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Products => Test Equipment => Topic started by: bsodmike on August 23, 2021, 10:09:20 am

Title: Advice please for choosing a Spectrum analyser
Post by: bsodmike on August 23, 2021, 10:09:20 am
Hi all,

I'm exploring the options for a Spectrum analyser to add to my bench that currently has mainly Keysight and Rhode & Schwarz equipment.

My use-case to start is for general use on the bench, and progress onto more advance cases as I start to tweak and configure antenna designs on PCB, all under the 3GHz spectrum. VNA/Smith chart analysis would be helpful in that regard.
Other applications would be working with amplifier circuits, THD measurements etc.

Options:

One that peaked my interest is this FPC1500 model from R&S at Farnell:

- FPC-COM2 is a bundle of FPC1500 spectrum analyser with other options (Tracking generator, VNA, signal generator, preamplifier, modulation analysis, receiver mode, advanced measurements).
- Feature set: FPC1500 spectrum analyzer, Tracking generator, VNA, Signal generator, preamplifier, Modulation analysis, Receiver mode, Advanced measurements, Power cable, USB cable for connection to PC
https://export.farnell.com/rohde-schwarz/fpc-com2/spectrum-analyzer-5khz-to-3ghz/dp/3052020?st=rhode%20&%20schwarz%20spectrum%20analyser (https://export.farnell.com/rohde-schwarz/fpc-com2/spectrum-analyzer-5khz-to-3ghz/dp/3052020?st=rhode%20&%20schwarz%20spectrum%20analyser)

It has most, if not all, the extra features and a max 3Ghz freq. range.  This may be limiting to some, but this does keep the price down.

Alternatively, here's a handheld R&S unit sold on eBay:
https://www.ebay.co.uk/itm/324716919054 (https://www.ebay.co.uk/itm/324716919054)

Should I go for a new unit or consider the used unit?

Thanks, M.
Title: Re: Advice please for choosing a Spectrum analyser
Post by: nctnico on August 23, 2021, 03:14:30 pm
Why aren't you considering the Nano VNA V2 which covers your required frequency range?
Title: Re: Advice please for choosing a Spectrum analyser
Post by: David Hess on August 23, 2021, 06:53:04 pm
Why aren't you considering the Nano VNA V2 which covers your required frequency range?

VNAs are intended to operate coherently with a signal source, which considerably relaxes their performance requirements.  They make horrible spectrum analyzers.

https://youtu.be/xMQZTy3iV9o
Title: Re: Advice please for choosing a Spectrum analyser
Post by: nctnico on August 23, 2021, 07:55:00 pm
Why aren't you considering the Nano VNA V2 which covers your required frequency range?

VNAs are intended to operate coherently with a signal source, which considerably relaxes their performance requirements.  They make horrible spectrum analyzers.

Well, the OP states antenna tweaking. For that purpose a VNA is the right tool and the thread title might be wrong.
Title: Re: Advice please for choosing a Spectrum analyser
Post by: jjoonathan on August 23, 2021, 08:01:56 pm
A fast SA+TG beast a slow VNA for antenna tuning. Of course, a fast VNA is better still, but that begs the question: is the NanoVNA fast, or is it fast per dollar?
Title: Re: Advice please for choosing a Spectrum analyser
Post by: ogden on August 23, 2021, 08:30:31 pm
Twin listing of same FSH3 has more photos, one showing 1-port device, yet listing claims K2 option. I would be very careful here. https://www.ebay.com/itm/324716919054 (https://www.ebay.com/itm/324716919054)
Title: Re: Advice please for choosing a Spectrum analyser
Post by: bsodmike on August 24, 2021, 03:10:28 am
Hi Nico - Yes, sorry I did mention antenna tweaking but I don’t only want the VNA function alone. I would like to also have the features of a Spectrum analyzer as well. Think of having the VNA as an added feature.

Ogden: thanks for the heads up!!
Title: Re: Advice please for choosing a Spectrum analyser
Post by: tautech on August 24, 2021, 03:24:47 am
Does brand loyalty have you overlook SVA1032X ?
Title: Re: Advice please for choosing a Spectrum analyser
Post by: bdunham7 on August 24, 2021, 04:18:05 am
Why aren't you considering the Nano VNA V2 which covers your required frequency range?

