Do you have experience on connecting a Sub-1GHz transceiver to public TV antenna?

Dear RF Engineers and Applied Physicists,

What are your experiences on connecting a Sub-1GHz transceiver to a public TV antenna?

Since I live in a very dense city with skyscrapers, I cannot set up my own antenna outside my building. Then, I want to wire my own SMA Male to TV Male Plug coaxial cable. This will connect my Sub-1GHz transmitter directly to my building`s public TV antenna.

The next step is to connect my ISM band Sub-1GHz transmitter to test a receiver several hundred metres to 1km away.

Who have experience on this? What else should I do to improve the transmission or communication? I guess a high quality Element14 MultiComp coaxial cable can serve well.

Thanks for your opinions.

Top Replies

anniel747 10 months ago in reply to shabaz

In the city where signals are strong a simple passive multiway splitter can be used.
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HKPhysicist 10 months ago in reply to shabaz

Bad news. Public antenna is for receiving only.

Then, I have to set up my own antenna for testing.
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BigG 10 months ago in reply to HKPhysicist

An antenna doesn't care whether its transmitting or receiving. They're just a cleverly spaced strip of conductive material. Essentially, antennas are designed to operate at specific frequencies. This means the length of the antenna has to match the wavelength. So have you confirmed whether the TV antenna is suitably matched to your desired transmit/receive frequency. Otherwise you will struggle to achieve the desired transmit distances, no matter the power.
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HKPhysicist 10 months ago in reply to BigG

Nowadays, TV is UHF range (around 400Mz) with digital transmission.

My target wireless connection target is an ISM band at 920MHz.

That is why I want to use my building`s public antenna.
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BigG 10 months ago in reply to HKPhysicist

Unfortunately the antenna lengths required for the two frequencies aren't compatible - a 2cm difference is big for RF. According to omnicalculator.com dipole calculator (which gives a reasonable approximation and thus useful for comparison), the wavelengths don't match very well. As such it's unlikely to work at all, or at best you'll only achieve quite short TX distances.
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COMPACT 10 months ago

Make sure you’re adhering to the regulations to ensure the safety of yourself and others (even on the ISM bands).
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anneranch 10 months ago in reply to COMPACT

From the original description - you are building a repeater - receive a signal and re-transit it.

Hence you have to have means to "receive signal" via receiving antenna and then means to re-transmit the signal via

"transmit antenna". Both antennas must be designed for specific frequency and desired "directionality" etc.

The actual "repeater" hardware is your choice. In general RF output power in determining factor etc.
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