4G Interference to UHF DTV

dkreichen1968

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From The Article:
Last month I mentioned that I was seeing interference from my Verizon Samsung SCH-LC11 LTE 4G hot-spot in some USB ATSC receivers. During the past month I had a chance to look into this in more detail and capture some spectrum analyzer photos showing emissions from the hot-spot. I think I've identified the interference mechanism.

This month I'll look at the 700 MHz 4G spectrum allocations, how they are used by wireless carriers, and the potential impact of this use on DTV stations operating on higher UHF channels...

...More study is needed, but I don't think the Verizon Samsung hot-spot itself is to blame. The real cause of the interference is likely a lack of filtering in some ATSC USB tuners and the proximity of the 700 MHz device to the TV antenna. The fact that some newer receivers, like the Hauppauge Aero-M, perform much better supports this.

Set-top boxes might be less susceptible to this interference since they had to pass NTIA certification. Any tuner using a double conversion front end should be immune to the N+14 or N+15 interference. Manufacturers of ATSC MH receivers for tablets and smartphones will need to consider potential interference from 4G 700 MHz transmitters in these devices if the 700 MHz transmitter is not shut off while watching TV.
Read More: 4G Interference to UHF DTV, by Doug Lung
 
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