VNAs are intended to operate coherently with a signal source, which considerably relaxes their performance requirements.  They make horrible spectrum analyzers.

https://youtu.be/xMQZTy3iV9o

"I can't predict when it is going to act correctly and when it's not going to act correctly"

Best quote I've seen in a while and one everyone should remember when evaluating test equipment!

The NanoVNA does some things pretty well, but SA isn't one of them.  Probably worth having though even if you have other tools because you can take it places and it goes into nooks and crannies--which allows you to use very short leads.
Title: Re: Advice please for choosing a Spectrum analyser
Post by: bdunham7 on August 24, 2021, 04:25:18 am
Does brand loyalty have you overlook SVA1032X ?

I'm just curious--can you comment on the comparative option packages?  Hackability aside, it looks like R&S actually might offer a lower price for equivalent performance, if they are equivalent.  That would be interesting.
Title: Re: Advice please for choosing a Spectrum analyser
Post by: bsodmike on August 24, 2021, 05:42:20 am
Well, I have an official local distributor and they can import Keysight / R&S as agents to Farnell UK. This means they will also honour the usual 3-year warranty on most R&S equipment.  Downside is they charge a ~25% profit margin.
Title: Re: Advice please for choosing a Spectrum analyser
Post by: ogden on August 24, 2021, 05:31:25 pm
it looks like R&S actually might offer a lower price for equivalent performance

Far from that. Grab your calculator and see:

Siglent SVA1032X 3.2GHz with VNA option enabled: € 3,533.11

R&S® FPC1500 1GHz SA: € 2,891.70
+ R&S® FPC-K42 Vector Network Analysis : € 892.50
+ R&S® FPC-B2 Upgrade 1 GHz>2 GHz : € 999.60
+ R&S® FPC-B3 Upgrade 2 GHz>3 GHz : € 999.60
Title: Re: Advice please for choosing a Spectrum analyser
Post by: bdunham7 on August 24, 2021, 06:45:01 pm
Far from that. Grab your calculator and see:

Look at the OP's link--R&S/Farnell are offering a deal of sorts:

"FPC-COM2 is a bundle of FPC1500 Spectrum Analyser,, 5kHz to 3GHz, Extra Software Options (Tracking generator, VNA, signal generator, preamplifier, modulation analysis, receiver mode, advanced measurements). "

£3,841.00
Title: Re: Advice please for choosing a Spectrum analyser
Post by: David Hess on August 24, 2021, 08:38:10 pm
A Nano VNA V2 is so cheap in comparison that it may be worth getting one just to see if it will be sufficient for your application.

They do make combination VNA and spectrum analyzers like the R&S VNL and ZNL series if you really need both but they cost even more.
Title: Re: Advice please for choosing a Spectrum analyser
Post by: tv84 on August 24, 2021, 10:26:07 pm
A Siglent SSA3021X Plus can be bought with 1.750€ (VAT included) and converted to a full optioned SVA1032X.

There is plenty of information on this forum about this conversion.
Title: Re: Advice please for choosing a Spectrum analyser
Post by: bsodmike on August 25, 2021, 02:45:23 pm
Seems this deal is only on till end of the month.  I saw the promotion here:
https://www.batronix.com/shop/spectrum-analyzer/Rohde-Schwarz-FPC-COM2.html (https://www.batronix.com/shop/spectrum-analyzer/Rohde-Schwarz-FPC-COM2.html)

Quote
R&S Full Package FPC1500
Full Package FPC1500 incl. FPC-B2 bandwidth Upgrade, FPC-B3 banwidth Upgrade, FPC-B22 preamplifier, FPC-K7 modulation analysis, FPC-K42 vector network analysis, FPC-K43 receiver mode and FPC-K55 advanced measurement.
(Valid until August 31, 2021)
Title: Re: Advice please for choosing a Spectrum analyser
Post by: MagicSmokeGuy on September 11, 2021, 07:35:36 am
One feature of the R&S unit over the Siglent is that it has a built in signal generator which is very useful.  As far as I am aware, the TG on the Siglent cannot be run standalone and also has a poorer performance with regards to signal purity etc.