Wireless Sound Question

[Matt Pereira]

I have a question that I cant remember the answer to and Ive searched for a few mins with no luck for the answer on here.

I am looking for what Hz Titanic`s wireless system operated on as in the signal output that other ships would have heard. I thought it was 50 or 60 but when I tried it in this one program at 50 or 60 it doesnt sound "musical" to me as described. Then on Parks website it says 500KHz which I figure to be 500,000 Hz but the program wont allow more than 50,000 Hz but at 50,000 Hz it does have a musical sound to it.

Just wondering what the actual Hz is for the output so I can try it in this program. Would really like to see how the wireless could have sounded like.

 

[Russell Friesen]

Hi Matt, Bruce Beveridge's "Titanic: The Ship Magnificent Volume 1" contains a chapter on the Marconi apparatus, and states that the spark frequency depended on the rotation speed of the disc discharger, and that if the disc rotated at 2100 RPM, this would produce a spark frequency of 560 Hz, a frequency that could be considered "musical". Try 560 Hz and see how that sounds.

 

[Matt Pereira]

Not to get off topic but is his book worth the price? Last I checked it was around $50 or $60 on amazon and I at the time couldnt justify the cost.

On the 560 Hz I have to say it sounds pretty nice better than what I thought I heard which was like 50 - 60 Hz which was a very deep sound.

This is the program im using though its free and I only recently came across it and thought if I could find an accurate frequency might for the first time get an idea of how Titanic`s wireless might have sounded to someone listening. Already heard what the whistle sounds like.

http://morsecode.scphillips.com/jtranslator.html

 

[Russell Friesen]

Hi Matt, I checked out the link you provided and it is interesting. I am under the impression, however, that Titanic's wireless didn't sound like the clean sine wave tone that this program produces. As the transmitter worked by producing a large electrical spark, which was received elsewhere the same way you can hear static or lightning noise in an AM radio, the signal would have sounded more like a static electricity "buzz" rather than a clean tone. The buzz would have been a 560 Hz buzz, but it would have been a buzz nonetheless. Maybe someone else can confirm or deny this for me.

As for the Bruce Beveridge books being worth the price, it depends what you are looking for. The two books are huge, heavy books with details about practically every detail and fitting that went into Titanic, but they are reference books and not something that most people would be able to sit down and read from cover to cover. That being said, books of that size with that amount of detail in them selling for around $50 each are a bargain if they are something that you would refer to on a semi-regular basis and find interesting. I got mine from Amazon also; the books will cost more anywhere else.

Hope that helps!

 

[Matt Pereira]

It sure does help and I figured it would have more of an "electric" sound to it than a "beep" sound I was just looking for the pitch you could say to get an idea of what the spark could have sound like.

On the book sounds good, I am more into the Titanic from a mechanical stand point than anything else. One of the things I would love to do is build a 1/6 scale model of the engine room and turbine room with 1/6 scale steam engines that will work off compressed air. But cost of something like that is too high. Guy on youtube built a triple expansion steam engine said it was around 1000 pounds to make.

So in the end on the book anything that has to do with the layout and or operation of the ship would be something I would be interested in. Might one day help with the construction of a super detailed cutaway model.

 

[Robert T. Paige]

Is the sound of the Titanic's signals heard in "A Night To Remember" authentic ? There was another movie...I think it was about the Britannic ?...in which the sound was depicted as modern CW type signal, which I believe would be erroneous ? I have heard the regular spark signals sounded rather raspy except for the Titanic's which used the rotary spark gap and sounded more musical ?

Were all detectors driven by a spring wound motor that had to be continually rewound from time to time or were there any using...say an electric motor that would run continuously ? "Winding the detector" seems to be a staple item in the Titanic movies ?

Were there any "auto alarm" circuits on the wireless that would sound an alarm bell when a distress signal was received ? It seems to me this would be a bit challenging technology for the time and would rely on the detector being active all the time ?

Incidentally on receiving code on a modern radio you can adjust the tone to any frequency of your liking.Usually the 400-500 HZ (audio) range is preferred.Some like 1000 HZ, etc. ....

Just a little humorous note : On a Single Sideband (SSB)voice signal you can adjust the received voice to sound like a basso profundo or a soprano just as you can adjust the audio tone up or down frequency on a code (CW) signal. LOL.

 

[Robert T. Paige]

>>Then on Parks website it says 500KHz which I figure to be 500,000 Hz but the program wont allow more than 50,000 Hz but at 50,000 Hz it does have a musical sound to it.<<

"HZ", which stands for "Herz" and is named for an early pioneer , is a new term for the old "Cycles Per Second". 500,000 HZ or 500 KHZ (KiloHerz) refers to the radio frequency to which the the transmitter or receiver is tuned. (Which of course is inaudible to the human ear.) The old term was 500 KC (Kilocycles.)

