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Help to build: bi-directional 870MHz amp

rexys

Sep 22, 2014
2
Joined
Sep 22, 2014
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Hi, I'm trying to build a simple antenna amplifier for 870 MHz. It must be connected to a home automation systems that both send and receive at the same antenna (870MHz) Can anyone help me closer to a diagram of one of these?
Have lots of experience building electronics.

It should preferably use 24VDC

Kind Regards
 
Last edited:

rexys

Sep 22, 2014
2
Joined
Sep 22, 2014
Messages
2
Thanks for the reply , but that's not what I'm looking for.

It is an existing facility where the signal is not strong enough , therefore I seek an amplifier .
 

Fish4Fun

So long, and Thanks for all the Fish!
Aug 27, 2013
481
Joined
Aug 27, 2013
Messages
481
rexys,

Again, RF is not really in my wheelhouse, but if you are in the US (or any number of other countries), you might want to check the restrictions with-respect-to allowable power....If there are any other devices in the vicinity that utilize the 800Mhz band you might want to make certain you won't create more problems than you resolve by "boosting" the power of the transmitters in this particular device....As a final note, many "low power devices" are internally adjustable to meet the regulations of the various countries in which they might be marketed and frequently the output can be "boosted" without the addition of any external components either through firmware or via jumpers or potentially even a trimmer pot.....a great example is the WRTG series wireless routers which were constantly hacked ~ a decade ago in an effort to increase their range...The problem was that while the transmitter in the WRTG could be boosted considerably, there was no good way to "boost the transmitter" in the various wireless devices that were attempting to establish a link with it.....Anyway, I can't think of any "easy way to add an amplifier" between an RF device and it's antenna....but there are plenty of amplifier ICs available capable of operation in the 800Mhz-1Ghz band.....If this project is critical and NOT budget sensitive then you might consider simply placing a "repeater" midway between the devices....Such a device would "receive" a signal from one transmitter and then "re-transmit" it.....but such a project would NOT be trivial and would require detailed knowledge about the communications protocols and packet lengths.....

Perhaps a detailed description of the existing system and the functions it performs might provide alternative suggestions about the best way to solve the problem.....For instance, it might be possible to use a common consumer "IR to RF to IR" repeater typically used for controlling an IR device with an IR remote on the other side of the house via an RF signal.....but without knowing what you are attempting to achieve it is hard to guess a viable solution....

Here is a link to some examples of short-range bands...you can follow the footnotes for more details... http://en.wikipedia.org/wiki/Short_Range_Devices

Good Luck!

FIsh
 
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