How does the Marconi Wireless equipment work?!

[Cam Houseman]

Hi!
A question I have is, how does everything in the Marconi Room, work? The purpose of each equipment? What is the purpose of the Silent Room?

I know some stuff, like the Panel with the handles, they cranked the power up when Titanic was losing power. But how does it work? Jack Phillips and Harold Bride, did they have shifts? Did Bride ever get to use it?

What's the name of the "Tappy thing" that they send out the signals with? How does that work?

What is the AC/DC (not the band ) panel?

Wish Parks was here. I bet he'd engage this question with enthusiasm and blow my mind lol

thank you!

 

[ihavecoins]

Wireless telegraphy - Wikipedia

 

[Steven Christian]

Hi!
A question I have is, how does everything in the Marconi Room, work? The purpose of each equipment? What is the purpose of the Silent Room?

I know some stuff, like the Panel with the handles, they cranked the power up when Titanic was losing power. But how does it work? Jack Phillips and Harold Bride, did they have shifts? Did Bride ever get to use it?

What's the name of the "Tappy thing" that they send out the signals with? How does that work?

What is the AC/DC (not the band ) panel?

Wish Parks was here. I bet he'd engage this question with enthusiasm and blow my mind lol

thank you!

It works pretty good.

 

[M.A.S.]

I just read here in this science museum article that those Marconi wireless operators heard all the messages in the same frequency, which is why they were annoyed when ice warnings interrupted their seemingly important work of relaying the passengers' messages. I knew that the messages were written down by them, but I didn't have a clear picture in my mind of how they received them. For example,

"Since Titanic's wireless operators were transmitting over the same frequency as other ships, and the channels were jammed with passenger communications, several ice warnings from other vessels were either missed or ignored."

As sad as it is that this set-up didn't prevent the shipwreck, at least it was thanks to the Marconi device that they got a hold of the Carpathia. Otherwise, even the survivors on the lifeboats wouldn't have made it. And good thing they improved the system after that, so it worked better and they got their priorities straight.

"WHAT WAS THE IMPACT FOR RADIO COMMUNICATION?​

Hard lessons were learned from the disaster.

Soon afterwards, the International Radiographic Conference in London passed new regulations for wireless communication on board ship.

Perhaps the most important of these were that first-class passenger ships had to set a permanent 24-hour radio watch, use the same wavelength to transmit signals and maintain radio silence at regular intervals to listen for distress calls."

This explains a lot more:

Titanic, Marconi and the wireless telegraph | Science Museum

The dramatic rescue of over 700 survivors from the Titanic disaster was made possible by wireless telegraphy.

www.sciencemuseum.org.uk

 

[Steven Christian]

I just read here in this science museum article that those Marconi wireless operators heard all the messages in the same frequency, which is why they were annoyed when ice warnings interrupted their seemingly important work of relaying the passengers' messages. I knew that the messages were written down by them, but I didn't have a clear picture in my mind of how they received them. For example,



As sad as it is that this set-up didn't prevent the shipwreck, at least it was thanks to the Marconi device that they got a hold of the Carpathia. Otherwise, even the survivors on the lifeboats wouldn't have made it. And good thing they improved the system after that, so it worked better and they got their priorities straight.





This explains a lot more:

Titanic, Marconi and the wireless telegraph | Science Museum

The dramatic rescue of over 700 survivors from the Titanic disaster was made possible by wireless telegraphy.

www.sciencemuseum.org.uk

Marconi Installation in Titanic

 

[M.A.S.]

Wow! :O All that mechanical engineering stuff went over my head (but I did read every sentence). Very fascinating. Wish there were more illustrations... I was struggling to visualize everything. And wow, too, about the "way back" references -- all from around that time.

 

[Gordon Mooneyhan]

A spark gap transmitter is analogous to using lightning to send a message. Next time you're near a thunderstorm, turn on the A.M. radio in your car and you'll hear "bursts" of static corresponding to lightning strikes. And they won't be at just one frequency but will be spread across the band. Every time the key would be pressed, a spark would arc across the gap creating the "static" that would either be a dot or a dash. That is similar to how a spark gap would sound.

