shopping for a spectrum analyzer - Page 1
Forum section: electronics / testgear

author: worsthorse
author_rank: Super Contributor
timestamp: April 14, 2017, 03:42:57 am
content: I am shopping for an entry level spectrum analyzer with a tracking generator. I spend most of my time below 50MHz working with amateur radio gear. I have been looking at used Instek GSP-810s. At 400 bucks or so, especially compared to the SDR-based homebrew unit I am using now, they seem like a pretty good deal. I've looked at old used gear too but, honestly, I don't know enough about the high end stuff to know a good deal from bad and I certainly don't have the expertise (yet) to repair such stuff.I've noticed though that there are very few reviews of the entry SAs in general and the 810 in particular. Anyone have one? Use one? Have an opinion? Is it just silly to think I can get a decent SA for under a thousand bucks? two thousand? Is there some used HP, etc SA I really should consider instead, as painful as it will be for my wallet?Thanks in advance! - b

author: tautech
author_rank: Super Contributor
timestamp: April 14, 2017, 03:54:48 am
content: These are pretty well thought of on the forum.https://www.eevblog.com/forum/testgear/siglent-ssa3000x-spectrum-analyzers/https://www.eevblog.com/forum/testgear/hack-of-sigllent-spectrum-analyzer-ssa3021x/https://www.eevblog.com/forum/blog/eevblog-892-siglent-ssa3021x-spectrum-analyser-teardown/

author: nctnico
author_rank: Super Contributor
timestamp: April 14, 2017, 09:01:38 am
content: There are lots of SAs from Advantest on Ebay and good deals can be had on compact units like the R3131 / R3131A. However many don't have a tracking generator and I think the reason is that a tracking generator isn't really usefull. For example: If you measure an antenna or filter you'll also want phase information so you can see what you need to modify in your circuit. For that you'll need a vector network analyser. A vector network analyser can be used as an LCR meter and a spectrum analyser as well so it is also a multi function instrument.

author: biot
author_rank: Regular Contributor
timestamp: April 14, 2017, 12:25:40 pm
content: Quote from: tautech on April 14, 2017, 03:54:48 amIt is considered proper in conversations like this that you disclose the fact that you are a Siglent dealer. By not doing this, and instead shamelessly astroturfing your brand, you will achieve rather the opposite effect from what you intended.

author: srce
author_rank: Regular Contributor
timestamp: April 14, 2017, 12:56:50 pm
content: Quote from: biot on April 14, 2017, 12:25:40 pmIt does say that in his signature - the line of text below what you quoted.

author: worsthorse
author_rank: Super Contributor
timestamp: April 14, 2017, 01:23:48 pm
content: spent the morning looking at the 810 specs. now i know that won't work. also found a thread on used equipment which is, unfortunately, 25 pages long. looks like the HP 8591 is a contender in the old category, and the siglent/rigol gear in the new. it also looks like i am not going to get away with spending less than $1300 - $1800, which may put it out of range.i am going to dig through that 25 page thread some more. any guidance on the old gear is appreciated. there seems to be plenty to read on the siglent/rigol gear. thx.

author: videobruce
author_rank: Frequent Contributor
timestamp: April 14, 2017, 01:52:13 pm
content: Attached are two spreadsheets on some current lower cost SA's with added details/comments from my experience with them. These are either current or fairly recently discontinued.No 'boat anchors'.Updated & revised lists; added new Instek models!

author: nctnico
author_rank: Super Contributor
timestamp: April 14, 2017, 06:57:41 pm
content: Sigh... more test equipment dealers chiming in and parading their stuff without even considering the OP's question.@wch: I don't think the GSP-810 is a good buy at around $400. I'd spend a bit more and get a used digital spectrum analyser. With some research and patience good deals can be found on Ebay.

