UHF signal strength

Irony of a thread being hijacked and the site of the hijacked device has been hijacked has not passed me by! :-) Brian

I blame these bloomin Internet plug adaptor things putting RF down the mains for trashing most devices like this, myself. Brian

Or less signal if its cross mod or overload. Brian

Thank you.

Bill

Yes, although with DTT, signal overload seems to be much less of a problem than it was with analogue. I cam hypothesise why.

Bill

I see you've failed to understand the situation. Mobile phone rf front ends are not busy receiving TV broadcast frequencies, so the phone is't going to measure them.

Nor can a 1GHz CPU process broadcast frequecies in the approximate region of 1GHz. Obviously it can process the lower frequency data that results when rf is demodulated, but since it's not receiving the TV broadcast frequencies there is no TV data to even look at.

NT

mobiles use signals on 800MHz frequencies previously occupied by TV, also mobile phones operate as SDRs, so if they *wanted* to the chipsets could potentially decode DVB-T ... but I wouldn't hold your breath.

ITYWF its 900 Mhz or 1.8Ghz.

In the UK

I dont think TV everr went that high

Those are the original GSM (and PCS) 2G frequencies, All the TV channel changes pre-DSO were about clearing 800Hz for 4G use.

They also started clearing the 700MHz block two years ago, hence more re-tunes

UHF68 about 850MHz

uhf channel 68 - the highest - was 847MHz

However the top of the uhf broadcast band has been taken for mobile prones

Ah. Post my time.

I meant as high as 900.

I thiubk sopme of my muxes are on 68...oh. no. they have moved them to

MMM.. 4G is quite powerful and so will a local phone be. Time for a sharp cutoff/notch filter methinks

Doesn't cross mod only happen with a busted receiver? It shouldn't be picking up anything other than the tuned channel.

And why would you get overload with just a plain aerial?

I'd guess a SS memory would push the price up too far at the moment. My recently bought Humax has 2Tb.

But if the noise is generated inside the TV receiver, or in the wire from aerial to TV, and you amplify the signal before that point, you improve the ratio?

Must cost a lot to put those things up there though. Not sure how much when compared with the income of the TV companies.

I usually see both readings on the Sky box go down if the cable is too long. Adding an inline amp somewhere along the cable helps - usually at the point where I think the signal is becoming weak - put it too early and you overload things.

How long are the cables, and what sort of cable?

Bill

Irrespective of the precise design of the front end, domestic receivers will always suffer cross-mod when a very strong signal is applied. Nothing is perfect, especially when built to a price.

There's also inter-mod. This rears its ugly head in a single channel amp that is overloaded.

Why not? If you're close enough the signal levels can easily be excessive.

Bill

Standard Sky cable, 200 metres.

I've never experienced that. Usually the problem is you're miles from the nearest transmitter, or there's something in the way (TM Nirvana). Mobile phones are absolutely terrible for this, presumably due to higher frequencies that don't travel so far or round corners so easily.

Pretty Astranomical .

I?ll get my coat.

GH