# RFX-2400 Max. Tx and Rx power

This one’s most likely for Matt:

I would like to connect the RFX-2400 Tx/Rx and Rx ports via coax and
some attenuators. Here’s my best guess at how much attenuation I need
when tuning to 2.4 GHz:

## Rx

• signal enters through HMC174MS8 T/R switch – negligible effect
• then MGA 82563 LNA – apx. 12.5 dB gain @ 2.4 GHz
• then AD8347-MIX – max input of -20 dB

Therefore, max. allowable input power @ 2.4 GHz is -20 - 12.5 = -32.5 dB
(0.56 mW)

## Tx

• signal leaves AD834X-MIX (I assumed X = 8) – max SSB output power of
-30 dB at 2.4 GHz.
• then MGA 82563 LNA – apx. 12.5 dB gain @ 2.4 GHz
• then RF3315 LNA – apx. 10 dB gain @ 2.4 GHz (spec sheet only goes up
to 2.2 GHz)
• then HMC174MS8 T/R switch --negligible effect

Therefore, max. output power @ 2.4 GHz is -30 + 12.5 + 10 = -7.5 dB (178
mW)

From these numbers I guess I need -32.5 + 7.5 = 25 dB of attenuation.
Are these number correct? I am not exactly sure if I’m using “SSB
output power” correctly.

Thanks,

• Lee

Lee P. wrote:

This one’s most likely for Matt:

I would like to connect the RFX-2400 Tx/Rx and Rx ports via coax and
some attenuators. Here’s my best guess at how much attenuation I need
when tuning to 2.4 GHz:

The RFX2400 max power is more than +13dBm.

There is enough leakage through the switches that there is no need to
connect the 2 ports at all. Just put terminations on both.

Matt