I have a friend who is an Amateur Radio operator. He has a key that is a replica of the key used on the Titanic. He finds it tiring to try and send 12-15 words per minute using the key. He was shocked when I told him that the Marconi Wireless operators had to be able to send at 25 words per minute.

 

[Clifford Wright]

A spark gap transmitter is analogous to using lightning to send a message. Next time you're near a thunderstorm, turn on the A.M. radio in your car and you'll hear "bursts" of static corresponding to lightning strikes. And they won't be at just one frequency but will be spread across the band. Every time the key would be pressed, a spark would arc across the gap creating the "static" that would either be a dot or a dash. That is similar to how a spark gap would sound.

I have a friend who is an Amateur Radio operator. He has a key that is a replica of the key used on the Titanic. He finds it tiring to try and send 12-15 words per minute using the key. He was shocked when I told him that the Marconi Wireless operators had to be able to send at 25 words per minute.

I have made quite a study of early wireless and in my library have all the operator manuals for the various Marconi and other wireless systems.
Firstly the Morse key. As a radio Ham since 1958 I still use Morse quite often and use a 1919 RAF straight key. Even I, at 82 can easily send at 18/20 words per minute and the Titanics main transmitter used an ingenious resonant relay that made the key much lighter (and safer) to use. It was arranged so it only keyed the transmitter when the AC power was passing through zero and greatly reduced the surge problems you would otherwise have had. As to spark frequency. The 5 kW transmitter used on the Titanic was fitted with a rotary spark gap mounted on the shaft of the motor generator that converted 110 volt DC ship power to 80 volt 400 Hz. This went through a transformer and could be as high as 10,000 volts at the spark gap. Because the spark gap was mechanically locked to the alternator the position of the spark gap relative to the AC could be easily set up.
The result was an 800Hz spark frequency as both negative and positive half cycles created a spark, not 400Hz. The rapid rotation meant that the spark was quickly broken, allowing the primary tuned circuit to "ring" freely with less damping and therefore gave a relatively cleaner signal.
The usual receiver was a magnetic detector which worked on the same principle as an old tape recorder erase. The wirelesss signal partly demagnetised a moving iron wire and the change was picked up in a coil designed to match the 120 Ohm Headphones used. This was not the most sensitive detector, but it was very rugged and as long as the clockwork drive motor was wound up it would keep on receiving. The Titanic also had crystal detectors and a Fleming diode receiver. This was mainly used for long wave ~45 kHz reception of news broadcasts from Clifden in Ireland or Cape Race and suppied copy to the on board newspaper. BTW I have built working models of most of these devices the transmitter was a mere 25 Watts but gave a good loud 400 Hz signal when fed with 200 Hz ac power. Getting fine enough iron wire was the biggest problem for the "maggie", I used an old 78 rpm clockwork record player motor to drive the band and the position of the permanent magnets relative to the band was quite critical for best results. The headphones used were exactly the same S.G Brown type that Marconi's usually supplied. If anyone needs any detailed information on this subject I am most happy to help.
FYI there were only 2 transmitting frequencies 1 Mhz, 500 kHz and a bit later 666kHz and transmitters were usually set up just for these. Don't forget it was much more complex that just turning a dial. Apart from tuning and adjusting large high voltage coils and capacitors the spark gap voltage also needed to be reset.

 

[Steven Christian]

Interesting and informative post William. I understood most of what you were explaining. One question though. What did you use to get the 200 hz power feed? An electronic frequency generator or a variable speed alternator? Just curious. Have worked on many 60 hz and 400 hz generators both single and 3 phase but never recall seeing a 200 hz gen. Cheers.

