Towertalk
[Top] [All Lists]

Re: [TowerTalk] current balun question

To: towertalk@contesting.com
Subject: Re: [TowerTalk] current balun question
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
Date: Fri, 10 Mar 2017 21:02:30 -0500
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Doesn't the added inductance of a choke that covers 80, or 40 also add more than just the length of the coax?

73, Roger (K8RI)


On 3/9/2017 4:57 PM, Jim Brown wrote:
On Thu,3/9/2017 1:47 PM, Dave Clemons wrote:
I am suspicious that doing so would cause the coax lines on the parasitic elements to no longer be the proper length for 153.45 degrees,

Yes

acting sort of like a loading coil.

No, but screwing up the phasing. Putting it simply, the total length of coax in each feed must be that 153.45 degree length, including any coax that you coil up.

Am I correct to assume this would be a bad idea?

Yes, for that reason and also because a coil of coax is NOT an effective "current balun." What's often called a "current balun" is really a common mode choke. Study k9yc.com/RFI-Ham.pdf to understand why that coil of coax is a lousy common mode choke, and to see several options for GOOD common mode chokes in the Choke Cookbook.

73, Jim K9YC

_______________________________________________



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


--

73

Roger (K8RI)


---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


_______________________________________________



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

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