# Early radio aerials query



## Shipbuilder (Jun 30, 2005)

Older passenger liners, 1900 to 1930s often had massive aerial arrays consisting of three or four wires rigged on two cross struts between the masts at quite vast distances apart, each with individual downleads to the radio room. What was the idea? Why the multiple wires? Were they for different pieces of equipment? I would have thought they were too close together for some uses!
Bob


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## Mad Landsman (Dec 1, 2005)

Known as a 'T' antennae, the uplink/down feed connects to an appropriate point between the ends - depending on wavelength, which at that time were very long (Low frequency = Long wavelength) 
3 wires was likely the norm because the effect tended not increase much with any more added. 

End connections were usually found in the once common 'random wire' aerials which many will recall being necessary for their crystal sets - Only one wire needed. 

This Wiki article should explain all: 
https://en.wikipedia.org/wiki/T-antenna


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## Shipbuilder (Jun 30, 2005)

Thank you Malcolm,
I understand now. I had searched on Internet, but had not found the Wikipedia answer. 
Many thanks
Bob


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## Mad Landsman (Dec 1, 2005)

Happy to help(Thumb)

It was not only passenger ships. If you look at some of the old warships of the period you will see that some have apparently excessively tall masts rigged especially for the job of carrying two or three wire arrays. Often the stays had insulators as well.


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## BobDixon (Oct 17, 2008)

The vertical part of the aerial was regarded as the most important for radiating the signal, so they looked for as much height as could be obtained. 

However, in order to be able to tune the transmitter into the aerial, the length of the aerial had to reflect the wavelength of the transmission to some extent. So, for the 410kHz to 512kHz frequency range used in more recent years the aerials needed to be as long as could be achieved. The length was even more a factor in the very early years of radio when the frequencies used were much lower and therefore the wavelengths much longer.

The horizontal portion of the aerial was in effect a capacity hat which helped fool the transmitter into thinking it had a longer aerial. Making the horizontal section into two or three parallel spaced wires increased the capacitance and also increased the tunable bandwidth, the latter being important because transmissions were required over a range of frequencies.

The same configuration of aerial could be found on-shore at coast radio stations.


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## Shipbuilder (Jun 30, 2005)

Thanks for further replies.
Bob


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## david.hopcroft (Jun 29, 2005)

As Bob says in #5, spreaders were used at Coast Radio Station.

This thumbnail is of GKZ around the mid to late 50's. The three downleads came together at the telegraph pole to the right of the front door (you will need to + view this to see it). From there to the lead-in insulator in the gable window in the roof. 

David
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The larger building behind GKZ was handily a pub !
The apocryphal story of this is that during the construction of GKZ in 1927, whenever the all powerful Ministry Clerk of Works thought any building materials weren't up to scratch, he would reject them. They promptly went next door to build the pub, or to give it's name - the St Margarets Hotel. 

+


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## Worldspan (Jan 2, 2012)

*Old Aerial Farm (?)*

This is a bit off-topic but hope that it will be permitted, as we do seem to have some experts on old aerials on the forum.

The first attached picture dates from the 1920s or thereabouts and I’m intrigued by what looks like an aerial farm in the background. I do know that the person in the shot was a radio enthusiast although as far as I know he never held a transmitting licence. I have absolutely no idea of the location, unfortunately.

From the same collection is the shot of HMS London (launched 1899, sold for scrap 1920) in which we see cross struts as mentioned by ‘Mad Landsman’.

The thumbnails look very fuzzy ... hope they come out. Sorry but the images are not right. I created small images but they are not thumbnails. Not sure how to proceed.

W


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## Worldspan (Jan 2, 2012)

Hopefully this image of the old aerial will come out.
I'll try to reduced the one of HMS London in the same way.
W


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## Worldspan (Jan 2, 2012)

It's no good ... the thumbnail does not give enough detail to show the old aerial farm in the distant background. Not sure whether it will be possible to improve this image. If anyone can help, pse send me a PM.
W


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## RayL (Apr 16, 2008)

Are there any known instances of lightning strikes down ships' aerials? Could it be said that we R/Os used to lead a life of danger as we sat in front of the equipment?

