Tweakers' Asylum

Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ.

Use this form to submit comments directly to the Asylum moderators for this forum. We're particularly interested in truly outstanding posts that might be added to our FAQs.
You may also use this form to provide feedback or to call attention to messages that may be in violation of our content rules.

You must login to use this feature.

Inmate Login

By default, logging in will set a session cookie that disappears when you close your browser. Clicking on the 'Remember my Moniker & Password' below will cause a permanent 'Login Cookie' to be set.

Moniker/Username: The Name that you picked or by default, your email. Forgot Moniker?	Examples "Rapper", "Bob W", "joe@aol.com".
Password:	Forgot Password?
	Remember my Moniker & Password ( What's this?)

If you don't have an Asylum Account, you can create one by clicking Here.

Our privacy policy can be reviewed by clicking Here.

Inmate Comments

From:
Your Email:
Subject:

Message Comments

Original Message

RE: 50 ohm phono or 75 ohm bnc ?

Posted by John Swenson on January 20, 2009 at 00:42:58:
The 75ohm BNC is definately the way to go. Just make sure its a 75 ohm not 50 ohm BNC.

You CAN tell the difference by looking at them. The 50 ohm has a ring of (usually) white insullator between the barrel and the pin. The 75 just has air. The 50 ohm type are way more popular so most people have not actually seen a 75 ohm version. If you have the two sitting side by side its pretty obvious. If you buy a BNC that explicitely says its 75 ohm you can be pretty sure it really is 75. If it just says BNC and doesn't say 75 ohm its almost certainly the 50 ohm type.

Since you are doing everything yourself just make sure you get jacks plugs and cable that are all 75 ohm and you should not have a problem.

When making a cable make sure the plug is designed for the size cable you are using. There are several different diamter cables available, for short distances it doesn't make mush difference which you use, as long as it fits the plugs! The thicker cables can handle more power (such as radio transmitters, not an issue here!) and generally have lower loss for long runs. For example if you want to run it 300 feet you probably don't want the really thin stuff. But for a couple feet its no big deal.

John S.