Longest desktop instruments (in a home lab)? - Page 1
Forum section: electronics / testgear

author: Faranight
author_rank: Unknown
timestamp: July 20, 2024, 10:14:07 am
content: Hey, a bit of an odd question, but what is the maximum instrument depth that one can expect to have in a home lab? I'm currently trying to dimension some workbench shelving for my instruments, and I'm having trouble deciding how much space to reserve. I already have a number of lab instruments (PSU's, scopes, DMM's, freq gens, a programmable load, etc), and my current longest instrument is the DMM6500 at about 400 mm plus some space for cabling in the back. I already made the mistake of going for 300 mm shelving, but that was before I got the DMM6500 and I had to plan a redesign. I'm not a professional electronics person, but I do love electronics as a hobby very much, and I see myself getting a desktop VNA, a frequency counter and maybe some other instruments in the future.Is 400 mm deep shelving a reasonable choice?If you have a desktop (not a rack) instrument that is longer than 400 mm, which one is it and how long is it?

author: nctnico
author_rank: Super Contributor
timestamp: July 20, 2024, 10:22:01 am
content: 40cm is minimum; most equipment will fit on a 40cm shelve but also make sure to get a couple of meters of 50cm shelve to store larger (older) equipment. That should get you going for 99% of the equipment. I do have a large DC load which measures 65+ cm but that just sits on top of a storage trolley by lack of a better space.

author: factory
author_rank: Super Contributor
timestamp: July 20, 2024, 10:27:02 am
content: I've got several HP scopes that are approx 2ft in depth, one of them is solid state (except the CRT), perhaps some Tek scopes were longer.The longest one is kept on top of a filing cabinet.David

author: Rydda
author_rank: Contributor
timestamp: July 20, 2024, 10:48:12 am
content: I have a couple that are 410 mm deep excluding knobs. But don't forget the mains power connector/cable, which can add 50 mm (depending on type).

author: Fungus
author_rank: Super Contributor
timestamp: July 20, 2024, 11:07:46 am
content: Quote from: Rydda on July 20, 2024, 10:48:12 amYou can buy right-angle adapters for them but even so it's something you need to take into account.nb. Many devices have things right next to the power socket which means you might need right-angle adapters that go upwards.(eg. Fuse holders, power switches, other connectors...)https://www.aliexpress.com/item/1005006467279256.html

author: tggzzz
author_rank: Super Contributor
timestamp: July 20, 2024, 11:25:11 am
content: Quote from: Faranight on July 20, 2024, 10:14:07 amYou may well end up with equipment designed to fit in a 19" rack.

author: Fungus
author_rank: Super Contributor
timestamp: July 20, 2024, 11:45:47 am
content: If you don't know what's in your future then build for what you have today. You can always screw on an extra piece of board that sticks out a bit if you buy something longer.It's not pretty but it works.It's no worse than building the entire shelf too deep today.

author: m k
author_rank: Super Contributor
timestamp: July 20, 2024, 12:28:21 pm
content: My best places have had shelving away from walls.Current place is narrow with one big table and almost all walls filled with cabinets.Far from optimal.Current setup is based around the table.I'm sure few smaller column style tables would be better.Wide drawer under a table is not bad either.

author: themadhippy
author_rank: Super Contributor
timestamp: July 20, 2024, 12:54:04 pm
content: Quoteon my bench theirs a measurement instrument thats 7.5M long.

author: factory
author_rank: Super Contributor
timestamp: July 20, 2024, 01:07:08 pm
content: But what is the depth of it? as the OP asked;Quote from: Faranight on July 20, 2024, 10:14:07 amDavid

author: AVGresponding
author_rank: Super Contributor
timestamp: July 20, 2024, 01:29:22 pm
content: Quote from: themadhippy on July 20, 2024, 12:54:04 pmOnly 7.5m? I have a 10m one...

author: Stray Electron
author_rank: Super Contributor
timestamp: July 20, 2024, 02:05:00 pm
content: Quote from: Rydda on July 20, 2024, 10:48:12 amThis! And FWIW When I'm out scrounging electronic surplus I grab every power cord that I can find that has a right angle connector (on either end!) and I save them for use in tight spots. A lot of the HP scopes and analyzers and such have the power connector in the back but they're also made to sit face up, on the floor so a power cord with a straight connector will not fit. Conversely sometimes I need to plug a cord into an AC outlet that located behind a book case or other piece of furniture so the cords with the right connector on the male end of the cord are also necessary.Some of the HP equipment such as the HP 1740 and 1727 scopes are quite deep! (You'll have to look up the exact depth) So you might want to plan for things like that. Those scopes also use a power connector on the back (i.e. the end opposite the face) so you'll need to allow extra room for the power cord, even if you use a right angle one.

author: tggzzz
author_rank: Super Contributor
timestamp: July 20, 2024, 03:05:49 pm
content: Quote from: themadhippy on July 20, 2024, 12:54:04 pmI have too many calculators that are 1000"/25.4m long. Too fragile and expensive to have it near my soldering iron, though.

