Spectrum Analyzer recommendation - Page 1
Forum section: electronics / general

author: bsgd
author_rank: Regular Contributor
timestamp: January 27, 2012, 02:23:32 pm
content: Hello folks,I've been wanting to get a Spectrum Analyzer for years, but I never found something 'cheap' enough that could fulfil my needs at the same time that I had the money to spend. By cheap I mean something below $1K.I mostly work with audio stuff, so I need frequencies from 10Hz to 50 or 100kHz basically. I would also like to find a lightweight device because I would need it shipped internationally since here in my country theres no way I can find such instrument.By lightweight I mean something that doesnt weight so much that simply cant be shipped anywhere.I have been looking at a HP 3580A for some time but I couldnt find any for sale. What would you guys recommend?Thanks.

author: Bored@Work
author_rank: Super Contributor
timestamp: January 27, 2012, 02:41:54 pm
content: I have seen solutions with high-end soundcards or DAQ hardware plus software for PCs. Some of the PC software was even free software.

author: ejeffrey
author_rank: Super Contributor
timestamp: January 27, 2012, 02:47:17 pm
content: For such low frequencies, have you considered a sound card based audio spectrum analyzer? It is hard to beat free. What are your requirements?

author: olsenn
author_rank: Frequent Contributor
timestamp: January 27, 2012, 04:02:25 pm
content: Or even a DSO with fft (granted it probably isn't as responsive). Personally, I am thinking of buying the new Rigol DSA815 which goes from 9KHz to 1.5GHz and is only $1500. It looks to be pretty good so far by the specs.

author: olsenn
author_rank: Frequent Contributor
timestamp: January 27, 2012, 04:03:12 pm
content: Here's the link:http://int.rigol.com/prodserv/DSA800/

author: bsgd
author_rank: Regular Contributor
timestamp: January 27, 2012, 04:28:32 pm
content: Quote from: ejeffrey on January 27, 2012, 02:47:17 pmMy requeiremets are very simple! I just need to be able to check the spectral content of audio frequencies. And peak to peak voltage is never above 20 or 30V maximum.A sound card based analyzer might be a good option. I'll have to search for options... what about USB spectrum analyzer? Does such things exists and would that be a good option?Quote from: olsenn on January 27, 2012, 04:02:25 pmI did see your thread about the Rigol 815. This is not exactly what I need now because it doesnt cover audio frequency, BUT I do intend to by an RF Spectrum Analyzer in the future and this might be an option. What about those ATTEN ones, any good??

author: bsgd
author_rank: Regular Contributor
timestamp: January 27, 2012, 05:20:36 pm
content: Maybe this could be a good option?http://www.vellemanusa.com/products/view/?country=us&lang=enu&id=522377Does anyone have one like this and uses the FFT function?

author: Jad.z
author_rank: Regular Contributor
timestamp: January 27, 2012, 06:10:48 pm
content: Hi bsgdTake a look at this one:http://www.aaronia.com/products/spectrum-analyzers/nf-5030-x-low-frequency-usb-analyzerBasically it is a 1Hz - 1MHz USB Spectrum Analyzer.A colleague of mine bought it 2 months ago. I asked him about its quality/functionality and he gave me a very positive feedback.Actually I am thinking of buying one of this once I save 790$

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 27, 2012, 06:29:11 pm
content: Quotehttp://www.signalhound.com/not sure if its a good option.

author: olsenn
author_rank: Frequent Contributor
timestamp: January 27, 2012, 07:55:24 pm
content: Anybody have any ideas for a good, cheap (<$2000 USD) bench spectrum analyzer?

author: robrenz
author_rank: Super Contributor
timestamp: January 27, 2012, 08:09:42 pm
content: This won't do your audio frequencies but it looks interesting for RFhttp://www.ti.com/tool/msp-sa430-sub1ghz

author: jimmc
author_rank: Frequent Contributor
timestamp: January 27, 2012, 08:56:34 pm
content: If you want to try a soundcard based analyser then a free program that I've recommended before is'Visual Analyser' fromhttp://www.sillanumsoft.org/prod01.htmSpectrum analyser, Oscilloscope, Signal generator, Counter and with a simple interface, RLC meter.Jim

