HP 8560E SA Option 007 (Fast ADC sweep times), and other ramblings - Page 1
Forum section: electronics / testgear

author: NF6X
author_rank: Unknown
timestamp: February 11, 2015, 10:30:55 pm
content: I'm looking at spectrum analyzers for my home test bench, and I'm presently gravitating towards getting a refurbished and calibrated HP 8560E series rig, probably in the $2000-$3500 (US) range. There's one possible option that I don't fully understand, and I hope that somebody here can help me decide whether I might want it.Option 007 adds fast ADC sweep times, enabling sweep times of 30ms to 50us. When I was previously looking at 859xE series SAs(*) there was a similar-sounding option that was necessary to enable AM/FM demodulation, but it's not clear to me whether option 007 is needed for AM/FM demod in the 8560E. My uses for the spectrum analyzer will include working on AM and FM ham radio gear, so I think that AM/FM demod would be a handy feature to have.So, can anybody explain to me just what I would gain by having the faster sweep times in an 8560E, or conversely, what I would lose by not having it? There's a particular local test equipment vendor that I'm gravitating towards, and at least in his shop, option 007 bumps up the price significantly enough that I want to learn about it before throwing money at it.I've been considering whether I might want a model with a top end frequency above 2.9 GHz, but I'm not positive that I'd actually need that. I do want to at least cover the 2.4 GHz bands, and that alone rules out those nice, cheap Rigol DSA815 rigs for me.I've also been debating whether I want the tracking generator option. On the one hand, it would certainly be convenient. On the other hand, it bumps up the price significantly, I can already sweep filters with a GPIB-controlled signal generator and USB interfaced power detector, and I will probably want to get a real vector network analyzer someday. So, I'm debating whether to get a model with a TG or not.If anybody here can help clue me in about the capabilities gained by the faster sweep times, I'd sure appreciate it. Any other related discussion about these SAs is quite welcome, too.(*) I've moved from considering an 859xE series to considering an 856xE series instead, due to its much narrower available RBW.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: February 12, 2015, 02:47:44 pm
content: Hi,Recently purchased an 8560E. Not sure I can answer your question, but it might make the delay for measurements a bit less, depending on your settings you are using. One thing to be aware of with these SAs is the hours on them could be quite high, as I think mine is (not sure if there is a log somewhere stored). The CRT display on mine is starting to fade, and becoming harder to read. I have seen several color LCD displays to uprgrade these, which I am interested in doing, but shopping price right now.If anyone knows where to get a good LCD display for these, I'd appreciate a link.Almost forgot, the soft keys get dirty/oily on the conductive pad, making keystrokes harder, and harder to input. there is no replacement keypad on these, it's actually part of the front panel assy., so that needs to be carefully taken off to get to the pads for cleaning with 100% IPA.

author: NF6X
author_rank: Unknown
timestamp: February 12, 2015, 03:29:15 pm
content: Aside from the fading CRT, how do you like your 8560E?You might be able to improve the display by readjusting the monitor subsystem, if the CRT itself isn't too badly burned in.I see an aftermarket LCD upgrade kit for the 8560E on eBay for US $1495. The listing states that a lot of soldering on the A2 CPU module is required to install it.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: February 12, 2015, 03:48:43 pm
content: Hi,Not sure if you saw my modified posting on the soft key issue. I like it ok. I use the E4407B on a daily basis at work, and much spoiled by that one. So that's why it's just "OK".the $1495 price is for them to install it I think. Much cheaper, around 500 or so to do the work yourself.I don't mind doing it, but I have seen the displays much cheaper for other equipment.

author: NF6X
author_rank: Unknown
timestamp: February 12, 2015, 03:52:58 pm
content: Thanks for mentioning your post edit about cleaning the keypad contacts, because I missed it.I'm also really spoiled by the test equipment I have access to at work!

author: Mr Simpleton
author_rank: Unknown
timestamp: February 12, 2015, 06:09:04 pm
content: I have the 8560E sans the 007... and quite happy with the performance! Having spent years with the venerable 8568B which we still have the cubicle, I find the performance pretty much the same but sometimes the 8560 seems to stop sweeping for a fraction of a second. Not sure what goes on but it is somewhat distracting. The 8560 was chosen due to its smaller sized vs 8566/8 and beeing somewhat newer too. I got the phase noise measuring option, but find using KE5FX PN program so much easier.I also have the Signal Hound SA44B which is a very neat little analyzer that one can stuff into the laptop bag, and is powered from the USB port. And with the new software released two days ago, it is almost like a new instrument!Both my analyzers are used and I would be hard pressed to pick one as they both have their strenght and weakness.Now if I only could find time to get my lab organized, I could really start having fun... So many fun projects in the pipe

