RSSI .DAT works?

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IK8JHL
Posts: 107
Joined: Tue Dec 10, 2019 11:19 am

RSSI .DAT works?

Post by IK8JHL » Sun Feb 16, 2020 3:36 pm

I wanted to know if OpenGD77 supports RSSI.dat and if there is a way to calibrate it. I tried to launch pistar-mmdvmcal but it doesn't support OpenGD77

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: RSSI .DAT works?

Post by VK3KYY » Sun Feb 16, 2020 8:20 pm

MMDVMCAL is not supported as there is no need for this to calibrate the radio.

The RSSI value is taken directly from the AT1846 RF IC, however the chip is not super accurate

IK8JHL
Posts: 107
Joined: Tue Dec 10, 2019 11:19 am

Re: RSSI .DAT works?

Post by IK8JHL » Mon Feb 17, 2020 11:55 am

VK3KYY wrote:
Sun Feb 16, 2020 8:20 pm
MMDVMCAL is not supported as there is no need for this to calibrate the radio.

The RSSI value is taken directly from the AT1846 RF IC, however the chip is not super accurate

So if I understand correctly, mmdvmhost doesn't use the rssi.dat file? Is the value I read in the Pi-star dashboard read directly from the GD-77?

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F1RMB
Posts: 2518
Joined: Sat Nov 16, 2019 5:42 am
Location: Grenoble, France

Re: RSSI .DAT works?

Post by F1RMB » Mon Feb 17, 2020 1:41 pm

Hi,
IK8JHL wrote:
Mon Feb 17, 2020 11:55 am
VK3KYY wrote:
Sun Feb 16, 2020 8:20 pm
MMDVMCAL is not supported as there is no need for this to calibrate the radio.

The RSSI value is taken directly from the AT1846 RF IC, however the chip is not super accurate

So if I understand correctly, mmdvmhost doesn't use the rssi.dat file? Is the value I read in the Pi-star dashboard read directly from the GD-77?
The default Pi-Star mapping file (RSSI.dat) just convert positive to negative RSSI values:

Code: Select all

# RSSI Default Values for MMDVM_HS
#
43           -43
53           -53
63           -63
73           -73
83           -83
93           -93
99           -99
105          -105
111          -111
117          -117
123          -123
129          -129
135          -135
141          -141

So, what you see in the Pi-Star (or a dashboard) it's the value reported by the GD itself, but switched from positive to negative by MMDVMHost, using the RSSI.dat file:

Code: Select all

M: 2020-02-17 13:41:55.221 DMR Slot 2, received RF voice header from F1RMB to 9990
M: 2020-02-17 13:42:01.156 DMR Slot 2, received RF end of voice transmission from F1RMB to 9990, 5.8 seconds, BER: 0.5%, RSSI: -70/-43/-69 dBm
Cheers.
---
Daniel

IK8JHL
Posts: 107
Joined: Tue Dec 10, 2019 11:19 am

Re: RSSI .DAT works?

Post by IK8JHL » Mon Feb 17, 2020 2:05 pm

OK, so the ratio is 1: 1 and there is no need calibration (about) but it only eliminates "negative", thanks for the answers

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