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I'd like to know if two endpoints in an RF communication system can have different types of antennas, like one directional (yagi) and the other omnidirectional (dipole).

I want to do this because I have an object that I'd like to have RF communication with. I don't know the exact orientation that this object will be in, but I would know its location relative to where I'd be communicating with it (ground station). Is it a good idea to use an omnidirectional antenna for the object, so that it can send/receive signals from all directions, and for the ground station to have a directional antenna pointed at the object? Would this work better than having two omnidirectional antennas at both ends?

Also, just in case this is relevant, the pair of RF modules communicating with each other are gonna be 900MHz Xbee XBP9B-DMST-002.

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  • \$\begingroup\$ RF does have both omnidirectional and focused antenas, though they aren't antennas, so much as constructs. (filters, focuses, etc) \$\endgroup\$ – user86234 Aug 3 '16 at 18:52
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A directional antenna is always preferable to omnidirectional. Both for transmitting and for receiving. But, as you say there may be factors that preclude using a directional antenna. For example, for portable (especially hand-held) use, a directional antenna may be to unwieldy, so a whip or "rubber duckie" antenna is typically used. Or if you don't know the direction of the communication, a directional antenna can be a liability.

If your mobile end knows what direction the fixed location end is, then you would benefit from at least using a directional antenna where you KNOW the direction.

A directional or omnidirectional antenna can be used with any type of antenna at the other end. Some VHF and UHF communication use polarization where the receiving antenna should be using the same polarization (vertical, horizontal) as the transmitting antenna

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    \$\begingroup\$ Important to note that right & left hand circularly polarized antennas are not compatible. Either circular with a linear antenna will work, but there will be ~3dB of polarization mismatch. Lastly, linear polarized antennas need to be aligned parallel to each other (or close) to be effective. \$\endgroup\$ – Andrew W. Aug 3 '16 at 21:05

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