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Terrestrial Broadcasting
Terrestrial Television, Digital and Analogue
Switch Mode Power Supply Woes - New Aerial/Mast head amplifier.
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<blockquote data-quote="jeallen01" data-source="post: 1057718" data-attributes="member: 176704"><p>Apart from the incorrect description, it is not quite true to say that "it's not supposed to emit any interference and is supposed to reject any interference".</p><p></p><p>There are no such "absolute" requirements but there are maximum "emission" limits and minimum "susceptibilty" (interference rejection) limits for equipment for domestic and commercial premises.</p><p></p><p>Both sets of limits are relatively low because those premises generally contain a lot of electrical & electronic equipment, but not much is very high powered/"noisey".</p><p></p><p>However, the emissions measurement process is generally done at 3m distance between the EUT and the measuring antenna, and that's a lot greater separation than is found between kit in most houses. So anything that is at/near the maximum emissions limits at 3m could well cause interference to stuff that is closer. Then again "some people" can be "generous" with what they accept/declare and certify<img src="http://www.satellites.co.uk/styles/default/xenforo/smilies/rolleyes.gif" class="smilie" loading="lazy" alt=":rolleyes:" title="Roll Eyes :rolleyes:" data-shortname=":rolleyes:" />.</p><p></p><p>PS: I got one of the very first Amstrad Sky Digital boxes in the Autumn of 1988, and that caused a lot of interference to the AV kit in the rack around it. Had to replace all the existing cables in/around the rack with decent double-screened coax to suppress the interference (and been doing the same ever since with little or no interference issues - except some audio hum on the Phono i/p from the combined effects of quite a few Class II Double insulated PSUs, but fixed that with a wire from the AV amp to the Earth of the incoming supply to the rack).</p></blockquote><p></p>
[QUOTE="jeallen01, post: 1057718, member: 176704"] Apart from the incorrect description, it is not quite true to say that "it's not supposed to emit any interference and is supposed to reject any interference". There are no such "absolute" requirements but there are maximum "emission" limits and minimum "susceptibilty" (interference rejection) limits for equipment for domestic and commercial premises. Both sets of limits are relatively low because those premises generally contain a lot of electrical & electronic equipment, but not much is very high powered/"noisey". However, the emissions measurement process is generally done at 3m distance between the EUT and the measuring antenna, and that's a lot greater separation than is found between kit in most houses. So anything that is at/near the maximum emissions limits at 3m could well cause interference to stuff that is closer. Then again "some people" can be "generous" with what they accept/declare and certify:rolleyes:. PS: I got one of the very first Amstrad Sky Digital boxes in the Autumn of 1988, and that caused a lot of interference to the AV kit in the rack around it. Had to replace all the existing cables in/around the rack with decent double-screened coax to suppress the interference (and been doing the same ever since with little or no interference issues - except some audio hum on the Phono i/p from the combined effects of quite a few Class II Double insulated PSUs, but fixed that with a wire from the AV amp to the Earth of the incoming supply to the rack). [/QUOTE]
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Terrestrial Broadcasting
Terrestrial Television, Digital and Analogue
Switch Mode Power Supply Woes - New Aerial/Mast head amplifier.
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