author: kgharibyan
author_rank: Newbie
timestamp: April 14, 2017, 07:48:20 pm
content: May be this one ?http://www.deepace.net/shop/kc901s/Sent from my iPhone using Tapatalk

author: bozidarms
author_rank: Regular Contributor
timestamp: April 15, 2017, 07:27:44 am
content: By far, Siglent's SSA3000X are the best choice!

author: videobruce
author_rank: Frequent Contributor
timestamp: April 15, 2017, 12:58:49 pm
content: Quote from: Flinstone on April 14, 2017, 06:31:45 pmInteresting, but R&S isn't a huge name in the states and their UI is (or has been) unconventional which I noted in my comparison charts. This has been reflected elsewhere by others.Quote from: kgharibyan on April 14, 2017, 07:48:20 pmNever heard of them and there isn't a US distributor.

author: rstofer
author_rank: Super Contributor
timestamp: April 15, 2017, 02:29:34 pm
content: The 500 MHz Rigol DS705 is just under $700. It doesn't have the noise specs of the Siglent SSA3000 or even the better Rigols but maybe it will do the job. Or not...https://www.rigolna.com/products/spectrum-analyzers/I would rather have a new device with a warranty. Buying used test equipment seems risky even though it has worked out well for me.But my signal generator, DSO and power supply were bought new. I have a used scope and a couple of used bench DMMs and they all work fine.

author: videobruce
author_rank: Frequent Contributor
timestamp: April 15, 2017, 03:43:25 pm
content: I updated those lists I posted.

author: james_s
author_rank: Super Contributor
timestamp: April 15, 2017, 03:59:53 pm
content: I only buy used test gear, it may be a bit of a gamble but I've saved vast sums of money and ended up with much better gear that I could have afforded buying new. I can't actually think of a single instance where I got screwed and the item turned out to be junk. I often buy known defective equipment and more often than not the problem turns out to be simpler than expected. It saves enough that I could afford to be burned now and then.

author: hendorog
author_rank: Super Contributor
timestamp: April 15, 2017, 08:01:28 pm
content: Quote from: kgharibyan on April 14, 2017, 07:48:20 pmHave seen those products advertised for quite a while. The newer KC901V model has some improvements which improve accuracy apparently. Would be interesting to see it tested."The KC901V is a RF multi-instrument integrating VNA, spectrum analyzer, field strength meter, and a low-frequency signal generator. It can do complete signal port vector measurement and 2-ports simple vector network analyzing."There are also the SignalHound products, Spectrum and Track gen bundle for $1472.https://signalhound.com/products/4-4-ghz-scalar-network-analyzer/

author: G0HZU
author_rank: Super Contributor
timestamp: April 15, 2017, 10:31:05 pm
content: Quote from: james_s on April 15, 2017, 03:59:53 pmSame for me. I try and be patient and pick up used bargains either ex rental or from ebay or from the skip/dumpster at work. The most I've spent on a spectrum analyser is £1000 about 6 years ago for an ex rental HP8566B 22GHz analyser. At the time this was a huge bargain not to be missed. But before that the most expensive was my old Advantest TR4172 at £400. Most recent is an old Tektronix RSA3408A RTSA rescued from a trip to the skip at work. It's a bit of a dog when used as a conventional spectrum analyser but is very powerful as an RTSA. It's horrible to use but it was free

author: joeqsmith
author_rank: Super Contributor
timestamp: April 16, 2017, 03:29:07 am
content: Quote from: wch on April 14, 2017, 03:42:57 amWhat is it that you need to do that the one you have doesn't support?

author: videobruce
author_rank: Frequent Contributor
timestamp: April 17, 2017, 12:13:33 pm
content: QuoteIn that price range, you might as well get the Siglent.One dedicated device, not two that are severely limited in what they can do. Actually, don't you need a Laptop to tie the two pieces together??Doing more 'new model' research, I stumbled across two new models from Instek which are basically variations in the existing 9300, one apparently marketed to the Siglent/Rigol crowd.This two spreadsheets 12 posts back now reflect the addition.

