Talk:Orfordness transmitting station

How tall are the towers? When were they built?

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 * Corrected formatting/usage for http://blogs.rnw.nl/medianetwork/dutch-radio-1-to-start-using-648-khz-on-4-august

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Frequencies
I'm guessing it's no coincidence that of the frequencies chosen, one was exactly double the other. I presume this would have simplified the antenna arrangements, but it would be mice to have confirmation by somebody who knows what they're talking about. Lee M (talk) 01:48, 16 November 2017 (UTC)
 * It's just a coincidence. It made no difference to the antenna arrangements. Harumphy (talk) 22:36, 18 November 2017 (UTC)


 * It was very deliberate, no coincidence. It doesn't affect the antennae so much as the transmitter.
 * There was an operational need for transmitters on two frequencies, one approximately twice the other. If two large transmitters share a site and are closely spaced in frequency, there are all manner of interference problems. This is still the case when one frequency is close to a harmonic of the other. The easiest way to avoid this is to make the frequencies an exact multiple of each other, by running them all from the same master oscillator.
 * The antennae at Orfordness were separate though. Andy Dingley (talk) 23:22, 18 November 2017 (UTC)
 * Many AM broadcast sites run multiple transmitters (e.g. Droitwich 198, 693, 1089 and 1215 kHz), often with the output of two or more transmitters fed through a combining unit to a shared antenna. It's commonplace. The combining unit provides the necessary isolation between transmitters. At Orfordness, the wide separation between the two arrays provided isolation. If any more had been required, simple filters could have done the job. The reason that Orfordness used 648 and 1296 is that these were two of the high-power allotments to the UK following GE75. The rest (693, 810, 882, 909, 1053, 1089, 1152, 1215, 1458 IIRR) were used for domestic networks. It may have been that there was an operational need for frequencies at Orfordness at *approximately* these frequencies because of their propagation characteristics, but there was no need for an exact 2:1 ratio. That was a coincidence arising from the limited choice available from the GE75 allotment. Harumphy (talk) 12:00, 19 November 2017 (UTC)

Radio Caroline
Radio Caroline has commenced it's regular transmissions on 648 kHz, so the station is no longer out of service. The article should be revised. — Preceding unsigned comment added by Derasselner (talk • contribs) 10:42, 12 January 2018 (UTC)


 * It looked to me that the content was not incorrect but the headings were outdated so I changed them. Hope this is suitable Jiver2 (talk) 09:10, 20 May 2022 (UTC)