[BC] Franklin Antenna - KTTO (ex-KREM)

[Peter]

On Sep 12, 2008, at 12:06 PM, Bill Harms wrote:

> My questions are: Why are there three sections for the AM portion?  
> If this is a Franklin antenna, why are the dimensions unbalanced?

A "Franklin" is a sectionalized radiator with a 180 degree top  
section and a 180 degree bottom section (KFBK x 2).

If the height of the sections are not exactly 180 degrees, then the  
radiator is modeled as a Sect 2, a conventional sectional (KSTP x 1,  
179 over 179).

The bottom of the bottom section is usually left ungrounded.

There are several radiators of the "Franklin type" which are not  
Franklins.

Successful Franklin-type radiators include WHO (180 over 120,  
probably grounded through a capacitor) and ex-WOAI (120 over 120,  
grounded through a capacitor).

Likely, the FCC allowed this three-section radiator, after submission  
of current distribution measurements, because it was daytime-only.

(At night, this radiator is sectionalized so that only the bottom  
section is effective).

Although this radiator is 370 degrees tall (a Franklin would be 360  
degrees tall), it is not performing like a Franklin as its field is  
only 431.79 mV/meter/kW at 1 km, whereas a Franklin would be 510 mV/ 
meter/kW at 1 km. Nor is it performing like a 225 degree, which would  
be 440 mV/meter/kW at 1 km.

However, I'm sure the original owner was pleased as 431.79 mV/meter/ 
kW at 1 km with 5,000 watts in is equivalent to 11,750 watts.