[TenTec] OCF antennas evolution

[Jim Brown]

On 7/12/2013 2:40 PM, Richards wrote:
> On 7/12/2013 4:29 PM, Stuart Rohre wrote:
>> To further amplify Rick's comments, an antenna that has gained
>> popularity in USA in recent years, is a 40 odd foot high vertical for 80
>> and 160m work.  One of our North TX hams published his versions in 
>> two QST articles.

The "magic" (good engineering) behind the 43 ft vertical antenna is that 
it is not too close to a half wave, or multiple of half-waves, on the 
major ham bands, so the feedpoint impedance never gets TOO high, and 
it's long enough (roughly 3/16 wave) on 80M to load and radiate fairly 
well.

> In contrast, Rick sold me on the  notion that an 80m inverted-L with 
> appropriate additional capacitance is better than a very short 
> vertical with inductive loading.  (Hopefully not losing too much in 
> such a short translation...)

He is exactly right.  To understand the design concepts, study my 160M 
antenna presentation, on my website, dividing the physical dimensions by 
2.. The ON4UN book also has lots of good stuff on verticals and radial 
systems.

   http://k9yc.com/publish.htm

73, Jim K9YC