HP 8591C Cable Analyzer - Page 1
Forum section: electronics / testgear

author: Xnke
author_rank: Regular Contributor
timestamp: March 08, 2020, 06:50:19 pm
content: Looking at getting a SA for amateur radio and RF work-mostly characterizing filters and checking for spurious emissions. Doesn't have to be elaborate, I have limited access to a very nice spectrum analyzer if I need it, but it'd be nice to not have to use it all the time.There are plenty of HP859X SA's on ebay often enough, and most of them go just over my budget, or are very broken. Except the 8591C Cable TV analyzer. I see them sell for as little as 300 bucks, because of the 75 ohm inputs and the 1Mhz to 1.8Ghz range. I rarely need anything less than 1.5Mhz in an SA, so the low end not going to 9Khz doesn't bother me, and I can live with the 1.8Ghz upper range-if I need to go higher I can ask to visit the lab with the 40Ghz SA for a bit.So, if I was to acquire a working, decently closely calibrated 8591C Cable TV Analyzer, it would have the following options that I'd like to change:75 ohm inputs/outputs via option 00175 ohm tracking generator via option 011From some limited googling, people have done this by changing the front panel connectors, exchanging two resistors on a board for the input impedance match, and using a 75 to 50 ohm minimum loss pad for the tracking generator impedance match.Has anyone else done this? The -C units have some useful hardware for filter measurment and noise figures programmed in by default, as part of the CATV personality, but getting good quality test leads and probes for SA use is much easier with SMA or N connectors. (Also, having lived the life of a CATV installer and using BNC's for satellite link work, I have to say I prefer the threaded connectors.) On the other hand, BNC's are designed to have a few more connection cycles by nature of the quick-disconnect coupling-so it's really just the 75 ohm impedance issue.Other options might include an E4401B if I can save up some more money, or wait another year and get the one of the Siglent units. the tracking generator is pretty much a requirement, which pushes the cost of the siglent up into the range of buying a used HP/Agilent

author: tautech
author_rank: Super Contributor
timestamp: March 08, 2020, 07:44:22 pm
content: The SSA's are nice in that you can correct for 75 ohms within the UI however I've grown to like the SVA range more for their additional capability and of course touch display and mouse/keyboard control. They also negate the need for an external coupler for most other work which in itself is an additional saving. Add to that they can do all the TDR stuff making them a pretty powerful tool.

author: GMJ
author_rank: Newbie
timestamp: March 22, 2022, 03:36:48 pm
content: I'm a little late with this, but the 8591C, the input Z is selectable, 50 or 75 ohm in page 2 of the amplitude menu. Also, in "Mode" you can select "spectrum analyzer", and in amplitude you can select amplitude units like dBm or dBuV etc. Yes, it is I believe an 8590 spectrum analyzer with all the good stuff. Mine is like new, must have never been sold. They have a memory battery that has a projected life of 10 years but mine was 20 years old when I changed it and still good. Follow the procedure before changing to back up calibration settings but there is a large capacitor on the board that holds up the battery circuit.Mine does not have option 130, narrow bandwidth resolution, and my minimum bandwidth is 1 kHz. I've been trying to find out if the option is software or hardware or if available anywhere. Field install is option R30 and the part number for the kit is 5063-0246. Great analyzers! I have a Siglent SVA but still love the old analog CRT display, especially in scopes. I call them "infinite sampling rate" scopes.