Channel 70 amplifiers and LTE - studies at OFCOM

[alangeering]

The results of the studies into LTE (mobile broadband in the 800 MHz band) interference to DTV signals have been published and widely commented on.

 

These papers may have some relevence to radio microphone users in channel 70 as they deal with the problem of DTV distribution amplifiers - which are not so different to radio mic distribution amps.

 

The study was into the lower end of the band (Ch60/61 boundry) not the upper end (channel 69/70 boundry) but the results are worth reading.

 

MitCo - and independant body funded by the LTE using mobile companies - exists to provide mitigation to affected areas (e.g. by installing filters that block out the LTE range and above).

 

Does anyone know of a comparable study into Ch 70 interference and whether affected users can apply to MitCo for help?

 

This is mostly of interest to people will small setups (i.e. 4 channel 70 mics with remote antennas and amplifiers)

 

Basic:

http://www.bbc.co.uk/news/technology-17125468

 

Detailed:

http://stakeholders.ofcom.org.uk/binaries/consultations/949731/annexes/era.pdf

 

Given we've currently got Sennheiser E-Band signal boosters for our Ch70 equipment I'm interested in this topic.

 

Note: I'm not talking about Ch 69 to Ch 38 which has been covered many times over in the past. This is of interest only to people using Ch 70 - the unlicensed band.

[PJG]

I toyed with the idea of just buying 2 or 4 sets to use inchannel 70 rather than buy channel 38 and while talking over a different issuewith the manufacture they advised against buying into channel 70 as they couldnot say for curtain if it would work once channel 69 started to be re used andthat computer models will not predict what will happen. So I purchased channel38 kit.

 

 

[alangeering]

Effects of LTE on radio microphone systems were covered in the following:

http://stakeholders.ofcom.org.uk/binaries/consultations/tlc/annexes/Wireless_Audio_Testing.pdf

 

Unfortunatly the above study didn't cover anttenna bosters/amps/distribution equipment (in the way the new DTV study does).

 

Also note: DTV will be more affected by LTE downlink and thus proximity to a cell tower. Radio mic systems will also be affected by proximity to LTE phone handsets (uplink frequencies that go to 862 MHz).

 

 

We've also gone down the route of buying Ch 38 equipment but can't afford to replace all our Ch 70 equipment - also it's of interested to smaller venues who don't want to pay for a license.

[paulears]

Interesting reading. The conclusion seems to be that for TV, filtering does seem reasonably effective. For radio mics in channel 70, the biggest snag seems to be for those with no external aerial facility - meaning no possibility of filtering - so this could be 'interesting' for the cheaper brands. I suppose it's wait and see, because in a licence free band, there's no protection at all.