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OFCOM - SRD frequencies


paulears

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The details are now available Ofcom document.

 

Looks like those still using the remainder of the old radio mic UHF band have a few more potential problems, and those using old VHF radio mics also have some additions to the band occupancy.

Here's a summary of the new status

 

173.965 to 216 MHz for ALD Not currently exempt from licensing.

446.0 to 446.2 MHz for PMR446 Current exemption needs to be amended. - double the channels for analogue

863 to 865 MHz for Non-specific SRDs Already exempt from licensing.

863 to 868 MHz for Wideband data transmission devices Not currently exempt from licensing.

865 to 868 MHz for RFID devices Current exemption needs to be amended.

865 to 868 MHz for Non-specific SRDs Not currently exempt from licensing.

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So if I read this correctly, 863-865MHz (that we endearingly call channel 70, despite it being only 2MHz) can have a 25 mW e.r.p. transmitter sending out electricity meter readings in a venue, albeit only on a 0.1% duty cycle or a 'listen before talk' or 'adaptive frequency agility' system...

 

Sounds like a great way to get sporadic, hard to trace interference?!

 

 

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173.965 to 216 MHz for ALD Not currently exempt from licensing.

So in 173.965 to 216 MHz Assistive Listening Devices are now permitted. The bottom 1 and a bit MHz to 175MHz (centre) is overlapped with the license exempt radio microphone band, which has always been "buyer beware". Anyone paying for a license between 175.250 and 177.000 is presumably going to be more annoyed, but presumably there aren't many or there would have been some responses to the consultation! That said the determination requires protection of DAB reception (by a lockout threshold of 35 dBμV/m), which I would expect to also protect radio microphone systems which are likely to produce rather stronger signals?

 

Devices are required to tune the whole range allocated, so hopefully they can be coerced into using other parts of it when conflicts occur!

 

On a tuning range basis [25]. Channel spacing: max 50 kHz.

A threshold of 35 dBμV/m is required to ensure the protection of a DAB receiver located at 1,5 m from the ALD device, subject to DAB signal strength measurements taken around the ALD operating site. The ALD device should operate under all circumstances at least 300 kHz away from the channel edge of an occupied DAB channel.

Techniques to access spectrum and mitigate interference that provide at least equivalent performance to the techniques described in harmonised standards adopted under Directive 2014/53/EU must be used.

[25] Devices shall implement the whole frequency range on a tuning range basis.

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So if I read this correctly, 863-865MHz (that we endearingly call channel 70, despite it being only 2MHz) can have a 25 mW e.r.p. transmitter sending out electricity meter readings in a venue, albeit only on a 0.1% duty cycle or a 'listen before talk' or 'adaptive frequency agility' system...Sounds like a great way to get sporadic, hard to trace interference?!

I have basically stopped using VHF radio mics due to the increased data burst interference in the last 4 or 5 years particularly in hotels. I still use it for non PA applications such as IEMs and recently for the 'base transmit' for adding radio onto tecpro.

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