author: ejeffrey
author_rank: Super Contributor
timestamp: January 27, 2012, 10:22:13 pm
content: It sounds like a sound card spectrum analyzer is suitable for your needs. That probably makes it the best choice, since a well written SA application will probably be better done than a cheap dedicated instrument. You will likely need/want a voltage divider probe to keep the voltages safe for your sound card. That should be quite easy to hand make. For a few $$$ you might look at an external soundcard, which will provide some protection to your computer in case you overdo things. I don't know if there are any of those that support 96/192 kS/s sampling rate.For the RF side of things, there are a few options for USB spectrum analyzers. I have the signalhound. It is cheap and it works. It is probably the cheapest way to get to > 4 GHz, and has a tracking generator available. They seem fairly honest about it -- it isn't the fanciest, highest quality, or best spectrum analyzer out there, but it does the job it is intended to. My biggest complaint is that the software is non-responsive during a sweep. It is easy to accidentally switch to a wide span / narrow RBW sweep that can take 30 seconds, and you if you update the settings it won't take effect until the long span is complete.The aaronia stuff, both their low frequency (Hz to a few MHz) and RF (1 MHz to several GHz) models look fantastic on paper. However, their website always gives me that shonky product vibe. They sell things like screening canopies to put over your bed to keep out the evil electric fields. This makes me think their primary customers are the (literal) tinfoil hat crowd. This doesn't mean their products don't work as advertised, but it means a lot of their customers wouldn't know if they didn't. I would love to buy some of their gear, but I haven't found any reliable reviews by people who appeared to know what a spectrum analyzer does. If anyone can point out some good reviews here, let me know. They also don't have any specifications on phase noise, and their standard model uses a normal crystal oscillator (not even a TCXO) as the timebase, with no port for an external timebase input. A TCXO is an option that lets you get resolution down to 200 Hz, but that is still not that great.

author: Unknown
author_rank: Unknown
timestamp: January 27, 2012, 10:35:08 pm
content: Quote from: bsgd on January 27, 2012, 05:20:36 pmWith 8 bits of vertical resolution, dynamic range is likely to be extremely limited, just like real DSOs.

author: ejeffrey
author_rank: Super Contributor
timestamp: January 27, 2012, 10:51:17 pm
content: Quote from: alm on January 27, 2012, 10:35:08 pmThat depends on the sample rate. Quantization noise is on the order of 0.5 LSB spread over the entire nyquist range. A high sampling rate can make up for lack of bits, at least up to a point. You also would need a good input amplifier to make sure you don't piss dynamic range away looking at signals on the low 6 bits of your 8 bit ADC. It is not desirable, you really want 12 to 16 bits if you can afford it, but you could make a passable FFT with a scope front end. Unfortunately every scope I have ever worked with has a piss poor FFT function. It is really only there to check a box on the spec sheet, and only useful in the simplest situations.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 28, 2012, 02:14:05 am
content: At my most recent job,we had a nice Spec An by IFR (Although I think it is sold under other names) which is the full-on deal,with Tracking Generator & all.It obviously was also quite costly,but had a few shortcomings:-(1) The only way you could export display pix was manually via a floppy drive.This was pretty silly,because it was new in 2005 or thereabouts,& had all sorts of ways you could control it from a PC,except that one weak spot.(2) As it was digital,its sample rate (or display rate?) was not fast enough to see a carrier rapidly changing in frequency--it displayed it as a number of carriers.This was not helpful,as the equipment had a fault where ,sometimes the PLL would lose lock & the carrier would rapidly slide up by 40MHz!We could see all these carriers,then the display would settle down to one carrier on the wrong frequency.The equipment was needed in service,so a cheap SA (I think the brand was something else,but it looked identical to the Atten) was bought,so that the operators could check if they were on frequency,& yell for help if not.This unit was a normal analog device,& for the first time,we saw the carrier sliding up in frequency,& realised the other carriers were imaginary.The "cheapie" couldn't compare with the IFR in other ways,but it did its job well,being switched on first thing in the morning,then run till closedown,& never missed a beat.For audio,you may be able to pick up an old HP on EBay,as most people pass them over,the popular units being HF to UHF.I have used a Tektronix 7L12 for audio,but it was far from ideal.VK6ZGO

