Open challange target

Dear Friends......

Really new Idea with new challange,

If anybody can design a device or system which putting next to TV o outside the TV box near the tuner section can detect which frequency i selected or which channel is selected.

You can use anything like RF, Ultrasonic, or any idea u want, just yo can't connect anything physically to the tuner.

Enjoy designing

Pankaj Bhimani

Really old idea that's been implemented in roaming trucks for at least three decades. Yawn.

Detect the frequency of the local oscillator, which as somebody else has mentioned has been used in the UK for decades. The real challenge would be to use ultrasonic to do it.

Peter

And what if you dont't know whether the tuner uses up or down conversion and it's MF?

Meindert

There have been detector vans in the UK for TV licence enforcement for some 50 years. The latest ones are described here :

This is hardly a new idea.

Ian

Pankaj, you forgot to set a prize, and a scheme on how it is divided.

Rene

While non-standard IF frequencies and local oscillators can be used to fool e.g. radar detector detectors, it would be quite problematic to implement on a TV receiver.

I have never seen a TV-tuner that would do upconversion. Upconversion is mainly used in HF general conversion receiver with the first IF in the 40-90 MHz range or in spectrum analyzers with the first IF at 2-4 GHz.

The TV IF is in the 30-40 MHz area for historical reasons and since SAW filters are used these days, it would be quite hard to do some special arrangements.

To cover the Band I VHF channels in the 47-68 MHz area, the local oscillator (LO) would have to be above the received channel (Rx) to keep the local oscillator tuning range reasonable. Running the LO below the Rx frequency also creates the problem of LO harmonics hitting the received channel. When the LO is above the Rx frequency, the harmonics can never hit the received frequency.

Anyway, since the LO must be above RF on Band I, the IF spectrum is inverted, moving the sound carrier from the top end of the channel to the bottom of the IF passband. Sound traps etc must be set at this frequency.

While it would technically be possible to put the LO below Rx on VHF band III and UHF IV/V, this would also require moving the IF sound trap to the opposite end of the IF-passband for these channels.

Thus, the LO is above Rx also on these channels to avoid this inconvenience.

Paul

Does tha mean the UPSO would patent it?

martin

This sounds Orwellian, or at the least very creepy. Do you see the movie "Brazil"?

"Brazil"?

Actually, the most likely current application of such a circuit is to make an ATSC converter for an analog television. Analog TV in the USA is going to be shut down after 2009, and there are going to be a lot of TVs that need a ATSC digital to analog converter, which the government is going to subsidize. Having the box be able to select its own channel adds cost to the converter and makes it less convienent, because it disables your old remote. If the converter can detect what channel the TV is tuning, it can "follow" the channel, and thus be a true black box with no need to directly control it.

shut

digital

Everybody uses cable boxes anyway. Just output the analog data on channel

Guys thanx very much for lots of reply

and thanx to all who instead of finding solution trying to proov themselve the tech geeks

But the overall challange is I dont want to open the TV box and using an wireless sensors i want to finish the task.

whtever channel is selected by pressing keys from remote then the tune will allow that RF I want to detect without opening the box or withou connecting a single wire to TV .

Thats all

has

would be

and

In that case, your best bet might very well be to listen in on the TV's remote. Universal replacement remotes demonstrate this is viable.

shut

digital

box

Sorry about the late response, but I only recently found out about this:

Apparently, 21 million households don't use either satellite or cable. The house allocated $1.5 billion in one bill that passed one legislative hurdle recently, to provide up to two $40 vouchers for each family in that group -- excludes anyone with cable or satellite, I think.

Jon