Slighty faulty HP141t question
 

hello...

my old but trusty hp141t (1.2ghz) appears to have developed a fault/out of
calibration??

it all works but now there is a spurious reading (peak) about 6.5mhz down
from the fundamental peak..about 55db down..its always there when a signal
is present (but not of course when no input.)
It's defiantly the analyser as I have tried different tx sources and its
always present..
sniffing rf via bird 43 attenuator..

Any ideas??

simon g0zen

When you switch in an extra 10 db of attenuation at the input, does
the spur drop 10 db as well as the wanted signal drop 10 db?
If spur drops more then IM is being generated in the analyzer from
overload possibly.

73
Gary K4FMX


On Tue, 23 Nov 2004 12:38:05 -0000, "zindazenda"
wrote:

hello...

my old but trusty hp141t (1.2ghz) appears to have developed a fault/out of
calibration??

it all works but now there is a spurious reading (peak) about 6.5mhz down
from the fundamental peak..about 55db down..its always there when a signal
is present (but not of course when no input.)
It's defiantly the analyser as I have tried different tx sources and its
always present..
sniffing rf via bird 43 attenuator..

Any ideas??

simon g0zen

yes it seems to drop 10db as well...its possible to "remove" the spur by
switching in more attenuation, but doing this completly removes the 2nd/3rd
harmonics as well..which is after all what I am trying to look at..

oh the plug ins are 8552a and 8554b

simon
"Gary Schafer" wrote in message
...
When you switch in an extra 10 db of attenuation at the input, does
the spur drop 10 db as well as the wanted signal drop 10 db?
If spur drops more then IM is being generated in the analyzer from
overload possibly.

73
Gary K4FMX


On Tue, 23 Nov 2004 12:38:05 -0000, "zindazenda"
wrote:

hello...

my old but trusty hp141t (1.2ghz) appears to have developed a fault/out
of
calibration??

it all works but now there is a spurious reading (peak) about 6.5mhz down
from the fundamental peak..about 55db down..its always there when a
signal
is present (but not of course when no input.)
It's defiantly the analyser as I have tried different tx sources and its
always present..
sniffing rf via bird 43 attenuator..

Any ideas??

simon g0zen