N.B. I recently became aware that modern houses no longer feature the curly lightning conductor on the corner of the eaves that used to be installed during building as a matter of course. Are we all unprotected nowadays, perhaps?


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## Mad Landsman (Dec 1, 2005)

RayL said:


> Are there any known instances of lightning strikes down ships' aerials? Could it be said that we R/Os used to lead a life of danger as we sat in front of the equipment?
> 
> N.B. I recently became aware that modern houses no longer feature the curly lightning conductor on the corner of the eaves that used to be installed during building as a matter of course. Are we all unprotected nowadays, perhaps?


The 'hip irons' are not lightning conductors. They have no path to earth but are just nailed to the hip timber. You can still buy them, I've got a set of 4 in the shed if you want them. 
Their sole function is to stop the hip tiles sliding off the roof, because the hip tiles have no nibs and are not generally nailed (bonnet tiles being the exception) Modern houses tend to have 'system' tiling where everything interlocks and should not slide off. 

The only 'protection' that many older houses had was the the actual Tv aerial on the chimney - IF the down-lead is properly installed and runs close to ground before rising again to enter the building. It should work in theory but I would not want to test it. 

In the old days there were also lightning 'diverters' available - It consisted of an insulator which you hung on the lowest part of your downlead and then connected a bonding wire to the other end and connected that to an earth rod. I wouldn't want to test that either.


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## trotterdotpom (Apr 29, 2005)

RayL: "Are there any known instances of lightning strikes down ships' aerials? Could it be said that we R/Os used to lead a life of danger as we sat in front of the equipment?"

LOF had a ship where the entire radio station was destroyed by a lightening strike. Can't remember which ship but I heard the RO was on watch when it happened.

John T


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## Worldspan (Jan 2, 2012)

I'm pretty careful when I see/hear a storm coming ... computer off and unplugged, TV disconnected, telephone line unplugged ... and so it was a couple of weeks ago. There'd been a tremendous storm and the following morning when I went into the kitchen to make a cup of tea, the oven fan was going full tilt, the digital display was dead and the oven door wouldn't open. A spike down the mains must have blown the circuit board(s) and spares are no longer available ... so it's been a new oven. 

My grandmother was even more careful: she'd put all the knives away and turn the mirrors round to face the wall!

Aircraft got struck by lightning and this involved resetting all the instruments ... I believe that sailing boats get struck, too. So "Rayl's" comment is interesting ... was anyone aboard a ship whose main aerial got struck?

W


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## sparks69 (Dec 18, 2005)

RayL said:


> Are there any known instances of lightning strikes down ships' aerials? Could it be said that we R/Os used to lead a life of danger as we sat in front of the equipment?
> 
> N.B. I recently became aware that modern houses no longer feature the curly lightning conductor on the corner of the eaves that used to be installed during building as a matter of course. Are we all unprotected nowadays, perhaps?


I'm the living proof of an aerial strike on Boxing Day 1967 in the Med. I thought I was dead and in heaven when I came to and the O/M asked me if I wanted a shot of brandy. Radio Room was a bit fried. The mate shut the door and pulled the mains switch and left it until the morning. Mercury & Elettra were a bit fried, DF OK, Alert fried (not that anyone would notice). Chair broken as it was chained down & I was thrown backwards out into the chart room. I was chatting on the key to a home sick Dutch sparks on a Skywegen ship at the time.


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## Varley (Oct 1, 2006)

One of the best I remember was a telex from Brian French on the Al Farabi:

BY LIGHT OF ALDIS CAN SEE DF LOOPS DANGLING FROM MASTHEAD.

