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Using ProbeSet without UBBV Preamp with NF5030  

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Moderator
(@moderator)
Member Admin
Joined: 11 years ago
Posts: 1048
06/01/2011 12:53 pm  

Now I would like to draw your attention to a funny thing that I see.
I tune the NF-5030 SPECTRAN to 20.00KHz center, 0.500KHz span, and measure with the PBS1-H2 probe a field, at 20Khz.
The default attenuator is Auto.
The peak value is 124uV.
In the next step I changed the attenuator to 0db.
Later on I change the attenuator back to Auto, but the result is not the same as before.
I have the same problem if i connect/disconnect the probe.
The only way to get the original result is to switch off the spectran, and to turn it on again.
This is really funny. I think that there is some kind of a bug here.
Can you help me out with this ?

The Probes have a 50 Ohm input, but the NF-5030 offers a high impedance input with about 1MOhm.
If you connect the probes without our external preamplifier UBBV2 directly to the NF-5030 input, the impedance match is "wrong". This results in some slight measurement changes after every connect/disconnect of the probes or if you change the attenuator.
If you use our preamplifier (which we highly recommend if you use the probe set with the NF unit) there is no match problem and the results will stay stable even after changing the attenuator or after changing the probes.

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Jakobster
(@jakobster)
Active Member
Joined: 9 years ago
Posts: 9
10/08/2011 10:53 am  

Is the case with HF units exactly the same? If I am about to carry out a measurement using sniffer probes attached to both NF and HF units at one time, but I only have one preamplifier, is there some rationalized grounds to choose which unit it should be used with?


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Moderator
(@moderator)
Member Admin
Joined: 11 years ago
Posts: 1048
10/08/2011 3:17 pm  

You should allways use the UBBV preamp to compensate match problems and to get the best gain.

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