Watching the Eddie Izzard film on the development of radar, I was surprised that they used 'megahertz' rather than 'megacycle'. Was this usage accurate for the period?
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5 years ago
cycles to hertz - when?
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5 years ago
Nope, they stuffed that detail up.
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5 years ago
No - I don't know exactly when things changed, but I think the change was gradual between 1960 and 1970.
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5 years ago
It's Megacycles per second anyway - mc is meanlingless without a time element. On SW radio in the 60's it was mainly wavelengths in metres that was used, then Mc/s and Kc/s and then kiloHertz and MegaHertz came in more and more during the 1970's.
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5 years ago
Not really. It was cycles when I was young. However to be honest it was probably done for the modern person who had never heard of cycles. I suppose its a good job that the scientist was not called humperdink. Brian
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5 years ago
One thing that has always interested me is the fact that many shortwave stations even today, give the frequencies in Khz, but the band in metres. Now I used to know the conversion by heart when I could see, but over the years its kind of faded, but I know it contains the speed of light in metres per second. I often wonder why we have still got the two. Metres is of course very handy if you want to make your own aerial, but then you have this adjustment for the velocity factor for conductors.
However I notice that when you get to really high frequencies they are termed milimetric wavelengths. By the time the wavelength nears that of light we use other terms to describe the frequency. Basically though the energy received at a point in a given time period has to be greater the higher the frequency.
The wave particle duality still makes radiation of photons very interesting to me. One of the reasons I still tune the short wave bands even though in most cases I could get the same thing on the internet is that it means that a certain set of photons travels over a very random route from the transmitting aerial to mine. Oh and as somebody why has experienced an RF burn. touching a transmitting aerial is definitely not a good thing to do. Brian
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5 years ago
Brian Gaff presented the following explanation :
metres = 299792.458/ kHz
kHz = 299792.458/ metres
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5 years ago
That is strictly true of course, but the common parlance was megacycles and kilocycles. Like we use kilos for kilogrammes and mils for millilitres or millimetres depending on context.
Cheers
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5 years ago
I thought it was 300,000. The teaching at my school must have been a bit rubbish!
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5 years ago
Fings are more akrut now
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5 years ago
50Hum describes mains hum very accuratly!
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5 years ago
It's c/s not cycles. (cycles per second) If you leave the time element out, it's meaningless.
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5 years ago
...in a vacuum. I await with interest the essay on the conversion factor for BBC long wave from Droitwich :)
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5 years ago
Or even this chap:
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5 years ago
Trump is a MKundt!
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5 years ago
Although that is true back in the day the "in one second" was implied.
Radio and LF radar tended to use frequency but HF radar more often used wavelength.
Adopted by IEEE in 1965 and by Hewlett-Packard soon after - cutting from their house journal:
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5 years ago
The physics master at my (Catholic) grammar school always referred to it as "That tube".
Another Dave
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5 years ago
It never changed for me ......
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5 years ago
It could easily have been a Rutherford. He was an early pioneer of radio transmission and receiving but was persuaded that it would never amount to much and Marconi was to his disappointment was slightly ahead.
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Instead he went on to investigate the new field of radioactivity for which research he is much more famous.
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5 years ago
I always think of this story (perfectly true; I was part of the conversation).
I know the Darwin family quite well because one of the University of Kent Colleges is named after Charles Darwin. I was talking to the oldest member of the family a few years ago, and he was saying that he actually felt an affinity with three of the Colleges - Darwin, Keynes and Eliot.
I knew about the Darwin family being closely connected with, and intermarrying with, the Keynes family (which I also know, because of that). So I asked him why he felt an affinity with Rutherford.
"Oh", said he. "Ernest was my godfather".