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I am building a HAM radio. Do I need a separate antenna for transmitter and receiver?

I will be using 20m band and voice communication (No Morse code). My primary requirement is that I should be able to listen to and talk at the same time.

Also, since I am completely new to this area, how complex can the scheme of sharing the antenna can get? In other words, which would be simpler to implement: A shared antenna or separate antenna?

(I have decided to go with the inverted V antenna)

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    \$\begingroup\$ Don't you need a license to operate the equipment? The point being that anyone obtaining a license would become knowledgeable enough to know the answers you seek. That's the whole point about becoming licensed I thought but maybe times have changed? \$\endgroup\$ – Andy aka Jun 30 '14 at 10:41
  • \$\begingroup\$ FWIW: ham.stackexchange.com \$\endgroup\$ – Alfred Centauri Jun 30 '14 at 11:32
  • \$\begingroup\$ Actually i will apply for license. But being an electronics student, i am much more interested in building the set first. \$\endgroup\$ – Plutonium smuggler Jun 30 '14 at 12:50
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No, you can't listen and talk at the same time. Ham radio is not like using a telephone. The input of the receiver can't handle the power output of the transmitter.

If you have separate receiver and transmitter units, you'll need separate antennas, or some means of switching one antenna between the two units. If you have a transceiver, this mechanism is already built into the equipment.

"Some means of switching" could be as simple as a manually-operated switch or relay, but more commonly, you have a control signal from the transmitter that's driven by the PTT (push-to-talk) button that operates a relay automatically.

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  • \$\begingroup\$ Do you mean even by using separate antennas for both, i can't talk and listen simultaneously ? \$\endgroup\$ – Plutonium smuggler Jun 30 '14 at 12:47
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    \$\begingroup\$ Well, you might be able to listen, but all you'll hear is the output of your own transmitter. Full-duplex radio systems, like analog cellphones, operate at VHF or higher, and use separate frequencies for transmitting and receiving. They use special filters (a "diplexer") to make sure that the transmitter power doesn't overwhelm the receiver's input. \$\endgroup\$ – Dave Tweed Jun 30 '14 at 13:01
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In order to be authorized to build an amateur radio transmitter one has to be a licensed amateur with sufficient privileges to be legally able to do so. This might also involve a proficiency in sending and receiving morse code up to 12 words per minute. Merely being an applicant doesn't cut it. There is an exam to take. You have know radio design theory and possess knowledge of all regulations pursuant to radio. Failure to do will result in fines from FCC in the states and Industry Canada in Canada depending where you live.

The transmitter has to be spectrumly pure (so as to not cause interference) to comply with federal and international regulation. As for antenna system the same antenna can be used for both transmitting or receiving.

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