50ohm or 75ohm BNC Plugs ?????
- Thread starter fatcat
- Start date
fatcat
pfm Member
I have just taken delivery of of a nice shiny pair os silver plated BNC plugs. I havent a clue how to fit the cable. I have a good idea how to fot the centre peice of wire. But I cant figure the rest. The end where the cable fits has an approx. 2mm hole, the diameter of my cable looks about 4mm.
HELP
HELP
fatcat
pfm Member
Mark
I have tried to link a drawing of it below. http://www.farnell.com/datasheets/35888.pdf
It is identical to the drawing except the hole dimensioned 1.7mm is actually 3mm.
Plug
Thanks
I have tried to link a drawing of it below. http://www.farnell.com/datasheets/35888.pdf
It is identical to the drawing except the hole dimensioned 1.7mm is actually 3mm.
Plug
Thanks
RichardH
Bodging pleb
If it's at all similar to the ones I have (and that drawing kind of makes it hard to tell), then here's what I did (if it helps):
I assume you've got a bag with loads of bits in there:
The connector body
a centre pin
a washer
a rubber washer
a chamfered metal collar
the back of the connector with the nut and a threaded section.
I ignored the washer, then slid the the threaded nut onto the cable, then the rubber washer. Then strip back about the outer core of the cable to expose the shield - trim this back a bit, but keep some exposed.
Trim back some of the inner insulator - about 5mm. Insert into the back of the pin and solder. Put on the chamfered collar - narrow end towards the pin, so it will sit against the exposed outer shield. Offer pin up to the connector - make sure the outer insulation is stripped back far enough to allow the pin into it's correct position - it should click into place. Now tighten up the rear nut.
A couple of (bad) pics:
Showing collar off for lengths of stripping:
Collar in position, ready to be put together:
Hope that helps!
R
[edited for typo]
I assume you've got a bag with loads of bits in there:
The connector body
a centre pin
a washer
a rubber washer
a chamfered metal collar
the back of the connector with the nut and a threaded section.
I ignored the washer, then slid the the threaded nut onto the cable, then the rubber washer. Then strip back about the outer core of the cable to expose the shield - trim this back a bit, but keep some exposed.
Trim back some of the inner insulator - about 5mm. Insert into the back of the pin and solder. Put on the chamfered collar - narrow end towards the pin, so it will sit against the exposed outer shield. Offer pin up to the connector - make sure the outer insulation is stripped back far enough to allow the pin into it's correct position - it should click into place. Now tighten up the rear nut.
A couple of (bad) pics:
Showing collar off for lengths of stripping:
Collar in position, ready to be put together:
Hope that helps!
R
[edited for typo]
fatcat
pfm Member
Richard
Thanks for the info, the photos are very clear. I now understand how it is assembled. My plug is identical to yours, except it only has 3 parts, it doesnt have the washer or rubber seal. I think my main problem is the hole in the nut is smaller than the cable, plus the insulation covering the inner wire may not fit into the centre pin. I will only find if this is so when I cut the existing phono plugs off the cable.
I think I will have to take a drill and file to it.
Thanks for the info, the photos are very clear. I now understand how it is assembled. My plug is identical to yours, except it only has 3 parts, it doesnt have the washer or rubber seal. I think my main problem is the hole in the nut is smaller than the cable, plus the insulation covering the inner wire may not fit into the centre pin. I will only find if this is so when I cut the existing phono plugs off the cable.
I think I will have to take a drill and file to it.
RichardH
Bodging pleb
Scary stuff!
Remember re the centre pin that the insulation doesn't go into it, only the actual wire itself. Looking at my top picture, I had bare wire from 6mm, insulated inner from 10mm, and outer insulation from 17mm.
If the hole in the nut won't take the cable, what about stripping the outer insulation off, then shrinkwrapping to cover the shield? I can pop a bit of shrinkwrap in the post if it will help - just let me know what diameter the cable is. You'll need a heatgun or turbo nutter hairdrier to shrink it (or judicious application of some other heat source).
RichardH
Bodging pleb
I was just thinking of some heatshrink to cover the shielding if the outer insulation was too thick and had to be removed to allow the nut onto the cable - obviously it should still allow the nut to slide up and tighten to the main body.
Topcat - if you're still having probs I have two of "my type" spare. No fancy pants silver stuff though.....
Topcat - if you're still having probs I have two of "my type" spare. No fancy pants silver stuff though.....
fatcat
pfm Member
Richard/Mark thanks for your advice
Yes, I think I have ordered the wrong type. I have discovered that my plugs are for 2.8mm dia. Coax. The internals are not as yours Richard, there is a pin assembly that consists of small pin, and a teflon insulator between a thing that looks like an ice-cream cone with the bottom cut off (thus creating a hole). The insulation of the inner wire goes into the hole, the shielding rides up the cone. The nut clamps the shielding onto the cone. I think I will be wasting my time trying to fit 5mm cable into a 3mm hole and 3.5mm inner insulation into a 2mm hole. I only decided to buy them very quickly on the phone when the girl from Farnell told me the op amps and DILs I had ordered hadnt reached the minimum order value. Next time I order some equipment I will send them back and get the correct type(now that I know what Im doing).
Yes, I think I have ordered the wrong type. I have discovered that my plugs are for 2.8mm dia. Coax. The internals are not as yours Richard, there is a pin assembly that consists of small pin, and a teflon insulator between a thing that looks like an ice-cream cone with the bottom cut off (thus creating a hole). The insulation of the inner wire goes into the hole, the shielding rides up the cone. The nut clamps the shielding onto the cone. I think I will be wasting my time trying to fit 5mm cable into a 3mm hole and 3.5mm inner insulation into a 2mm hole. I only decided to buy them very quickly on the phone when the girl from Farnell told me the op amps and DILs I had ordered hadnt reached the minimum order value. Next time I order some equipment I will send them back and get the correct type(now that I know what Im doing).