shopping for a spectrum analyzer

[videobruce]

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.

[hendorog]

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.

The 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.

[videobruce]

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.

Which was my point. You need a high end machine. 

[hendorog]

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.

Which was my point. You need a high end machine. 

Yes 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.

[bozidarms]

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 analyzer 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.

I 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 - over 147dBc/Hz just 10 kHz away,
much, much better than any Signalhound analyzer (and also a resolution in mHz, if is it needed)!
Regards

[nctnico]

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.

Which was my point. You need a high end machine. 

Yes 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.

From what I've read the Signal Hound software also likes a PC with a hefty CPU to work conveniently.

[G0HZU]

I 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!

The 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.

[bozidarms]

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" ?

[worsthorse]

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.

What is it that you need to do that the one you have doesn't support?

That'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

[hendorog]

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.

Which was my point. You need a high end machine. 

Yes 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.

From what I've read the Signal Hound software also likes a PC with a hefty CPU to work conveniently.

I'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.

[G0HZU]

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.

Compared 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.

[usagi]

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

i 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.

[worsthorse]

That post is terrific. Thanks for doing the work. I need to spend some time looking at the field now...

[Mechatrommer]

May be this one ?
http://www.deepace.net/shop/kc901s/
Sent from my iPhone using Tapatalk

just 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.