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BNC connectors in 50 and 75 Ohm cables


autir
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No.

I can't see a rational reason for the existence of the "standard cable TV" connector pair. It's a very cheap and poorly thought-out implementation for any consumer electronics device.

I replace all 73/75 ohm "F" connectors with BNCs, since that simply makes it much easier to make and break connections, and the connection quality is much better. :D
Of course, having a box of male & female BNCs, that I would otherwise have no use for, in the garage, helps. ;)

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These are what I'm using:
http://www.pomonaelectronics.com/pdf/d6702_003.pdf
http://www.pomonaelectronics.com/pdf/d_ai_5079_2_01.pdf
http://www.pomonaelectronics.com/pdf/d5348_1_01.pdf

I see now that the connector purchased was a 50-ohm connector. :P
It won't hurt for 4 or 5 intervening connections, but they do have a cumulative effect; so, if you're going for standard TV and best-practices, or a more complex HDTV setup, you'd want to go with the 75-ohm connectors.

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  • 2 weeks later...

Problems problems problems.
I visited two respectable stores.
The salesman in the first shop told me that there are no 50- and 75- ohm BNC connectors. There is one type of connector which accepts all types of cable (regarding resistance values).
The salesman in the second shop told me that the 75-ohm BNC connector exists only in the crimp model, in order to allow crimping of 75 ohm cables with thick wiring. The screw/solder model of the BNC has no such problem, so comes in one model.
I am all confused...

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Salesmen! ::) They rarely know anything about the things they sell.

The first salesman was a simple waste of human flesh.

The second salesman was talking (politely phrased) out of his posterior.
It's more likely that the shop you went to has only one BNC connector style in the proper impedence. Most pedestrian 75-ohm cable is in the aluminum-shielded variety, for which the crimp-style connector will be needed because I still don't know of a realistic procedure for soldering aluminum shields to anything.

75-ohm cable can be had in copper braid shielding styles, but it's not as common, and the center conductor is usually stranded. It is for this style of cable that the solderable connectors are intended.

If the cable you have is the run-of-the-mill aluminum shield type, then you're stuck using the crimp-installed BNCs.

Please suggest to both salesmen who gave you "advice" that, they would be better-off considering a career in used car sales. At least the customers expect to be lied to, in that type of setting.

Yeah....it may be best to let it go for right now. ;)

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