Looks like a good lead, thanks. I'll get a couple and see.
Not a huge problem--we can easily make the board a bit skinnier. (It's still in layout).
Might be a bit of a problem with the one I'm using though, which is 15.8 mm. ;)
There's nothing that says the board has to go in right side up, though. There'll be plenty of space on the other side. Good point about idiots using too-long screws!
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
Yeah, I saw that. We'll have to use a slightly taller box then.
I have a whole bunch of dodgy patch cords in a box, and I can test two units per cord. ;)
Tyco makes a phosphor bronze one,
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which should certainly pass if the zinc alloy one doesn't.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
That's a "HD BNC", which is half the size and far less durable.
The bandwidth is only 1 MHz, so that's not a big worry. (It's a TIA with a 1-uA full scale range, so even with a 3 pF photodiode, a sub-nanoamp bootstrap still dominates the noise above there.)
Coax-connectors.com lists a "low profile" one that would probably fit, but there's no drawing.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
I realize that I'm still half asleep, but if the table has an array of threaded holes and the box has threaded holes in the bottom, just how do you attach the box to the table? You mention a post, is that going to have a flat surface with through holes in a spacing pattern to match your box? Seems like Lasse's "wings" would be needed to attach the box directly to the table.
Also, just an idea, but if you used an extrusion that was just a bit wider than the board you could put the BNC hole in the side of the extrusion and leave the end plates plain and thin (and cheap). That way the box itself will resist your RG58 yank test. You just have to be able to insert the board into the box and get the BNC through the hole, then put the nut on the outside to hold the board. Also, that way you only machine on the box, so the end plates never go to the machine shop. An old piece of equipment back in school used this idea for a preamp box. They used an extrusion of rectangular tubing about 3" x 6", cut to 3" long. Had two right angle input BNCs soldered to the board and sticking through one 3" x 3" end and an output BNC and DE9 power connector on the other end on wire pigtails. The board was supported by the input BNCs and four posts pressed into one end plate. One 3" x 6" end plate was just that, and the other was 7" long to provide 1/2" wings with through holes for mounting and had the posts pressed in. So yes, one end plate needs machining but it gives the strongest mount for the BNCs.
Oops. I didn't notice: This is cute: "...there is a Din 1.0/2.3 being referred to as a miniature BNC, a miniature BNC referred to as an HD BNC, and the "common" BNC, which is an HD BNC because it comfortably carries high definition signals."
Try the "downloads" tab on Coax-Connectors.com. Oops 2.0. Maybe not. This looks likely: but the "downloads" has a drawing of the wrong connector. Reverse engineering the URL for the correct part number yields nobody home: The 75 ohm part number 10-466-A8 has the same problem. Argh.
Just to make things interesting, coax-connectors.com has an overkill jack that will fit at 12.55m high: but it's only available in 75 ohms. Argh 2.0.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Trouble with Alibaba and Aliexpress is the worthless search capabilities. There are so many sellers and so little information then on top Ali... just dumps everything together for you to wade through.
There are lots of optical things that have blind holes on the bottom. You mount them on posts or rails or plates or translation stages or things like that.
Not a bad idea.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
I'm not extremely optimistic about the EMI properties of these particular H ammond enclosures. Right now I'm working on a gadget that will go into a 1
455Q2201 (in pre-production form, anyway). They have plastic bezels that n icely insulate the end panels from the extrusion except at the 4 corners wh ere the screws go. In other words, you get 8 slot antennas and two patch a ntennas free with every box.
The BOM is in the low four-figure range so I don't really care whether the box is $20 or $30 or even $50... I just wish there were more options. Esp ecially for those of us who don't have time to haggle with sellers on a Chi nese web site named after a guy who hung around with 40 thieves.
I use a lot of Hammond 1590 boxes for prototyping and general tinkering, bu t they'll always look like something you put together in your basement last weekend. Velleman boxes look somewhat more professional:
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... and they don't have the annoying side d raft that the 1590 boxes have. Some of the Velleman boxes have holes in th e bottom as well (Velleman G106 is the closest to a Hammond 1590B), as well as flanges.
The flanged boxes are especially nice for battery-powered one-offs that nee d to be clamped to a workbench (
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). Not su re if the hole size/spacing would be appropriate for an optical bench, thou gh.
Now that I think about it, I'm not 100% sure I used a Velleman box for that preamp -- it might have been made by Hammond. Both Velleman and Hammond b oxes have optional flanges, and Hammond may be making boxes with straight s ides these days.
Dunno. I quick tour of the catalog showed that all of Hammond's 1590 series boxes have angular sides. However, there may have been some model or 1590 mutation with straight sides.
Incidentally, there are also Bud diecast boxes: Although the sides are not perpendicular, these boxes have the advantage of using a sheet metal cover, which is easier to work with than a cast cover. The disadvantage is that I can only get a reliable ground connection around the 6 or 8 screw holes.
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
bezels that nicely insulate the end panels from >the extrusion except at th
nnas and two patch antennas free with every box.
As I said upthread, I'm not planning to use the cheesy plastic bezels. Ther e's no huge issue with producing EMI--the circuitry is all analog except fo r a 150 kHz Simple Switcher with nice soft edges (LM2594) and a toroid.
The bandwidth is lowish as well, so the main worries are cell phones and ca pacitive pickup directly to the photodiode.
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