author: Hexley
author_rank: Regular Contributor
timestamp: July 20, 2024, 03:27:22 pm
content: Quote from: Faranight on July 20, 2024, 10:14:07 amThe Rigol DP832A power supply is popular with some folks, and it is 418mm deep. Not including clearance for cables in front and back. Of course most modern power supplies are much more compact. But if you are designing for worst-case, then a 400mm deep shelf might be too little.

author: Swake
author_rank: Frequent Contributor
timestamp: July 20, 2024, 03:27:35 pm
content: Double depth bench: The first 60cm for the work area and 60cm to 80cm extra for the instruments and cabling. Ideally there is some room behind the shelves so that a human can fiddle with the cabling without having to pull everything out. If you often pull the instruments out you can put them on rack style drawers. Those computer screen moveable arms are nice for scopes or for a soldering iron / hot air gun.Keep in mind that your arms have also a limit in length, and you want to be able to reach those instruments comfortably.Exploit the room under the bench: I've got a small rack on wheels with some heavy power supplies. It sometimes servers as a bench extension too.

author: nctnico
author_rank: Super Contributor
timestamp: July 20, 2024, 03:40:41 pm
content: IMHO 80cm is a good depth for a bench. I second the suggestion to leave a slot (say 5cm) so you can run cables at the back of the bench instead of the front or on the bench. On my bench I have mains outlets and slotted cable trunking underneath the desk to keep cables from the floor.

author: DaJMasta
author_rank: Super Contributor
timestamp: July 20, 2024, 06:26:31 pm
content: I use about 45cm deep shelving behind my bench, and yes there's an electronic load and some RF gear that overhangs a bit, but you leave some space behind for cabling (ideally, space to walk, it's tight work back there), and you set the middle shelf height to about the same or just over the height of your workbench, that way you can use a shorter workbench and just have shelves with the gear behind it. I think a 4' (1.2m) deep bench or so would be preferable still, but I was able to get one tall shelving unit and make two half height shelves with two tiers each, so I can get a good bit of equipment behind my more standard depth bench.

author: Smokey
author_rank: Super Contributor
timestamp: July 20, 2024, 08:54:53 pm
content: I used 18in (457mm) depth shelves for my bench. That works great for the stuff I have and my setup.The deepest thing I have is an HP6625A at 20.4" (518mm). It overhangs a little in the back, but my racks are attached to the bench, not the wall so it's all fine.https://www.keysight.com/us/en/assets/7018-03377/data-sheets-archived/5991-0033.pdfThe shortest thing is the scope at 122mm, which actually sucks a bit since I want that central on the bench and it makes it hard (impossible) to stack anything on top of it. I built a little bridge shelve that sits over the scope so I can put the normal depth function gen and counter over it.

author: artag
author_rank: Super Contributor
timestamp: July 20, 2024, 09:12:06 pm
content: An HP16500C is 500mm deep. I think there are a few other instruments of that size and they're post 2000, not antique imho. Any later models that take the expansion cards from the back will be just as deep, but I think some take them from the side, which helps.Even a keithley 2000 is 360mm so I would have some shelves at least 400. I have several shelves that are 500 deep and I butt some right up to the desk so things can overlap shelf to desk if needed.My present scope is only 150mm but has a pointy top so nothing can stack on top of it. But it sits on top of a 350mm deep 19" wide power supply. This only works if the scope is LCD.Update :A friend's HP11848A is here, though it isn't in my bench stack. That's 600mm deep and needs to be racked up with a load of other instruments.Of course, most of these can be rack mounted, sometimes in pairs /quads (quarter or half-width). But they're sold ready to be put on a bench, with feet etc. You can't really discount all the instruments that are wide enough that they have conveniently been provided with the option of fitting rack ears.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 21, 2024, 05:15:40 am
content: If you have the room, allow for instruments that are 80cm deep PLUS a working area in front of them, especially if you might be picking up older used equipment.My bench is 85cm front to wall (has a 5cm gap at the back to allow for cables/plugs), so although it sounds a lot, it is too small.If you can have a bench at least 120cm deep, you will appreciate the working space, if you don't need that much depth you can always pull instruments closer on the surface, I really wish my bench was about 120cm deep.As for shelving, I found 40cm is bit too shallow, it is OK for most things but 50cm would be better, for instance I have a modern Siglent SDL1030X DC electronic load that takes up my entire 40cm shelf and is pushed up against the wall, and I also have a R&S CMU200 that overhangs my 40cm shelf, its front feet dont even touch it, that needs a 50cm shelf.

