronze and phosphorescence. So the description might not have been too accurate.

As for the actual material in stock - we got whatever the approved supplier had been delivering since the company first started buying antenna wire, when Marconi was still alive! By the time that "approved suppliers" were done away with (and every new purchase involved obtaining quotations from at least 3 suppliers), wire antennas were a thing of the past and the mast antenna was king.


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## PeterY (Jun 24, 2008)

Speaking as a former radio surveyor, the specification for a weak link was one third of the number of strands of antenna wire. The complication was always the number of suppliers of weak links - radio companies. This was always the weakest link.


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## Troppo (Feb 18, 2010)

Ha ha ha!

Yep.....


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