HP8591E opinions and advice - Page 1
Forum section: electronics / testgear

author: notaroketscientist
author_rank: Unknown
timestamp: February 06, 2015, 07:26:28 pm
content: The primary application is measuring low level rf at frequencies below 100mhz.I don't believe a tracking generator will be of much use to me.Salesman had mentioned AM/FM demodulation option for which I don't see any use.The two candidates for this application have come down to the DSA815(in which casethe TG is a nobrainer addon) and the HP8591E which isn't mentioned much here on the forum.I would welcome the insight of someone's experience with the HP.I am concerned with reliability of an old instrument and any known pitfalls.The costs are similar about $1300 without TG.

author: nfmax
author_rank: Super Contributor
timestamp: February 06, 2015, 09:37:37 pm
content: I have an 8591E, which I won for GBP 620 on eBay last year. I'm no RF expert, and I bought this instrument basically to learn about spectrum analysers. I have used it to troubleshoot and check some other test equipment, and to investigate some strange behaviour with 434MHz RF modules I have been using. It seems to work OK. The amplitude accuracy is OK as far as I can tell with the various sources and attenuators available to me. The frequency accuracy is OK. I have only caught sight of one response anomaly - sidebands at around +/- 60 kHz appearing at one combination of span, sweep rate and centre frequency.Apart from that, the display is rather unstable until the instrument warms up: I suspect the CRT monitor is going bad. It's still usable, but I found a spare for GBP 25 and will swap it when I need to. If all else fails, there is an external display video output. The built in display is rather small, but quite clear and sharp, if you like green.Mine is a basic unit with no options, so the minimum RBW is 1kHz and there is no tracking generator. The user interface is simple enough, and there are loads of features many of which I have yet to explore. If it matters to you, the interface appears identical to more recent instruments from HP/Agilent. It's fairly large and heavy, but not in the boat anchor class. The fan is not too noisy. It is pretty easy to open and looks OK to work on. You can download the module level service manual and calibration guide. Calibration data is held in battery backed RAM. My unit is about 20 years old, and the battery (a huge lithium cell) still measures 3.6V. You can manually read out some at least of the calibration data and re enter it if the battery needs to be changed. This is explained in the service manual. I haven't been able to get a circuit diagram or component level service information (if anyone out there has one, I'm interested) There are various option cards. I found a fast ADC card, which gives wider bandwidth FFT of the video signals and more display modes, and it was easy enough to fit. It is a portable unit and seems pretty ruggedly built.I hope this is of use - if you have any specific questions I'll try to answer them.

author: notaroketscientist
author_rank: Unknown
timestamp: February 08, 2015, 06:19:26 pm
content: Thanks nfmax.There is a good one NIST traceable calibrated with a new CRT on my list.