EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Dan Moos on August 20, 2020, 11:57:08 pm
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I have a HP 8590d spectrum analyzer on the way. I notice in photos of both the specific one I bought, and other similar ones, the input doesn't appear to be BNC. The manual says that when new, it would have shipped with a male type N to female BNC.
Basically, my question is, without the adapter, does the thing have the same BBC input as my scopes, and if not, what should I get for proper basic probing? I do have BNC to SMA adapters in virtually every gender combination on the way, and an SMA to alligator clip lead coming too.
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Hi,
Spectrum analyzers typically have 50 \$\Omega\$ inputs. There are some spectrum analyzers that are 75 \$\Omega\$ input these were used mainly for cable TV, CATV.
I think option 001 is the 75 \$\Omega\$ option for the 8590D. Normally you don't want option 001.
Your oscilloscope will normally have 1M \$\Omega\$ inputs.
You cannot use normal oscilloscope probes on a 50 \$\Omega\$ SA.
You should get, (at least), a 10dB attenuator and a dc block. Most spectrum analyzers can be damaged by very low dc voltages.
Regards,
Jay_Diddy_B
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It's the physical jack I'm asking about. I have a dc block, and know about need for attenuation. I'm aware it it's 50 ohm.
What kind of physical jack do these things have?
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Ok, here's my current inventory. (Most of this is still in the mail.)
1 HP 8590D analyzer.
1 sma dc block
Collection of sma to bnc adapters, all gender combos.
2 male type N to female bnc adapters
Collection of sma inline attenuators, enough to get up to 52 db atennuation.
Sma to alligator clip lead.
Many oscilloscope probes.
Sma cables
Bnc cables
With this assortment, should I be in good shape for typical hobbyist needs?
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Hi,
The spectrum analyzer will have either a BNC or an N connector for the input.
You have Male N to BNC female on your list, so you are covered.
You may want to have a Male N to SMA female adapter on the list.
You may want some SMA pigtails with RG316 or RG174 50 \$\Omega\$ coax.
All this stuff comes in various grades
Junk -> good quality -> Metrology grade
I have had good luck with second hand good quality mainly acquired at ham radio flea markets.
Junk can be useful if you finding yourself having to cut a cable.
You may want some T pieces, although these aren't as useful as you would think in RF.
Regards,
Jay_Diddy_B
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I am pretty sure that the HP specan has a N type connector. There are adapters from N to any type BNC, SMA etc.
Something like this, https://www.ebay.com/itm/N-Male-to-BNC-Female-Coax-RF-Adapters-Connectors/312664363859 (https://www.ebay.com/itm/N-Male-to-BNC-Female-Coax-RF-Adapters-Connectors/312664363859) (quick fleabay search)
Also a DC block is recommended - protects your input from the user :) (non careful user)
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Concerning DC blocks (I did get one btw).
I presume they are basically just a high quality coupling capacitor, right? My question is, does this imply that the analyzer input is DC coupled? If so, why it be? If DC is harmful, why would they DC couple the input? I actually had assumed that the 9k lower freq. limit was because of a.c. coupling.