22-06-2012, 12:10 PM
Ah yes, spectrum analyzers: wonderful things, provided that you:
(a) get one that is of a reputable make,
(b) get to understand its limitations, since they can easily give erroneous results,
and
© be very careful not to damage it!
For (a), I am thinking of HP, Tek and Anritsu; that's based on my experience.
For (b), you need to be aware that there can be combinations of input signal levels and control settings that will give misleading results.
For ©, this remark is really limited to using an analyzer with high R.F. power sources - such as transmitters: always insert an attenuator pad (typically 30 dB) between that TX and the analyzer's input, to avoid burning out the input attenuator on account of sheer overload. (Please don't ask me how I know this!
)
There are basically two distinct types of analyzer: ones with and ones without a tracking generator (T.G.). Those without are O.K. for things like EMC and field strength measurements, but if you need to look at the response of things like filters, amplifiers, etc., you do need to have a tracking generator. Early analyzers tended to have a T.G. as a separate box; modern ones have them integrated into the unit.
Probably one of the commonest S.A.s on the second-hand market these days is the HP 141T: they typically change hands in the region of £300 - £400. At the other end of the market, there are things like the Tek 494 (> £3000) and the superb Anritsu MS2687B (typically £14k - £15k). The Anritsu range with the prefix MS26xx are superb analyzers and a joy to use . . . but they don't come cheap!
Al.
(a) get one that is of a reputable make,
(b) get to understand its limitations, since they can easily give erroneous results,
and
© be very careful not to damage it!
For (a), I am thinking of HP, Tek and Anritsu; that's based on my experience.
For (b), you need to be aware that there can be combinations of input signal levels and control settings that will give misleading results.
For ©, this remark is really limited to using an analyzer with high R.F. power sources - such as transmitters: always insert an attenuator pad (typically 30 dB) between that TX and the analyzer's input, to avoid burning out the input attenuator on account of sheer overload. (Please don't ask me how I know this!
)There are basically two distinct types of analyzer: ones with and ones without a tracking generator (T.G.). Those without are O.K. for things like EMC and field strength measurements, but if you need to look at the response of things like filters, amplifiers, etc., you do need to have a tracking generator. Early analyzers tended to have a T.G. as a separate box; modern ones have them integrated into the unit.
Probably one of the commonest S.A.s on the second-hand market these days is the HP 141T: they typically change hands in the region of £300 - £400. At the other end of the market, there are things like the Tek 494 (> £3000) and the superb Anritsu MS2687B (typically £14k - £15k). The Anritsu range with the prefix MS26xx are superb analyzers and a joy to use . . . but they don't come cheap!
Al.
