Towertalk
[Top] [All Lists]

Re: [TowerTalk] 6M Transmission Line

To: towertalk@contesting.com
Subject: Re: [TowerTalk] 6M Transmission Line
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Fri, 19 Jul 2013 08:39:19 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 7/19/2013 7:59 AM, Hector Garcia XE2K wrote:
There is no problem to run the LMR-600 ,  if you are sure you have the 75 ohms version  
you can "adjust" for 50 ohms
There is a simple, but tried and true method for using 75 ohm cable to 
feed a 50 ohm load.  Simply make the 75 ohm line an EXACT multiple of 
half-wavelengths at the operating frequency. This works because the 
impedance transformation that happens in any transmission line comes 
back to where it started every half-wavelength.
Getting the length right is also easy -- put a connector on one end and 
measure the impedance using any antenna analyzer with the far end 
shorted. When it's an exact multiple, it will measure as a short.  To 
calculate the length, use the velocity factor of the coax and cut it a 
little long, then trim until it's right.
73, Jim K9YC
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>