author: Faranight
author_rank: Unknown
timestamp: July 21, 2024, 06:38:45 am
content: Dang, some of you guys have pretty long.... *ahem*.Anyway, a while ago I bought a standard 90 cm deep laminated kitchen fiberboard and mounted it on top of a custom metal frame that I'm now using as my current workbench space. It was placed against a wall, and the space was plentiful, but then I decided to add some shelving. Having 40 cm shelves with 5 cm spare space in the back for cabling gives me another 45 cm of free work space, which I figured isn't a lot. Using shelves any longer than that will give me even less workspace, so I have a bit of a dilemma here. Since I'm already stuck at 90 cm, I think I'll go for 40 cm shelves. I would have bought a larger board, but 90 cm were the deepest laminated kitchen particle boards that I could find (it's a standard dimension here in EU).I originally planned to have instruments on the first shelf at eye-level, but it seemed a bit too low and didn't leave much vertical space underneath. But then I've seen some people design their workbenches in a way where two shelves of different lengths are used (see pic below). The bottom shelf is very short and is used for shorter instruments like scopes - it rest slightly below the eye level and leaves plenty of available workspace in front. The next shelf is at eye-level or slightly above, and hosts deeper instruments like PSU's, DC loads, etc.

author: guenthert
author_rank: Frequent Contributor
timestamp: July 21, 2024, 06:47:53 am
content: Most people who receive a -hp-3456A moan about the depth of the meter. It's 20.75" (527.1mm) deep, so most modern instruments will be less methinks.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: July 21, 2024, 09:10:00 am
content: My shelving is setup so the lowest shelf above the bench is 30cm, so it does not get in the way of the bench, the shelves above that are 40cm.

author: AVGresponding
author_rank: Super Contributor
timestamp: July 21, 2024, 10:34:03 am
content: Quote from: guenthert on July 21, 2024, 06:47:53 amYeah, my HP 8570A is 570mm deep, and you should always factor in some space behind for routing cables and a bit of ventilation.The other thing with modern instruments is they are alotlighter, so you don't need a massively reinforced bench to carry a full basic set (ie scope, SA, sig gen, DMM, LCR, PSU, load, and not forgetting you need multiples of each, really...)

author: pdenisowski
author_rank: Super Contributor
timestamp: July 21, 2024, 02:32:53 pm
content: Quote from: nctnico on July 20, 2024, 03:40:41 pmDiscerning followers of my behind-the-scenes "test and measurement fundamentals" Instragram may notice that my entire "bench" is one single 29x29 inch (72x72 cm) wooden table. SeriouslyI've never had an instrument that was too long to fit safely on my table (and I have probably had literally 100 different instruments on that table), so I would second the recommendation of 80 cm.https://www.instagram.com/pdenisowski/

author: PwrElectronics
author_rank: Regular Contributor
timestamp: July 21, 2024, 02:59:41 pm
content: The longest thing on my bench is a Fluke 8840A at about 38cm with a tight fit to the wall in back with the front hanging over the edge of the shelf a bit. The longest gear I have is probably my 1956 Tek 531 scope but it sets on a cart and is almost 70cm. My more modern scopes with LCD screens are shallow of course.Unlike some, my lab space is really modest and the bench is just some kitchen countertop with a back splash setting on file cabinets. A raised shelf along the back. During the pandemic when I was WFH, I did all my board level testing on the last project there.

author: David Hess
author_rank: Super Contributor
timestamp: July 21, 2024, 05:09:32 pm
content: The longest common standard is 19 inches or effectively 500 millimeters, but before that, 24 inches or 600 millimeters was possible in older test gear.

author: joeqsmith
author_rank: Super Contributor
timestamp: July 21, 2024, 05:39:03 pm
content: Quote from: Faranight on July 20, 2024, 10:14:07 amMy old LeCroy scopes are roughly 25" or 635mm deep. But you better make sure that you include space on the back side for plenty of air flow.

author: artag
author_rank: Super Contributor
timestamp: July 22, 2024, 02:43:56 pm
content: Quote from: TheDefpom on July 21, 2024, 09:10:00 amMy bench is a standard twin-pedestal office desk, but I have adjustable shelving on the wall behind and to the left of it.The left shelves are all 500mm and the first one is at the same height as the desk. The rear ones vary, and have an odd arrangement where the first, at bench height, is 300; the second at slightly above the top of a computer monitor is 400, the third is 200 and used for small books, while the top is 300 and used for large books and folders.This allows fairly large instruments to my left, a monitor that's off the main desk surface, and the larger books well out of the way while the smaller ones are accessible. The desk, but for the bottom-level instruments and the monitor, is effectively 2m x 1m. It's more crowded thanm I'd like, partially due to my poor tidiness but it does allow a lot of flexibility without any custom building.The desk has small devices such as a soldering station but the only instrument that intrudes on it is the fron half of a logic analyser : the back is on the rear shelf, so it only uses a corner of the deskspace.

author: johnk0gcj@gmail.com
author_rank: Contributor
timestamp: July 22, 2024, 06:28:16 pm
content: HP Agilent quotes my 5342A microwave range counter as being 498mm(19 5/8") deep.

author: TheSteve
author_rank: Unknown
timestamp: July 22, 2024, 06:37:24 pm
content: Anritsu has several signal gens that need 600mm minimum. When I had one on my bench it got a corner and was hanging off the back a little.