An early GMDSS installation by NERA. All terrestrial and GMDSS LR communications fried. One radar (both downmast) magnetron fried. Other one motor of turning unit fried (I had cunningly used the Thrane and Thrane two aerial version of Sat C so that I could site the two aerials where they would not be susceptible. DNV surveyor at installation wouldn't have it). Luckily the good old JUE 35 A simply blew a fuse and restarted without a fuss.

What was impressive was that she left the first port of Japan fit for A2 and back to full capability by before leaving the last.

Had a few others but none with DF loops removed. Although most on pre GMDSS vessels I am convinced that the level of integration WITH COPPER heralds a disaster in the making. We did have a strike near or on the foremast of an Ethylene carrier which hung up both the redundant communications link between compressor room and TGE control system. One came back up the other didn't.

Lost both radars of a Transpetrol vessel in Mexico (as well as some brown trouser causing copper tubing projectiles from the radio room). Upmast - inevitable.

I recommend towing a skyscraper behind or my HFCTALD (helium filled conductively tethered anti-lightning dirigible).


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## david.hopcroft (Jun 29, 2005)

On my first ship, a tanker on the PG to Philippines run (Back to Bataan !!) traversing the Malacca Straits in ballast, an early morning storm was a rude awakening to all. It seemed to have hit somewhere forward and reverberated through the empty tanks. More frightening was that it flashed over the gases at the top ventilators on the goalpost mast forward. The OM turned everyone out just in case. 

Another weird experience was also in the Malacca straits. The aerial distribution box was on the bulkhead. As I passed under it, I had the distinct impression that I heard a 'splat' sort of noise behind me. I concluded it was a static charge that 'dripped off' and landed with a splash. It certainly made my hair stand on end !!

David

RayL - think you might remember GHFJ ?

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## RayL (Apr 16, 2008)

Thanks David! I certainly do remember GHFJ (Naess Sovereign) and it entered my mind at once as you started your description. I never did the Bataan run so I can't emulate McArthur like you can. I do remember a number of occasions in the Med when a wave hit the bow and had us all bouncing up and down as the 'bubble' travelled the length of the ship. Sometimes it alarmed me sufficiently to power up the transmitter in case sudden disaster struck (as Torrey Canyon proved could happen shortly after that voyage).

Regards as ever.


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## Varley (Oct 1, 2006)

"fizzing" in the MIMCO aerial switch box if unwise enough to be isolated in the tropics I would have thought quite common. Certainly was on Stonehaven on the Eilat/Persia run.


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## Naytikos (Oct 20, 2008)

IMR used to fit a control panel which amongst all the switches for audio routeing and other extraneous functions had a group of open sockets into which one plugged copper loops to select receiving aerials. Loud clicks accompanied by arcing exuded from these whenever the outside humidity was high, even if there was no lightning around. 
It was interesting that so much static could build up presumably just from the movement of the aerials through the air.
After experiencing this the first time, I always installed a couple of 1N4004 or similar diodes, back to back, from each receiving aerial feeder to ground. Sometimes they got blown to bits and had to be replaced, but it saved the receiver front ends.


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## david.hopcroft (Jun 29, 2005)

Ref my #18, I found this in my collection. It was of the Naess Sovereign/GHFJ at anchor at Ras Tanura sometime during 1963. It shows the vents quite clearly. 

There was a new AEI T50MH main Tx fitted when I joined, but the G12 remained as main Rx with the usual AEI Emergency rack.