 

[Clifford Wright]

Well Steven after several years of looking for a 28 volt DC to 80 volt 400 Hz aircraft motor/alternator
I gave up and did a little cheating. The 200 Hz came from a computer UPS with the clock crystal raised from
4 MHz to 16 MHz (as far as I could push it). That way at least I got a reasonable 400 Hz spark frequency.
It was a modified sine wave so the spark gap had to adjusted to spark on the top of the waveform.
I would really have loved to get hold of one of those nice little 400 Hz units. Mainly used to drive servos and
some of the cockpit instrument I think. The whole thing could have been very authentic then. BTW the Jigger
coil was actually from a Marconi 1/4 kW spark set and was actually what gave me the idea for the design.
If you look up "Wireless World" sometime in the 90's you will see a photo of my station in the letters columns.
Cliff ZL1BDA

 

[Steven Christian]

Well Steven after several years of looking for a 28 volt DC to 80 volt 400 Hz aircraft motor/alternator
I gave up and did a little cheating. The 200 Hz came from a computer UPS with the clock crystal raised from
4 MHz to 16 MHz (as far as I could push it). That way at least I got a reasonable 400 Hz spark frequency.
It was a modified sine wave so the spark gap had to adjusted to spark on the top of the waveform.
I would really have loved to get hold of one of those nice little 400 Hz units. Mainly used to drive servos and
some of the cockpit instrument I think. The whole thing could have been very authentic then. BTW the Jigger
coil was actually from a Marconi 1/4 kW spark set and was actually what gave me the idea for the design.
If you look up "Wireless World" sometime in the 90's you will see a photo of my station in the letters columns.
Cliff ZL1BDA

Very creative and innovating solution you came up with. I'm impressed. Over clocking the UPS. I wouldn't have thought of that. I probably would have tried something more primitive like cutting out half the poles on a 400 hz generator and adjust the rpm's manually to get a stable 200 hz. Don't know if that would work but if it did you'd get a pure sign wave instead of a modified one. But maybe the modified sign was better for your application as I've noticed on some the peak voltage at the top of the waveform seems to last a little longer than a pure sign wave. At least that's the way it looks to me on the scope. I worked on jets that had RATS on them. Ram Air Turbines that popped out to generate emergency power. Maybe there's some surplus ones floating around out there somewhere. If I remember right they were regulated to run at 400 hz but I could be wrong about that. They were fairly small units. I understand how the individual components works in radio and other devices. But I wouldn't know how to put them together to get a transmitter/receiver to work. That's out of my league. My buisiness was working on control systems that ran power generators and peripheral systems. Not exactly rocket science. By the way....I have read that Marconi claimed he invented the jigger coil. But the truth seems to be that he um "borrowed" the idea from somebody else. Maybe from Tesla. Well this has been interesting but were straying too far from Titanic. The mods would probably appreciate if we didn't get too far off track. I will go look and see if I can find your system you built. Cheers.

 

[Steven Christian]

Clifford. I couldn't find that system you mentioned. But I did find many of your posts on a radio site. You and your fellow posters there really know your stuff about radio. Magnitudes of order above my limited knowledge on the subject. Cheers.

 

[Clifford Wright]