author: vk6zgo
author_rank: Super Contributor
timestamp: January 28, 2012, 04:23:04 am
content: Of course,another thought is to forgo the SA altogether & go retrostyle--buy an old selective millivoltmeter.A few years back,they still used these devices for testing Audiometers & other hearing test equipment.SMs may be available on EBay fairly cheaply,or at Hamfests,etc,as most people don't know what they are for.A Noise & Distortion Test set would also be usable.The main problem with these devices is you can't make changes & see the results real-time like an SA,but they did the job,& did it well back in the day.VK6ZGO

author: bsgd
author_rank: Regular Contributor
timestamp: January 29, 2012, 03:37:08 pm
content: @ejeffrey,Right now Im leaning towards the signalhound unit. I prefer standalone equipment as I dont really like having so many things on my PC, as I'm usually using the PC for reading schematics . But I guess I wont find a 'cheap' satandalone SA.@vk6zgo,I had never heard of selective milivoltmeters before. I'll have to investigate this a little more...You mentioned the ATTEN line of analyzers. Do you think they are good units? I was thinking of manybe getting one for RF as they are the cheapest SA out there.Does any of you have any experience with ATTEN Spectrum Analyzers at all?Also, has any of you used the HP 3561A? Would it work for audio work? I dont quite comprehend the differences between a Spectrum Analyzer and a Dynamic Analyzer

author: kripton2035
author_rank: Super Contributor
timestamp: January 29, 2012, 05:02:54 pm
content: searching deeply into velleman web site leads me to this nice audio analyzer system ...http://www.vellemanusa.com/products/view/?id=525197and not that expensive at all...

author: bsgd
author_rank: Regular Contributor
timestamp: February 02, 2012, 10:37:58 am
content: Quote from: kripton2035 on January 29, 2012, 05:02:54 pmHi Kripton... well that does look nice, but mostly for use as a VU dispolay of some sort.For actual measurements I need something more professional...

author: kaz911
author_rank: Super Contributor
timestamp: February 02, 2012, 11:14:23 am
content: there is a quite nice SA on eBay -http://www.ebay.com/itm/Spectrum-Analyzer-BK-Precision-2650-Handheld-3-3GHz-FULLY-TESTED-TSCM-NO-RES-/260946481889?pt=BI_Analyzers&hash=item3cc19f52e1I have one of them and they are pretty okay for most things. Only SMA input! and no TG. Battery life is okay but very dependent on LCD brightness. Resolution is a bit on the bad side on the LCD - but connect it to a PC and you get about 4 times the resolution with optional software AK 2650.The have been a mega seller recently who sold a lot with the diamond antenna etc. The went for between $900 and $1400. This looks like one of those units.

author: tinhead
author_rank: Super Contributor
timestamp: February 02, 2012, 12:17:59 pm
content: Quote from: kaz911 on February 02, 2012, 11:14:23 amSoftware is actually not free (extra ~250$) which makes the total price equal to what new Rigol DSA815 will cost.Few months ago i would still buy these BKs or other used SA (maybe HP 8591E with option 130) butnow i chosed Rigol - 100Hz RBW (<5% accuracy, not 20% like HP or BK), typical -135db DANL @1GHzand TG for fw bucks makes Rigol dirt cheap (with TG still under 2k $)

author: kaz911
author_rank: Super Contributor
timestamp: February 02, 2012, 01:45:01 pm
content: Quote from: tinhead on February 02, 2012, 12:17:59 pmi DID write OPTIONAL :-) software.But the BK SA is fine up to 3 GHz - so for the price I still think it is a good deal. Rigol for 3GHz SA you still have to find the big wallet. And since I do a fair bit of wireless stuff - having up to 3GHz in a portable package is great - I do wish for a 6Ghz so I can squeeze the 5.8Ghz in as well. But maybe next year.The BK2650 is actually made by Micronix in Japan - and only a BK badged product.But then again - the SA selection is quite dependent on what you are going to use it for. :-)My short-list contained the BK265x, Agilent Fieldfox or Anritsu sitemaster. For bench usage I looked at HP/Agilent E856xE or E856xEC. But they are so d... expensive even 2nd or 6th hand :-)But we look forward to a Rigol SA review and tear-down then. :-)