David
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## sherman (Sep 22, 2009)

Did any one have this experience. I used to stay in a hotel that had a plastic hand rail on the stairs and when my hand left the rail at the bottom I would hear a CLICK and get a shock in my arm


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## Mad Landsman (Dec 1, 2005)

sherman said:


> Did any one have this experience. I used to stay in a hotel that had a plastic hand rail on the stairs and when my hand left the rail at the bottom I would hear a CLICK and get a shock in my arm


One Office that I worked in had carpet tiles throughout which we discovered caused significant static charge in anyone walking about. 
It became standard practice to slap anything metal with an open hand before doing attempting to use a handle etc. That way one discharged over a large area rather than just the fingertips and it did not hurt as much. (Ouch)


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## Ron Stringer (Mar 15, 2005)

sherman said:


> Did any one have this experience. I used to stay in a hotel that had a plastic hand rail on the stairs and when my hand left the rail at the bottom I would hear a CLICK and get a shock in my arm


Static build-up is still a common phenomenon in many modern buildings. Most frequent occurrence is when reaching for metal handles on doors or drawers or (from the metal fascia plates) when pressing the buttons that summon lifts/elevators. For the latter I prefer to hold a metal door (or car) key and press the button with that. 

I learned that trick about 40 years ago, whilst staying at the then newly-built _Amaranten_ hotel in Stockholm which had the most vicious static I ever encountered. The sound of the 'click' was like a stick being broken and the arc took place about 1 cm before your finger reached the button. At first I used to use the stairs to the 5th floor rather than use the elevator because the discharge was so painful. Then I had the idea of using the room key (before the days of modern entry systems) and found that there was no longer any pain involved. 

I always wore leather-soled shoes, which I held partially responsible for the size of the jolt from the static; a colleague who preferred rubber soled shoes hardly felt a thing, just a mild tingle.


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## djmorton (Apr 10, 2006)

Ron,
Remember the carpet tiles in the 'Dem Room' in Westway. Stroll across 'em and put your hand on metal area (e.g. chrome handles) of equipment and 'zap'............

I suspect many a visitor or prospective customer was not impressed.

Rgds,
Denis


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## Cisco (Jan 29, 2007)

david.hopcroft said:


> Ref my #18, I found this in my collection. It was of the Naess Sovereign/GHFJ at anchor at Ras Tanura sometime during 1963. It shows the vents quite clearly.
> 
> There was a new AEI T50MH main Tx fitted when I joined, but the G12 remained as main Rx with the usual AEI Emergency rack.
> 
> ...


Totally 110% off topic.... 

Interesting photo.... note the 4 tripods for rigging jackstays(?) to hang the windsock thingos off when gas freeing. 

And the dry cargo hatch complete with 2 derricks... can anyone recall ever loading anything in there?


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## sherman (Sep 22, 2009)

I had another problem with static when I was working. I worked for a forklift company, service and mataintance. A factory I used to go to had electric forklifts and a floor covered with rubber like tiles. The problem was that when the drivers were getting off the truck they were getting electric shocks. The factory came to a stand still as the drivers would not drive the trucks. I was sent in to them and I fixed the problem by bolting a battery earth strap to the back axel so that the strap tutched the floor


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## david.hopcroft (Jun 29, 2005)

Cisco - Think the Mate might have 'hidden' his butterworth machines in there when at Bataan. Anything not bolted down was liable to 'walk' there.

Found this too. Must have taken it at the same time as the other.

David
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## Bill.B (Oct 19, 2013)

On Swiftnes, Jebsens, we took on Chinese bunkers in Shanghai in 75. The engineers had been communicating with the company that the stuff was very bad and an alternative sourced. However we ended up loading it. Sailed from Shanghai to Nauru for phosphate load. Once we switched to heavy oil the smoke that came out of the funnel would have put a coal burner to shame. Unfortunately both main and emergency aerials were supported by masts either side and aft of the funnel. Once the exhaust crossed the wires the radio room became a snapping flashing place of wonder. The aerials constantly arced over in the Redifon switch box and between the feeders. Grounding them made not a lot of difference. As can be imagined the static on the receivers was overwhelming. Only solution was to lower the aft ends of both to below stack gas level, about 10ft of the deck, and sail like that. My problems were easily solved but the engineers went through hell changing out exhaust valves and units for months after. Eventual we heard not to bunker in China if possible.


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