Modulation vs. Output Power

Products ePMP
1

What is the maximum power output for each modulation rate for the 2.4 GHz and 5 GHz ePMP radios?

The closest I've come to finding the information is In the "ePMP User Guide Release 2.4.2". Tables 87 and 88 (on pages 318 and 319) show output power as 23 dBm for every modulation, but the radio specs say up to 30 dBm.

Thanks - Chris

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2
@uberdome wrote:

What is the maximum power output for each modulation rate for the 2.4 GHz and 5 GHz ePMP radios?

The closest I've come to finding the information is In the "ePMP User Guide Release 2.4.2". Tables 87 and 88 (on pages 318 and 319) show output power as 23 dBm for every modulation, but the radio specs say up to 30 dBm.

Thanks - Chris

Chris,

See if the below table helps - We have 23dBm but in non FCC places it is higher and reflected on the table below.

Txpower.jpg

3
@Sakid Ahmed wrote:

See if the below table helps - We have 23dBm but in non FCC places it is higher

Sakid, 

To clarify, is 2.4 GHz output restricted below the chart you just shared (For the US)? Since 2.4 GHz is limited by the FCC to 30 dBm conducted power, 36 dBm total power, and has the +3 -1 rule for PTP, it would seem the connectorized versions should have no reductions while the integrated units should be limited to ~28 dBm (and neither should be limited to 23).

Thanks, 

Chris

4

Right, based on the antenna gain you input the radio will automatically reduce the Tx power to work within the regulatory boundaries. 

Let me check the PTP mode of operation for you.

Sakid

5

1>What is the maximum  RX power level before reciever saturation for the epmp1000 line?

2>What is the minimum SNR needed to mantain MCS15 Modulation? Is anything more than 30db necessary?

3>In Ealign tool, i see Ch0 = -48, Ch1 = -48 And RSSI = -42 .


>How does the aggregated power get to be +6db from the separate channels?

>>The textbook says that the best you can expect as the sum of two correlated channels is +3db from the >>base channels RSSI. What kind of black magic is going on there??

6
@Guilherme wrote:

1>What is the maximum  RX power level before reciever saturation for the epmp1000 line?
Our tests indicate we can handle as strong as a -25dBm Rx power level.
2>What is the minimum SNR needed to mantain MCS15 Modulation? Is anything more than 30db necessary?
The C/I required is 30dB or greater. Please note that this is Carrier to Interferer ratio as opposed to SNR which does not take into account specific interference sources.
3>In Ealign tool, i see Ch0 = -48, Ch1 = -48 And RSSI = -42 .


>How does the aggregated power get to be +6db from the separate channels?

>>The textbook says that the best you can expect as the sum of two correlated channels is +3db from the >>base channels RSSI. What kind of black magic is going on there??

Are you using 40MHz channel by any chance? In the case of 40MHz we actually have two additional extended chains from our driver that returns a value. This is not displayed today in eAlign or in the admin level of the CLI. However, at root level it returns the following  (Just an example)

 root@Cambium-Device:~# athstats ath0 | grep rssi
absolute rx rssi of channel [combined]: -60
rssi of last rcv[ctl, ch0]: -69
rssi of last rcv[ctl, ch1]: -64 
rssi of last rcv[ext, ch0]: -70 
rssi of last rcv[ext, ch1]: -64
This is the output from a 40Mhz channel

In this case, each RSSI level is first converted watts, summed up and then converted back to dBm to reflect the combined RSSI. 

Hope this helps.

Sakid

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7

Do you have this table updated to ePMP 3000?

Thanks

8

From our tests in the past (I keep a notebook), the 3000 will transmit at 29dbm all the way up to MCS9 in non-DFS bands, and 21dbm all the way to MCS9 for DFS band...if this helps you any.