Author Topic: OPTIMUM SENSITIVITY SETTING FOR RX?  (Read 636 times)

evh

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OPTIMUM SENSITIVITY SETTING FOR RX?
« on: May 12, 2015, 07:15:20 PM »

I am deploying 915Mhz HWs at 1200Baud.   It seems like I never get an RSSI that is weaker than about 90db.   I am hoping to receive packets that are down to 120db.  Is there a setting I should use to get maximum sensitivity?  I noticed one -90 setting for CMSA or some such thing in the .h file.  I changed that to 119, but it did not seem to have any effect.

Thanks for whatever you can tell me.

Felix

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Re: OPTIMUM SENSITIVITY SETTING FOR RX?
« Reply #1 on: May 13, 2015, 10:51:53 AM »
I am deploying 915Mhz HWs at 1200Baud.   It seems like I never get an RSSI that is weaker than about 90db.   I am hoping to receive packets that are down to 120db.  Is there a setting I should use to get maximum sensitivity?  I noticed one -90 setting for CMSA or some such thing in the .h file.  I changed that to 119, but it did not seem to have any effect.

You mean weaker stronger than -90dbm?
To change the RSSI threshold look for this line - note there is a formula involved, you might want to check the datasheet for more details:

Code: [Select]
/* 0x29 */ { REG_RSSITHRESH, 220 }, // must be set to dBm = (-Sensitivity / 2), default is 0xE4 = 228 so -114dBm