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Anubis
Antenna-Theory.com Newbie
Joined: 08 Oct 2015
Posts: 1
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 Posted: Thu Oct 08, 2015 1:11 pm Post subject: Active ans passive GPS antennas |
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Hi all,
I have a question concerning active and passive GPS antennas. A passive GPS antenna contains only a patch antenna whereas an active one also adds an integrated LNA + filters.
Generally, for active antennas, the DC supply needed for the LNA comes directly from the SMA cable. My question is : if there is no DC supply whatsoever intended for the active antenna, does it behave as a passive antenna or not ? I mean, will the active antenna still work without any DC supply ?
Thanks for any answers.
Anubis |
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admin
Site Admin
Joined: 03 Jan 2007
Posts: 247
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| Posted: Thu Oct 08, 2015 5:48 pm Post subject: |
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| It *might*. It depends on the insertion loss of the LNA in the GPS band when the LNA is not powered. It may be noticeably worse (or they may install a switch that connects the LNA only when power exists). |
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helix
Antenna Theory Regular
Joined: 29 Jan 2015
Posts: 64
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| Posted: Wed Oct 14, 2015 2:46 pm Post subject: |
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| I'd guess that most active GPS antennas are terrible when they're unpowered. |
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