author: G0HZU
author_rank: Super Contributor
timestamp: April 17, 2017, 12:51:59 pm
content: QuoteThe Signalhound SA44 can act as an SDR and display a ham band and demodulate typical ham signals on the HF bands. I don't think the Siglent can do this. Also the phase noise of the Signalhound is pretty decent on the HF bands.By comparison the Siglent's phase noise is going to be awful, really awful for serious monitoring of the HF bands. Maybe not PLay Doh noise performance but pretty grim unless you just want to look for medium to big signals rather than little signals next to big signals.

author: videobruce
author_rank: Frequent Contributor
timestamp: April 17, 2017, 01:16:26 pm
content: Anyone else on those observations? (HF phase noise)

author: G0HZU
author_rank: Super Contributor
timestamp: April 17, 2017, 01:53:55 pm
content: For an extreme example I can show the noise performance of my dumpster RSA3408A on 14MHz. This analyser has very low phase noise on the HF bands because it feeds direct to the 14bit ADC for all frequencies up to about 40MHz and can easily detect a signal 100kHz away that is -80dBc on the 14MHz (20m) ham band. It could easily manage -90dBc with the analyser set to a typical comms bandwidth of 3kHz on the HF bands.But I've drawn in red what I think the Siglent analyser noise will look like. It will totally mask the smaller signal. I'd expect the signalhound to be better than the Siglent here but obviously it won't match the old Tek analyser. All of my old school spectrum analysers can detect the -80dBc signal with a RBW of 3kHz but the HP8566B and the HP8568B struggle here a bit. My old Advantest analyser does well here as it has -128dBc/Hz phase noise at 100kHz offset. I think the Siglent manages about -98dBc/Hz here. I'm going to guess that the Signalhound will manage -120dBc/Hz here although I've not used one.

author: hendorog
author_rank: Super Contributor
timestamp: April 17, 2017, 08:51:48 pm
content: Quote from: videobruce on April 17, 2017, 12:13:33 pmYes you need a laptop/PC. That and the lack of knobs does affect its convenience on the bench, but the trade-off is portability and 'natural' PC access to device for e.g. data and screenshots. It's a great device for the inquisitive as you can pick it up and use it anywhere and power it from a laptop.There are limitations but hardly 'severely limited'. Certainly worth considering in competition with the other products you have included in your SS.The main limitation is the switching IF method used to remove images. This is a pain when looking at signals which hop around but not an issue for normal ham stuff.For such signals you need to switch it off and deal with any images or use max hold.There are some advantages which I think are unique in the price range:* Very portable* Modular* Higher frequency by quite a margin than anything in the price range* Lowest cost* PC integration (Labview available, HDSR available, GNURadio not yet)

author: james_s
author_rank: Super Contributor
timestamp: April 17, 2017, 08:56:57 pm
content: I've had a PC based Bitscope for years and have never found it to be particularly convenient as a scope. Sure it's nice to be able to capture and save easily on the PC but using a mouse or touchpad is not nearly as convenient as buttons and knobs on a standalone device. Also I've had issues with the USB port locking up unless an isolator is used, and driver issues, I never was able to get it to work properly on my current Win7 laptop, neither does my USB to DMX interface, they work fine on the old XP laptop though.

author: G0HZU
author_rank: Super Contributor
timestamp: April 17, 2017, 09:03:57 pm
content: QuoteI've often wondered how well this works in practice with the SA44B. How does it deal with wideband signals that look like noise or wideband pulsed signals? For ham use and the odd bit of EMC sniffing I suspect that the Signalhound would be quite a powerful tool.I wouldn't want to buy one but I'd be interested to see how the unconventional image rejection system performs.

author: hendorog
author_rank: Super Contributor
timestamp: April 17, 2017, 09:32:51 pm
content: Quote from: G0HZU on April 17, 2017, 09:03:57 pmThose types of signals would be kicked out by the image rejection, and it would need to be turned off to see them reliably.There is however a narrowband (<250kHz) 'real-time' mode which will capture fast modulating signals, and the API could presumably be used to assemble many of these to view a wider bandwidth.

