We present the results of 5 Beppo SAX AO1 Core Program observations of 3C 273 performed in Jan. 1997 and compare them in detail with data obtained during the satellite Science Verification Phase ( SVP ) , in Jul .
1996 ( Grandi et al .
1997 ) .

3C 273 was about 15 % brighter in the first 1997 observation than in the last one , and , on average , a factor 2 brighter than the SVP observation .
A count rate variation in the 2–10 keV band of \simeq 12 % in \sim 0.5 day was clearly detected during the last of the four pointings .

Power–law fits with Galactic absorption to all observations yield spectral indices in the range \Gamma = 1.53 - 1.6 .
Though a power law is an acceptable representation of the data in the whole 0.1–200 keV range , there is indication of a steepening of the spectrum as the energy increases .
Residuals with respect to a single power law suggest the presence of a weak fluorescence iron line in the MECS data .
No other features are detectable .
Our data therefore mark a difference with respect to the SVP data , where a steeper power law below 0.5 keV , an absorption feature at \sim 0.6 keV , and a more prominent fluorescence iron line have been found .

The weakening of cold/warm matter signatures in our data with respect to the SVP ones may indicate that , at higher luminosities , the featureless continuum produced in a relativistic jet overwhelms any thermal and/or reprocessed radiation , while the two components were almost comparable during the lower state of Jul .
1996 .

We quantitatively test this scenario , by considering an emission model which comprises the contribution from a thermal Seyfert–like nucleus and a non–thermal power–law component , and find that indeed the observed features in both the AO1 and SVP data are consistently reproduced by varying only the intensity of the non–thermal emission .
Within this scenario , this radio–loud source shows evidence not only for thermal disk–like emission , but also substantial reprocessing of X–rays onto cold matter .
There is no evidence of a direct correlation between the two components .