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Topic Title: At what frequency does RF Engineering start at?
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Created On: 06 March 2012 10:38 PM
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 06 March 2012 10:38 PM
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eswnl

Posts: 144
Joined: 29 November 2008

I wondered at what frequency does one start to enter the RF engineering realm. I've heard some people say quite high figures e.g. 100MHz. But surely, any sinusoidal wave of any frequency in a wire will cause it to radiate, so RF could cover all frequencies (except DC), which don't sound right.

Perhaps a more accurate explanation would be the lowest frequency of RF that can be efficiently utilized and transmitted in air?
 07 March 2012 08:33 AM
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ectophile

Posts: 540
Joined: 17 September 2001

BBC Radio 4 is still transmitting at 198kHz longwave.

The UK time signal (the one that was the Rugby time signal until they moved it) is at 60kHz.

According to Wikipedia, the US Seafarer system used to transmit to their submarines at 76Hz. Is that low enough?

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S P Barker BSc PhD MIET
 07 March 2012 10:18 AM
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rogerbryant

Posts: 864
Joined: 19 July 2002

High frequencies are not only used for radio transmission purposes. In my field of particle accelerators various high frequencies are used:

100kHz at a few hundred kW to feed a capacitive coupled voltage multiplier generating up to 5 MV and 50 mA.

100 MHz at a few hundred kW to feed a resonant cavity delivering electrons at up to 10 MV and 10s of mA.

1 - 10 GHz from kW to MW used to feed waveguides used for particle acceleration from a few MeV up to a few TeV (CERN).

These are all systems that are classes as RF or microwave engineering.

Best regards

Roger
 22 March 2012 10:02 PM
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davidwalker2

Posts: 189
Joined: 29 April 2009

Until it closed, the GBR transmitter at Rugby broadcast on 16 kHz. In the transmitter hall you could hear the transmission!
David
 23 March 2012 11:42 AM
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haguetim

Posts: 109
Joined: 25 April 2006

Have a look at this:-

Wonderful RF (and mechanical) engineering

http://en.wikipedia.org/wiki/Grimeton_VLF_transmitter

If this was the UK, they would have built a Tesco's on it...
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