Vintage vs Modern SA - Page 1
Forum section: electronics / testgear

author: JLM
author_rank: Contributor
timestamp: February 02, 2014, 02:48:56 am
content: I am about a year into hobby electronics and building my lab. I just bought a circa early 1980s HP 8568b spectrum analyzer off eBay. I'm a bit taken aback and the size and weight -- and it's two huge units! It seems to be working just fine, but I am wondering if I am better off with a rigol or other modern SA. I don't really care about the panache of HP/Agilent. I am sure I can get my $900 back by reselling it on eBay. I am a bit turned off by the small, monochrome CRT. So from a feature, accuracy and usability standpoint, should I stick or switch?

author: amiq
author_rank: Regular Contributor
timestamp: February 02, 2014, 03:09:28 am
content: The Rigol has about 30dB worse phase noise than your HP. The HP also has better screen resolution.

author: Fsck
author_rank: Super Contributor
timestamp: February 02, 2014, 03:23:33 am
content: it also cost a small fortune back in the day. the Rigol costs peanuts in comparison.that hp had an msrp ~43k

author: Pasky
author_rank: Regular Contributor
timestamp: February 02, 2014, 03:49:20 am
content: Quote from: Fsck on February 02, 2014, 03:23:33 amNot a fair comparison considering 1MB hard drives were $4k in the eighties.

author: Fsck
author_rank: Super Contributor
timestamp: February 02, 2014, 04:05:30 am
content: Quote from: Pasky on February 02, 2014, 03:49:20 amtest equipment's a bit different. the 3458a came out in the late eighties as well. I don't see the 20+ something year improvement on it.

author: sacherjj
author_rank: Frequent Contributor
timestamp: February 02, 2014, 04:54:04 am
content: Quote from: Fsck on February 02, 2014, 04:05:30 amCompare it to a $43k SA today. Then I'm guessing you'll see a 20+ year improvement.

author: VK5RC
author_rank: Unknown
timestamp: February 02, 2014, 10:59:17 am
content: I would go for the HP unless space/weight is a major consideration, I think the 8568 is one of the SAs supported by John Miles KE5FX suite of programmes that can allow computer conrol of the SA via HPIB via Prologix GPIB-USB interface, this allows quite reasonable phase noise measurement (if you are interested).The HP would prob offer better return on money if/when you upgrade (don't we all!)The suite of programmes also has a printer/plotter simulator and gets really nice print outs of test results if the screen annoys too much.While the HP, due to age is more likely to need repair in the near future, it probably has more standard components and a better manual if you plan to hold on to either for a while.Either way sounds fun!

author: G0HZU
author_rank: Super Contributor
timestamp: February 02, 2014, 01:45:46 pm
content: It depends what you want to do with it. Casual hobby use or fairly serious RF design/verification work? The Rigol would never get into our RF lab at work because it's a low cost hobby analyser with very ill defined performance and high measurement uncertainty. Plus it has very poor phase noise and linearity. By contrast the HP8568B is a very capable analyser even today. Of course, it can't compete against modern DSP for things like log range and accuracy and overall measurement uncertainty but you can still use one for fairly serious RF design work.But for home/hobby use the tables are turned. The HP8568 is huge, heavy, very power hungry and makes a lot of fan noise. Most hobby users won't know or understand (or care) about the difference in RF performance. But they will like the portability of the Rigol plus they will like the modern connectivity and the nice, big colour screen.So for most users I would say to go with the Rigol. You can also get a tracking gen option with it that has awful RF performance compared to lab grade equipment but will be fine for most hobby use.The HP8568 is a fabulous piece of engineering and represented a huge step change in the way the top analysers were designed 35 years ago. It was designed for ATE use and the cost justification for it was that it could replace a human test engineer as it could be operated remotely from a computer. It would be faster, more reliable and could work around the clock on a production line.So despite the massive initial cost and OTT RF performance it could be used for mundane production line testing and pay for itself very quickly. So loads of them were sold despite the huge cost. Often the fabulous RF performance wasn't needed because it was the versatility of the remote control operation that made the sale compared to the cheaper and lower performing analysers. This is partly why you see so many of them on ebay compared to other analysers. HP sold loads of them!

author: G0HZU
author_rank: Super Contributor
timestamp: February 02, 2014, 06:11:55 pm
content: QuoteBe afraid if you venture away from the HP8568B in the used market if you want maximum bang for buck. There isn't much else that can compete on this basis.The Rigol is a contender to the HP8568B for hobby use because it is new and has the nice display, the modern connectivity and the portability etc but this is all at the expense of RF performance.But there is a whole list of popular used spectrum analysers that I wouldn't allow bench space because they are effectively obsolete by today's standards. i.e. they can't compete on RBW, phase noise, log range or detector technology despite maybe costing >$20k when new.Eg I would run a mile from any of the very popular HP859x range of portable analysers from HP. They look nice and look very similar to the 8560 series models but the 859x range are mainly aimed for field service work where a technician measures some very basic RF/EMC results and logs the results in the onboard memory. Hence the crappy 70dB log range on the display and poor phase noise and limited choice of RBW and detector modes.Also, be wary if you buy a used spectrum analyser that is made in Japan. eg Anritsu or Advantest. Some of them have great RF performance are often built better than anything from HP but they are comparatively rare and spares will be hard to find if they do go wrong.Probably the best thing to do is give the Rigol 815 a test trial. See if you can visit someone nearby who has a Rigol 815 to see if you value the modern aspects of its design (and the portability) over the virtues of your current HP8568B