Author Topic: Which spectrum analyzer  (Read 3714 times)

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Offline R_G_B_

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Which spectrum analyzer
« on: November 29, 2014, 10:25:06 am »
I am Looking for a spectrum analyzer for EMC testing up to 5.8GHz however I see these cost many thousands of pounds.

I use the analogue discovery for low frequency testing which has a spectrum analyzer function with 88dB dynamic range and is useful up to 10Mhz

one could combine this with the RF Explorer range 15Mhz to 2.7GHz
but what about the ranges 10Mhz to 15Mhz and 2.7Ghz to 5.8GHz things get messy.

If I use an oscilloscope FFT function with limited 48dB dynamic range to cover frequencies 10MHz to 15MHz and
Down convert from 5.8Ghz to 2.4Ghz. Does anyone have a better solution to this problem?

R_G_B






Basical the above seems
 
 
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Offline VK5RC

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Re: Which spectrum analyzer
« Reply #1 on: November 29, 2014, 10:34:54 am »
Unfortunately SpecAnalysers get really expensive but don't do what I did and buy a crappy USB type first, my second purchase, an old HP is worth its weight  (and that is quite a lot) in gold.
Signal Hound I have read some good reports but they are not cheap either.
As a ham I actually use a Spec Analyzer more than a scope. If you want your EMC measurements to be reliable/repeatable you also need good gear.
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Offline HighVoltage

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Re: Which spectrum analyzer
« Reply #2 on: November 29, 2014, 10:42:07 am »
I bought an older HP SP for up to 12 GHz and in addition a new Rigol DSA815TG
With both of them I cover a good range of the spectrum and saved a lot of money.
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Offline R_G_B_

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Re: Which spectrum analyzer
« Reply #3 on: November 29, 2014, 10:52:13 am »
The RF Explorer has some good functions. Even a signal generator:

 http://micro.arocholl.com/index.php?option=com_content&view=article&id=124:rf-explorer-signal-generator&catid=40:article&Itemid=64


Shame about the frequency range. If a future add on becomes available to expand the frequency range then this would be a good option as I see it there have been discussion about expanding the frequency range but nothing seems to happened regarding this.

R_G_B 
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Offline nixfu

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Re: Which spectrum analyzer
« Reply #4 on: November 29, 2014, 11:06:29 am »
RFExplorer is supposed to be expanding down to hz range for audio-through-ghz capabilities in the future, according to what they told me when I asked them. They also have a new low cost tracking generator available as well that pairs with their units.

So less than $500 or so for both a spectrum analyzer + tracking generator.  Not a bad deal. 

But as a ham, right now the fact they can't go below 15MHz is too limiting to consider their products. 

It is not useful for testing bandpass filters, or any audio, or testing most intermediate (IF) frequencies used in radio designs which are often single mhz range, etc..

For ham radio use, ideally something in the Hz to 1GHz range is what you really need.

Outside of getting a deal on a an older used HP, the Rigol 815 is probably the best band for the buck. 

As a hobbyist though $1000 is little bit much for a single piece of test gear, and I am hoping for a cheaper solution. 

The RF Explorer will be the perfect solution for my needs if they ever extend the range down.  Even with a little reduced sensitivity ranges it will work for my hobby needs.

« Last Edit: November 29, 2014, 11:15:33 am by nixfu »
 

Offline R_G_B_

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Re: Which spectrum analyzer
« Reply #5 on: November 29, 2014, 11:15:23 am »
Yes I am aware of the sub 15MHz limitations you mention.

looking at the webpage it says that there will be future expansions. The new signal generator works from 22hz to 6Ghz.
so maybe they have an expansion module in the pipe line as you have said. Also The RF explorer has an expansion port just a matter of when will they offer the upgrade.



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Offline larry42

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Re: Which spectrum analyzer
« Reply #6 on: November 29, 2014, 07:07:25 pm »
You write "EMC testing" - but what are you trying to test?

Most EMC standards are radiated emissions (30MHz  to >12GHz) and susceptability (3V/m) - this normally requires antennas (expensive ones) too.
Testing only up to 5.8GHz won't show the 2nd and 3rd harmonics, which are often problematic.

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