Boxes are overpriced

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,

which should certainly pass if the zinc alloy one doesn't.

Cheers

Phil Hobbs

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

The drawing you linked is definitely not a BNC. Go measure one and you will see it can't be 7.5 mm.

Big or small, the prices still make little sense.

Extruded aluminum cases predate CAD. Any "stock" box does.

Pac-Tec still makes all cases in the USA. There doesn't seem to be any metallic stuff though.

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.

----- Regards, Carl Ijames

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.

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

Tekoenclosures.com

Not sure of the price, they seem to sell direct. They also do powder coating.

Size is another matter.

Cheers

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

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.

-- john, KE5FX

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:

The flanged boxes are especially nice for battery-powered one-offs that nee d to be clamped to a workbench (

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.

-- john, KE5FX

The boxes can be powder coated:

Yep. 1.2 to 2.0 degrees:

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.

On Wed, 11 May 2016 20:15:38 -0700 (PDT), "John Miles, KE5FX" Gave us:

Anything mechanical these days is going to be more expensive than the electronics. Melamine can be your friend though.

water cut.

seems like a lot of work If you don't need to remove the top zap the seams with a MIG or TIG welder 6 or 8 places

same way they put phones in plastic and glass cases.

All the busy traffic in the pi is on the bus to the ram it's balanced and about 10mm long so it doesn't radiate much

it's 15mm to the HDMI connector, pretty much all else is DC

the bezels are optional, you can assemble the case without them

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.

Cheers

Phil

After anodizing? Won't that be nice looking. ;)

Cheers

Phil Hobbs