author: G0HZU
author_rank: Super Contributor
timestamp: February 12, 2015, 09:39:09 pm
content: At work we have had lots of HP8560E models over the years. I've always really liked and admired this analyser but I have to say they are becoming very dated now and I have to agree that the ageing CRT and the keypad membrane add to the sense of age when I use one today.The analyser becomes quite irritating to use once the keypad membrane gives issues because the buttons become less and less responsive. Usually it is the up/down buttons that begin to fail first...The CRT display really does look quite tired on some of our examples. We also have the newer version that came fitted with the LCD display but I think these are all 8563 models. I'm not very impressed with the LCD display on these.I don't think we have option 007 on any of our analysers but I assume it allows fast and accurate sweep times in zero span mode. So it may prove useful for looking at fast OOK waveforms or for very crude PLL lock analysis. There's probably an advantage in the regular frequency domain modes too. I don't have one here but I think our 8560E models have analogue RBW filters down to 100Hz RBW and the 30Hz RBW and below are all done in DSP. Maybe 007 improves on this? I can only guess.But the 8560E is a great spectrum analyser. If I was to buy one I'd not bother with option 007 or the Tgen option but I would want the IF output option (it has 25MHz bandwidth) because it would hopefully allow the ability to fit an external homebrew downconverter and ADC/DSP in the future. So I'd be interested to see how clean/stable it would be here in zero span with option 001 fitted.

author: NF6X
author_rank: Unknown
timestamp: February 12, 2015, 10:08:59 pm
content: Thanks! These opinions from folks who have been hands-on with this SA series are certainly helpful!So far I've mostly experienced keypad problems with R&S equipment at work (especially the older gear that we had when we were a starving start-up (starve-up?). I like the UIs on R&S spectrum analyzers and network analyzers, but I feel like HP gear is a better option for my home use since repair manuals appear to be more readily available for them.I'm leaning towards saving money on a machine with neither the 007 nor TG options, now.Is the IF output that G0HZU refers to the one on the front panel (I think it's standard), or the option 001 310.7 MHz IF output on the back panel (I think)?

author: G0HZU
author_rank: Super Contributor
timestamp: February 12, 2015, 10:16:11 pm
content: I think option 001 is the IF2 output option on the rear panel.I think this output will still be 'swept' so to see a fixed output the analyser would have to be set to zero span to fix the LO. However, I'm not sure how much jitter and noise there will be on this output when this is done. So it might not prove to have high performance. But the idea would be to fit an SDR 'IF' here allowing all kinds of demodulation or spectrum analysis in real time.

author: NF6X
author_rank: Unknown
timestamp: February 12, 2015, 10:19:33 pm
content: That option could be pretty useful to me. My USRP has a coverage hole right over the 6m ham radio band if I'm not mistaken, so using the SA as a receive converter could let me do stuff there that I can't otherwise do easily.

author: G0HZU
author_rank: Super Contributor
timestamp: February 12, 2015, 10:22:37 pm
content: A lot of people would choose to have the TGen option because this can be extremely useful.But I've used the TGen option on the 8560A and wasn't impressed with it in terms of tracking with narrow RBW settings. Maybe ours was faulty?But I would always recommend a VNA over a tracking gen and there are various low cost USB based VNA kits available for ham use that have quite respectable performance.They don't work up to 2.9GHz but they will offer much more versatility including the ability to measure impedance and phase response and group delay in filters etc.

author: G0HZU
author_rank: Super Contributor
timestamp: February 12, 2015, 10:24:33 pm
content: Quote from: NF6X on February 12, 2015, 10:19:33 pmI don't know how popular this option 001 is so it might prove difficult to find one... I don't think our 8560E analysers at work have it but I can check.

author: NF6X
author_rank: Unknown
timestamp: February 12, 2015, 10:26:09 pm
content: I think that the seller that I'm engaging with mentioned being able to add 001 at no cost in one of his 856xE listings, so I'll ask him about this. It might be nothing more than adding a cable from an internal connector to a rear panel punchout?

author: G0HZU
author_rank: Super Contributor
timestamp: February 12, 2015, 11:36:07 pm
content: My main concern would be as to how much jitter and noise there will be at the IF output when in zero span. It should be fine for basic spectrum analysis but it could be quite jittery if you wanted to demodulate very narrowband signals. So it might not be what you want or expect.

author: alex.forencich
author_rank: Frequent Contributor
timestamp: February 15, 2015, 07:35:07 pm
content: Option 001 is just a cable as far as I know. I'm not sure what's on the other end of it, though. Would need to check the service manual.As far as tracking generators are concerned, you can get an external tracking source (85644A or 85645A) to use instead of the built-in one - these will go up to 6.5 GHz or 26.5 GHz, while the internal one is limited to the low band, 2.9 GHz. They are a bit hard to find, though.

