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I am thinking about making an inexpensive LoRa geteway by combining eight single-channel RFM95W 915 MHz transceivers. These would just work as receivers, and I would have a 9th one working separately as a transmitter. The point is that these modules are available cheaply.

I am wondering if it's possible to connect all eight to a single antenna. The ninth (transmitter) would be on a separate antenna, so there would be two antennas. This question is similar but is concerned about MIMO, which is not the case for me. I have also seen this question, where a power divider is suggested.

However, I am not sure that a power divider is appropriate. I have not seen an eight-channel one in IC form. The first question I referenced mentioned doing a microstrip Wilkinson power divider, but I am not sure if this is feasible for 8 receivers.

Is what I am thinking about doing reasonable/feasible?

I also thought about just laying out nine PCB antennas or using 9 chip antennas. Would placing these side-by-side on the PCB be reasonable?

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    \$\begingroup\$ Antennas and circuits that connect to most antennas use impedance matching. Providing you match all the impedance you'll be ok even if the signal power to each receiver is highly diluted. \$\endgroup\$ – Andy aka Aug 14 '17 at 19:04
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    \$\begingroup\$ Why connect 8 receivers to one antenna, rather than sharing the output from one receiver? Knowing that might help steer solutions. Ditto knowing range, noise and power constraints might help \$\endgroup\$ – Brian Drummond Aug 14 '17 at 19:47
  • \$\begingroup\$ @BrianDrummond I am using multiple receivers because each one will be tuned to a different frequency/LoRa spreading factor. There are not really any requirements here, aside from trying to make this as inexpensive and easy to put together as possible. I believe that the maximum transmitted power for LoRa is +20 dBm in Canada where I live. \$\endgroup\$ – user21760 Aug 26 '17 at 14:20
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Using a Wilkinson divider will effect the sensitivity of your receivers by 9dB. you can add an LNA to compensate that.

If you use a narrowband chain you can match the receivers to the antenna, but I guess you want to use different frequency for each receiver, therefore a matching is difficult in that case.

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There are generally three solutions to this problem:

  1. A power divider - An ideal resistive power divider will give you 9 dB loss. Actual power divider will have losses closer to 12 dB. There are off the shelf connectorized products for this function.
  2. RF Multiplexer - Basically, only one receiver will be active at any given time.
  3. Use an antenna for each receiver (or group of receivers) to get both spatial and frequency diversity.
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