[amsat-bb] Re: 75 ohm CATV Cable on 70 cm

[i8cvs]

----- Original Message -----
From: "kc6uqh" <kc6uqh at cox.net>
To: "Mike Miller" <mmiller at nctc.com>; <amsat-bb at amsat.org>
Sent: Tuesday, May 22, 2007 7:46 AM
Subject: [amsat-bb] Re: 75 ohm CATV Cable on 70 cm


> I have used the 1/2 " hardline type with disk type dielecrtric for several
> years. A 1/4 wave of brass hobby tubing driven over the copper center
> conductor and soldered at both ends solves the 50/75 transition problem.

> Art, KC6UQH

Hi Art, KC6UQH

If the diameter of your 1/4 electrical wave long of brass hobby tubing
driven over the copper center conductor changes the impedance of this
cable section from 75 ohm to SQR( 50 * 75) = 61 ohm it is a good idea.

Best 73" de

i8CVS Domenico