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nRF52832 antenna signal "tolerances" for strong periodical nearby signals?

Good afternoon!

We're considering an off-the-shelf nRF52832 based device for our needs.

 the application will likely involve two nRF5283-based devices fitted with external antenna with >3 dbi gain, which is supported and supplied by the same people making the device itself.

One unit TX 

One unit RX

Both communicating to a remote device located relatively far and obstructed by concrete (hence the antenna. Preliminary testing shows that the signal strength / receive gain obtained are enough to ensure "good enough" communication between the "big antenna couple of devices" and the remote unit)

problem:

The "big antenna TX" unit is, and has to be, very near to the big antenna RX unit (<5 cm distance)

The TX broadcasts at maximum power, and is independent "doing its own thing" at its own pace.

Preliminary testing done by the module / antenna supplier show that nothing immediately untoward happens when the "receiver unit" is put in "radio disable" state for the period while "high strength broadcaster" is broadcasting stuff (which, given the closeness, is achieved via a wire to send "warning" via GPIO)

The seems okay (we don't need "true" async comms so receiver going to radio disable when the independent transmitter blasts its signal is acceptable, the timings between radio-disable and rx-enable also are fine as per prelim tests).

However, the supplier can't assure us that no long-term issues will arise due to regular exposure of receiver to comparatively uncommon high signal levels (albeit in radio-disable state).

What's the Nordic specialist opinion on this? Should we be concerned about some kind of weird long-term receiver unit degradation issues ?

P.S.:

the nRF52832 boards in question are supplied with ample power, but the solution is supposed to be "place and forget" so minimizing maintenance frequency is a concern.

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  • The radio frond end is designed to handle 10 dBm on the antenna pin without physical damage. There will be some loss between the two antennas so the actual level on the receiver antenna pin will of course be lower than the transmit power of the other transmitter. So unless you have a PA in your system, there's no risk of permanent damage.

  • Thanks!

    So hard limit is 10dBm.

    Good, but, given that both receiver and transmitter have those +3 dBm antennas and maximum power for TX is stated to be 6dBm in the datasheet, wouldn't that end up at possibly very close to the 10 dBm limit on the RX side (not sure what losses are for ~5cm of distance but probably not very much)?

    does the 10 dBm limit apply only if the receiver's radio is in RX state, or is it more of a "raw electrical thing" that can possibly fry the device even if it is in "radio disable" state?  

    P.S.:

    I'll see if our TX can "punch through" at lower transmit power, just in case.

Reply
  • Thanks!

    So hard limit is 10dBm.

    Good, but, given that both receiver and transmitter have those +3 dBm antennas and maximum power for TX is stated to be 6dBm in the datasheet, wouldn't that end up at possibly very close to the 10 dBm limit on the RX side (not sure what losses are for ~5cm of distance but probably not very much)?

    does the 10 dBm limit apply only if the receiver's radio is in RX state, or is it more of a "raw electrical thing" that can possibly fry the device even if it is in "radio disable" state?  

    P.S.:

    I'll see if our TX can "punch through" at lower transmit power, just in case.

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