[Microwave] Measurement interpretation.

[DAKA Technology Johannesburg]

Hi all,
 
    I have a question regarding what an analyser will display when a
WLAN is connected!
 
I have a WLAN card that operates in the 5.8GHz band and allegedly gives
out +20dbm (OFDM modulation) and runs at a 25MHz channel spacing.
 
I connect this to an old but calibrated, and trusty TEK 492, press the
max hold button and select peak store.
 
The display shows the expected shape of the channel occupancy but the RF
level is too low. For this board it shows a peak RF level around 20 db
less ie about 0dbm.
 
I do understand that the resolution bandwidth will effect the displayed
results (currently set to the 492's max of 1MHz) and note that the
displayed RF level is about 10db lower when going to 100KHz resolution
bandwidth.
 
My question is that for a WLAN unit that is giving out what the
manufacturers specify (say +20dbm) what should I expect to see on the
analyser. Is there a relationship between the analyser bandwidth, the
WLAN channel width or similar specifications that I can use?
 
Thanks & 73 to anyone able to help.
 
Dave ZS6BNT / G3ZGZ

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