500 HZ refers to the audio tone or the one which you will hear in your headphones. The old term was 500 Cycles Per Second (CPS).

"Middle C" on a musical instrument is an audio tone about 440 HZ or the tone that you would hear from a tuning fork. The hum you hear on an old radio is most likely 60 HZ or 120 HZ.

The detector on a radio receiver separates the audio frequency ("AF")tone from the radio frequency ("RF")transmission.

PS- About that question about "winding the detector" It would seem that this would be one of "the weakest links of the Marconi system" in that it wasn't always listening. Nowadays certain frequencies are reserved for emergency transmissions and transmitters and receivers are always tuned and ready for instant use in an emergency. Of course in the days of spark transmissions there were very few frequencies in use and those that were were used for both emergency and normal traffic.

 

[Robert T. Paige]

Another question although this subject has been inactive for some time.
How broad were those spark transmissions ?
In other words, how much of the spectrum did they take up ?
Has anyone ever determined this ?

 

[Alex F]

,

Another question although this subject has been inactive for some time.
How broad were those spark transmissions ?
In other words, how much of the spectrum did they take up ?
Has anyone ever determined this ?

You can determine this yourself.

As per Berlin Wireless Convention, 1906:

Each Government may, however, authorize in coastal stations the employment of other wave lengths designed to insure long-range service or any service other than for general public correspondence established in conformity with the provisions of the Convention, provided such wave lengths do not exceed 600 meters or that they do exceed 1,600 meters.?

1600 - 600 = 1000 m

300 000 km/s /1000 m = 300 kHz

300/2 = 150 kHz (two sides from center of the band), or 3 times of standard deviation (from the best case)

150/3 = 50 kHz. (in the best case)

BR
Alex

 

[AlexP]

The Titanic had both High Frequency and low Frequency ability. Do we know which one was used for their communications during the night before and after the collision?

 

[Samuel Halpern]

Titanic was transmitting on a wavelength of 600 meters (500 kHz frequency)

 

[Robert T. Paige]

Were there any other frequencies/wavelengths that Titanic could operate ?
I my have read somewhere that operation could be on 600M/500 KHZ or 300M/1000KHZ (1MHZ) ?

I don't know how it is now, but when I was in the Navy one transmitter and one receiver and one transmitter were always reserved for emergency frequency/wavelength of 500KHZ/600M and always tuned and ready for use only on that one emergency frequency of 500KHZ.

The other transmitters and receivers could be tuned on any frequency as needed within their capabilities .

Amateur radio operators were limited to wavelengths of 200 Meters or less.
" 200 Meters And Down " by Clinton B. DeSoto is a book on early amateur radio on " short wave " .
Present bands are bands of 160 Meters....."and down ".....such as 80, 40, 20......etc.
There are also wavelengths of 2200 Meters and 630 Meters available under certain conditions.

 

[AlexP]

Titanic was transmitting on a wavelength of 600 meters (500 kHz frequency)

Thanks.
Do you know if they used the same frequency before the collision?

 

[Robert T. Paige]

Another rather ridiculous item in that " Britannic " movie was that the " spy" was using what apparently was a transmitter and receiver concealed in a book and used a wire antenna which he laid on a bench on the ship for operation.
Evidently the makers of that movie were not aware that miniaturization with transistors had not been invented in 1912 .
The only " Wireless " of that era took up a bit of space on board and used long and high antennas.

 

[Robert T. Paige]

Alex P-

I have always assumed there was no change in frequency ? 500 KHZ ?
I am sure you are aware of it but " Wireless" radio contacts such as on Titanic were always what we " hams " would call " simplex " operation .
That is, the transmitter and receiver were both tuned to the same frequency.
" Duplex" would be if receiving and transmitter frequencies were different.
For example ham radio repeaters stations on the 2 Meter ham band are offset by 600 KHZ
Your station transmits on 146.280 MHZ and receives on 146.880 MHZ.
The repeater station receives on 146.280 MHZ and transmits on 146.880 MHZ.
The ham rig automatically switches the frequencies.
This is a bit off topic, but I just wanted to make it clear that operations for both transmitting and receiving were on the same frequency in 1912

Anyone have a better answer ?
Mister Samuel Halpern ?
I have also heard they could also operate on 300 Meters , but most traffic was on 600 Meters ?
Any information on what and why on the differences ?


Robert