author: videobruce
author_rank: Frequent Contributor
timestamp: April 18, 2017, 12:53:59 am
content: I know with the Tek SA that requires a laptop, the ability to get the full benefit out of their SA you need a high end (expensive) Wintel processor that can handle the high level processing needed.

author: hendorog
author_rank: Super Contributor
timestamp: April 18, 2017, 01:06:08 am
content: Quote from: videobruce on April 18, 2017, 12:53:59 amThe Tek RSA306 (and the SH BB60C) are wide bandwidth realtime SA's and not comparable to the narrowband SA44B or SA124B.The two realtime boxes are USB 3.0, while the SA products are USB 2.0. Max realtime bandwidth of the SA products is just 250kHz whereas the Tek and BB60 are 40MHz and 27Mhz respectively IIRC. All of that data needs to be streamed to the PC for processing which is why you need a decent machine for the wide bandwidth products.

author: videobruce
author_rank: Frequent Contributor
timestamp: April 18, 2017, 01:10:26 am
content: QuoteWhich was my point. You need a high end machine.

author: hendorog
author_rank: Super Contributor
timestamp: April 18, 2017, 01:23:13 am
content: Quote from: videobruce on April 18, 2017, 01:10:26 amYes of course you are correct.Since we were talking about the SA44B previously I thought it was worth clarifying that they don't need a high spec machine.

author: bozidarms
author_rank: Regular Contributor
timestamp: April 18, 2017, 12:51:46 pm
content: QuoteI can hardly understand what is a purpose of comparing a "dumpster" RSA3408A with Siglent SSA3000.This "dumpster" RSA3408A have used, "dumpster" price almost 15x more than a new Siglent SSA3000 analyzer!And, when a phase noise of interest is, then a Perseus SDR is unbeatable - over147dBc/Hz just 10 kHz away,much, much better than any Signalhound analyzer (and also a resolution in mHz, if is it needed)!Regards

author: nctnico
author_rank: Super Contributor
timestamp: April 18, 2017, 01:10:24 pm
content: Quote from: hendorog on April 18, 2017, 01:23:13 amFrom what I've read the Signal Hound software also likes a PC with a hefty CPU to work conveniently.

author: G0HZU
author_rank: Super Contributor
timestamp: April 18, 2017, 03:45:33 pm
content: QuoteThe Tek plot was intended as an ideal reference to demonstrate the two test tones as cleanly as possible and show how significant an analyser with high phase noise can be. This test required an analyser with very low phase noise and also a decent sig gen with lower phase noise than the Tek analyser. Think of the Tek plot as an ideal view of the spectrum rather than a performance comparison. Nowhere did I suggest that the RSA3408A was a realistic/alternative purchase option. In the text of my post I indicated that the Signalhound would probably be 20dB better than the Siglent at 100kHz offset. That was what kicked this off. Signalhound phase noise vs Siglent on the HF bands.

author: bozidarms
author_rank: Regular Contributor
timestamp: April 18, 2017, 04:03:34 pm
content: Tnx for explanation - my comment was not intended to be crude.Anyway, the whole story with dumpster gear is quite amusing.It seems that you (like Dave) have access to very interesting "dumpsters"?

author: worsthorse
author_rank: Super Contributor
timestamp: April 18, 2017, 08:55:36 pm
content: Quote from: joeqsmith on April 16, 2017, 03:29:07 amThat's a reasonable question. Fundamentally? Predictability and ease of use. I find the PC-based solutions for test gear hard to set up, hard to use, and the results hard to replicate from setup to setup. I can make it work but for the amount of time I spend using it, the getting-it-working time is expensive; a box SA will suit me better.On new versus used... Other than my Rigol oscope and a no name DVM, all of my radio gear and test equipment is used or homebuilt, so I am comfortable buying used gear even if I am not qualified to fix it if it fizzles on me. So far, I've been lucky, I guess, in my purchases.I got interested in the GSP-810 because the $400 price seems to buy a lot. On the other hand, I am a little suspicious of relatively recent vintage $3500 equipment selling for $400 used. That often means it was way more expensive than it should have been from go.But I want the best of all worlds... I want an SA with a TG and I don't want to spend $1500 to $2000 for it. I mean, my most expensive radio cost less than that. That might just be impossible. 73 de bill