author: Electro Fan
author_rank: Super Contributor
timestamp: February 15, 2015, 10:25:52 pm
content: A little bit off topic but given that tracking generator discussions have been coming up in this and other threads and some questions have arisen regarding the use of TGs vs sweep generators I thought this might be interesting/useful to some folks.http://www.ke5fx.com/tg8566.htmlWith the addition of a tracking generator, Hewlett-Packard's 8560-series spectrum analyzers can perform scalar network analysis (magnitude of gain/loss across a specified frequency range) of two-port RF devices. Tracking generators are great for tuning filters, determining the usable frequency range of amplifiers and attenuators, and aligning receiver IF stages. Because its output frequency automatically "tracks" the frequency to which the spectrum analyzer is tuned, a tracking generator can make life a lot easier when making swept-frequency response measurements. Unfortunately, tracking sources for the HP 8560-series instruments are still quite expensive on the used-equipment market, and not at all easy to come by.Lacking the right equipment for the job, spectrum-analyzer users often resort to acquiring frequency-response plots with the aid of an ordinary sweep generator. The generator's output is applied to the input of the device under test, and the user observes the network's response on the spectrum analyzer. As with most other network-analysis procedures, accessories such as directional couplers may be used to observe reflected power versus frequency.But this procedure is slow and cumbersome, since the sweep generator's output isn't synchronized with the analyzer's own sweep. It may be necessary to leave the analyzer in "Max Hold" mode for several minutes, waiting for the sweep generator's output to coincide with the analyzer's response at every point on the display. Users of older spectrum analyzers without digital storage are simply out of luck.A microwave sweep generator like the HP 86222A has a lot in common with a tracking generator, but unlike the real thing, used HP 8620-series sweeper plugins are commonly available on eBay for a couple hundred bucks or less. It's worthwhile to explore the theory of operation behind these less-expensive instruments to see what hidden capabilities lurk beneath the surface of their spec sheets! .... (see link above).

author: Electro Fan
author_rank: Super Contributor
timestamp: February 15, 2015, 11:27:22 pm
content: Quote from: alex.forencich on February 15, 2015, 07:35:07 pmThey do seem to be somewhat rare and they are kind of pricey, but setting aside availability and price - and the bandwidth - are there any key differences between the external TGs and the internal 856X TGs in terms of functionality or performance within the supported range? Thx

author: G0HZU
author_rank: Super Contributor
timestamp: February 15, 2015, 11:57:34 pm
content: I've got one of the HP85644A external tracking generators here and it is compatible with my old HP8566B analyser as well as the portable 856x series.HP claim a very high dynamic range when used with the HP8566B. However, it is quite big and heavy and I find it all bit fussy to connect up all the cables to make it operate in TG mode with the HP8566B and this is enough to put me off using it again like this. It can also be used as a standalone signal generator up past 7GHz and the internal levelling circuit means that it is quite accurate in power level and can be adjusted across something like -80dBm to +10dBm.But it isn't synthesised when in sig gen mode so the frequency accuracy is poor and it's very microphonic as well. The external tracking generator is also quite big and heavy and as used items in 2015, they are very overpriced IMO. I bought this one with a lucky low bid on ebay as a non runner. I only had to replace the fuse to repair it so it was a rare bargain for about £175 here in the UK. But in the USA where they seem more common they still seem to fetch many thousands of dollars.So in terms of internal vs external I would definitely favour the internal TG over external even if there may be a slight loss in performance (if any). You save on price, size, power, weight and also convenience.

author: Electro Fan
author_rank: Super Contributor
timestamp: February 16, 2015, 12:43:55 am
content: Quote from: G0HZU on February 15, 2015, 11:57:34 pmYou did great: £175! They don't show up often and when they do people ask >$5k USD; I don't know if anyone pays those prices or if they are just asking prices but I think a fuse plus your unit cost a lot less.So, even it's a but fussy and takes up some space it's all beautiful. Thanks again for the info - enjoy your gear!

author: NF6X
author_rank: Unknown
timestamp: February 22, 2015, 09:14:00 pm
content: Just a brief follow-up: I ended up pulling the trigger on an 8650E with option 001 (310.7 MHz IF output on rear panel) from eBay sellertestcalinstruments. I got it yesterday, and I'm really happy with it. Here are pictures of it on my blog:http://www.nf6x.net/2015/02/hp-8560e-spectrum-analyzer/

author: alex.forencich
author_rank: Frequent Contributor
timestamp: February 23, 2015, 01:03:02 am
content: Quote from: Electro Fan on February 15, 2015, 11:27:22 pmThe 85644A covers 300k to 6.5 gig while the 85645A covers 300k to 26.5 gig. The internal TG only covers 300k to 2.9 gig (low band only). I managed to score a broken 85645A for about $1k that failed self test with an ADC Vref error. Turned out to have been caused by a blown cap and LM317 in the power supply. The generators are quite bulky, but being able to get all the way up to 26.5 GHz is hard to beat. However, the 85645A is rather hard to find, so you may be better off picking up an old VNA if you want to do network analysis.Another thing to note is that you can't use a TG (internal or external) with an 8560 series analyzer below 300 Hz resolution bandwidth (I think...not sure about the exact frequency) as after that point it stops sweeping and switches over to taking FFTs to get the narrow bandwidth. If you need sub 300 Hz RBW with the TG, then you need to use an 8590 series analyzer with the NBW option as this uses analog filters to get down to 30 Hz RBW.