Quote:
Originally Posted by G0HZU_JMR
Make sure to be careful if you use it with your Rigol spectrum analyzer. I wouldn't advise using it as a coupler to sniff at a (say) 4W radio because the power coupled into the analyzer would be 36dBm - 15dB = +21dBm for a 6:1 coupler. 21dBm could be enough to damage your analyzer. If the coupler develops an isolation fault then it could be even worse than this.
For coupling transmitters into an analyzer, I'd advise putting another large attenuator after the coupled port.
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That is
very sound advice. Several years ago when my employment was as a Test Engineer in the manufacturing industry of VHF broadcast transmission equipment, every engineer had a spectrum analyzer on his / her bench (Anritsu were the most common). We were rigourously instructed to
always use a 20 dB attenuator on the analyzer's input port. The Test Dep't. also had access to a full-featured HP VNA: a superb item for aligning multi-pole LPFs. One day, it was discovered that someone had (presumably) decided to use it as a spectrum analyzer and had probably poked several tens of VHF watts into its input port.
The repair bill was horrendous: management were furious, not unexpectedly!
That 'incident' aside, they were halcyon days. The work was absorbing, challenging . . . and reasonably well-paid. Unfortunately, the firm crashed during the 2006/7 recession. Early retirement inevitably followed.
Al.