author: hendorog
author_rank: Super Contributor
timestamp: April 18, 2017, 09:57:24 pm
content: Quote from: nctnico on April 18, 2017, 01:10:24 pmI've been using it on a Thinkpad T420s (circa 2011 i5 I think) and also on a T460s (i7) and I don't recall noticing any difference. This is with an SA124B, so USB2 and not wide bandwidth.So I think anything that is reasonably modern should be fine for the SA products.I have had problems with disconnections when using it via Parallels on a 2012 era Macbook Pro, which I think was caused by latency due to the VM. There was a patch a while back which improved that somewhat IIRC.

author: G0HZU
author_rank: Super Contributor
timestamp: April 19, 2017, 12:55:12 am
content: QuoteCompared to the 810 the HP 8591 is a massive improvement, worlds apart, but this is more an indication of how limited the 810 is rather than how good the HP8591 is. The HP8591 is going to be fine for a lot of ham stuff and it's a very popular analyser but in the professional world the HP8591 was never a great analyser. It looks nice and even looks similar to other HP analysers that are much better than the HP8591.It's mainly meant to be used as a low to medium spec portable analyser for use in the field. Maybe something a tech would use to gather data on a field trial, then log/store the results to a memory card and process the results back at the lab. It only has an 80dB display of which 70dB are spec'd as logarithmic and the display quality is poor and cramped. Some models only have a minimum RBW of 1kHz. Prices vary a lot but I would never pay £1000 for one of these old analysers. If you can get one cheaply then go for it but it is always going to be a dog in performance terms and display quality when compared to the other used alternatives.I think that most (fairly serious) ham/hobby users would be much better off (and much happier) with the Siglent analyser even though it costs probably double the price of a used HP8591. However, if you just want to tinker and make very casual measurements and you can live with the display and 70dB log range and limited RBW performance then maybe consider the HP8591. But just don't sit it alongside the Sigent and compare the features, the display or the log range or the tight RBW filters the digital IF in the Siglent offers plus all the modern connectivity the Siglent offers.Don't be seduced by the looks and the HP name/reputation behind the HP8591. This was very much a low performance analyser even when it was new 30 odd years ago.

author: usagi
author_rank: Frequent Contributor
timestamp: April 20, 2017, 09:39:39 am
content: Quote from: wch on April 14, 2017, 03:42:57 ami would not recommend a GSP-810, the limited RBW will be pretty useless for ham HF use.a used R&S CMU200 can be had for under $1k. it will get you down to 10mhz. it doesnt have a true TG, but it has TG functionality.if you're not hung up on a TG requirement, there are a lot of other options available. see my sig.

author: worsthorse
author_rank: Super Contributor
timestamp: April 23, 2017, 03:42:23 am
content: That post is terrific. Thanks for doing the work. I need to spend some time looking at the field now...

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 26, 2017, 03:47:09 am
content: Quote from: kgharibyan on April 14, 2017, 07:48:20 pmjust want to make precaution for future buyers/readers... if the main intention is "spectrum analyzer", deepace network analyzer series (KC901V that i recently owned, and i suspect similar to KC901S) is not really recommended unless you have full control of the DUT's freq output. KC901x series only work well as spectrum analyzer if the DUT frequency lies exactly (or very close to) on the step frequency of the SA sweep, or some work around is tolerable, otherwise the spectrum display will come and go, a very trap for young padawan. i think i'm going to make a small review about this matter sometime.