[TowerTalk] "different" trap

[Jim Brown]

Right. The gain shortfall is the result of a design that causes the 
elements to be shorter, which reduces their radiation resistance, and 
the inductive loading provided by the traps. It also modifies the 
current distribution in the elements. This is directly analogous to what 
happens in a mobile antenna with a base- or center-loading coil.

There was an excellent two-part piece of research on this published in 
QEX 4-5 years ago, and included careful measurements of field strength 
resulting from various positions of the loading coil and the the use of 
top (capacitive) loading.

73, Jim K9YC


On 11/22/2019 2:22 PM, Joe Subich, W4TV wrote:
> 
> The K7LXC and N0AX test protocols have been independently
> verified and only the Mosley tribanders showed significant
> gain shortfalls.
> 
> Believe what you like but the Mosely shortfall is most
> obvious on 15 meters where the element shortening is the
> most pronounced.  If you want to discount the K7LXC/N0AX
> results, you need to provide a verifiable hypothesis to
> explain the "Mosley anomaly."
> 
> 73,
> 
>     ... Joe, W4TV
> 
> 
> On 2019-11-22 3:39 PM, Glenn Pritchard wrote:
>> That false narrative about high loss is just not true.
>> I’ve been working with traps for over 30 years and have never seen the 
>> losses that those two claimed.
>>
>> Glenn, VA7UO