In article , says...
Rigth, so if in doing the measurement of frecuency at 300 Mhz with a span of
500Khz I get say 299.870 my unit is OK, rigth ?

Sure.

I don't see those big errors of 5 Mhz.

If the analyzer doesn't have a stabilization feature, and its frequency
accuracy is that good, it is pure luck. Don't count on it being that
close at any other frequency, or remaining that close at 300 MHz for
very long.

Any pointers to the user manualfor that unit ?

Try www.manualsplus.com for a hardcopy, or if a search at agilent.com
doesn't turn anything up, ftp://ftp.agilent.com/pub/manuals/ .

-- john, EK5FX