Well Steven I've had my Ham licence since 1958 under my old call G3NIA and my New Zealand one for much longer. As A CW man I always regretted losing my UK callsign as it is a nice palindrome in Morse.
I spent several years in semiconductor research with TI in the UK, then came out to NZ in late 1964 and worked for Auckland university for 40 years.
My late uncle is to blame, when I was fiddling around with crystal sets in the early 50's he bought 4 NZ apple boxes full of NOS 1920's parts from an old garage business. It was like giving me a big electronic Meccano set!
As a result I have always been interested in early radio and while I was at University I studied towards a degree based on the history of technology.
Until recently I ran a small business in my retirement restoring old valve radios for museums and individuals. My biggest specialty was restoring old communications equipment which is where you probably found my posts. Just yesterday I came across a point about spark frequency, there seems to have been a lot of confusion at the time about whether the AC used was single or three phase. I tend towards the latter in land stations as some used only 150 Hz and a 300 Hz spark note would not match with the general 800Hz to 1.2 kHz range of Marconi and Telefunken equipment.
You probably know that the headphones were often set up for maximum response around there by adjusting the value of the bypass capacitor across the Phone terminals. Every bit of signal was precious!!! 3 phase would have given a 900 Hz spark rate, just where you wanted it to be.
Lee de Forrest may not have understood how his Audions worked, but we should be very grateful to him anyway.
Yes, BTW you are right about the UPS waveform the width of the peak made the spark easier to adjust, but it made damping more difficult as the peak lasted longer. However this was just a demonstration and fed into a carbon filament bulb dummy load.
Indeed you are VERY correct about Marconi copying Tesla's ideas for the "jigger", after all a Tesla coil is basically a spark transmitter with an enormous L/C ratio between primary and secondary and a high Q. The L/C ratios were amazing by modern standards. A primary coil working at ~30 Khz despite being very large might have only 4 turns even if over 2 metres in diameter, but then you had a very large air gapped capacitor to tune it. One of the biggest things I had to realise when building a spark transmitter was just how much this L/C ratio had to change from modern technology.

 

[Steven Christian]

Well Steven I've had my Ham licence since 1958 under my old call G3NIA and my New Zealand one for much longer. As A CW man I always regretted losing my UK callsign as it is a nice palindrome in Morse.
I spent several years in semiconductor research with TI in the UK, then came out to NZ in late 1964 and worked for Auckland university for 40 years.
My late uncle is to blame, when I was fiddling around with crystal sets in the early 50's he bought 4 NZ apple boxes full of NOS 1920's parts from an old garage business. It was like giving me a big electronic Meccano set!
As a result I have always been interested in early radio and while I was at University I studied towards a degree based on the history of technology.
Until recently I ran a small business in my retirement restoring old valve radios for museums and individuals. My biggest specialty was restoring old communications equipment which is where you probably found my posts. Just yesterday I came across a point about spark frequency, there seems to have been a lot of confusion at the time about whether the AC used was single or three phase. I tend towards the latter in land stations as some used only 150 Hz and a 300 Hz spark note would not match with the general 800Hz to 1.2 kHz range of Marconi and Telefunken equipment.
You probably know that the headphones were often set up for maximum response around there by adjusting the value of the bypass capacitor across the Phone terminals. Every bit of signal was precious!!! 3 phase would have given a 900 Hz spark rate, just where you wanted it to be.
Lee de Forrest may not have understood how his Audions worked, but we should be very grateful to him anyway.
Yes, BTW you are right about the UPS waveform the width of the peak made the spark easier to adjust, but it made damping more difficult as the peak lasted longer. However this was just a demonstration and fed into a carbon filament bulb dummy load.
Indeed you are VERY correct about Marconi copying Tesla's ideas for the "jigger", after all a Tesla coil is basically a spark transmitter with an enormous L/C ratio between primary and secondary and a high Q. The L/C ratios were amazing by modern standards. A primary coil working at ~30 Khz despite being very large might have only 4 turns even if over 2 metres in diameter, but then you had a very large air gapped capacitor to tune it. One of the biggest things I had to realise when building a spark transmitter was just how much this L/C ratio had to change from modern technology.

You got your ham license the year I was born. Which means you've seen the whole range of the progress of the technology. Most younger technicians probably wouldn't have a clue about half the stuff your era of tech's discuss or work on. Surface mount technology today is pretty much remove and replace. Not much troubleshooting/repair involved anymore. It's good to know there are people that can still restore some of the old radio's and such. I have two 1930's AM radio's that need to be restored. One of these days I will attempt to so. But my hobby is restoring old machines. That takes up most of time these days. One of the things that facinates me about Titanic is not just the ship but the era in which she existed. How people were able to design and figure out the technology they developed with just pencil and paper and maybe a slide rule. I admire those people. Cheers.