[BC] KDKA

[PeterH5322@aol.com]

>I have heard some say the design just does not work. 
>That's hard to believe with the amount of field you can generate.

Only 431 mV/m/kW at 1 km out of 280 degrees of height is poor by any 
measure.


>The 
>close in self fading seems hard to get one's hands around 
>objectively.

The 300 degree WHO design, which has to be considered a complete success 
(it even has its own "Sect" code in the FCC's table of algorithms) was 
specifically intended to be "anti-fading".

That KDKA could not achieve anti-fading behavior whereas the tower's 
height is consistent with that of a proven anti-fading design (WHO's), 
save for 20 degrees (about 53 feet, on 1020), indicates the KDKA design 
is at least flawed if not fatally flawed.

KDKA generates 431 mV/m/kW at 1 km for 280 degrees, whereas WHO, only 20 
KHz higher (which is actually irrelevant), generates 471 mV/m/kW at 1 km 
for 300 degrees.

That's 70,800 W out for 50,000 W in for KDKA and 84,000 watts out for 
50,000 W in for WHO.

280 degrees on 1020 is about 745 feet, while 300 degrees on 1040 is about 
785 feet.

Comparisons of this specific type may be apples (1020) to oranges (1040), 
but the fact remains that WHO's half-century old design was considered 
worthy of being completely rebuilt "in kind", while KDKA's original 
design was abandoned, and its replacement was apparently no better than 
that which it replaced.

As to "... close in self fading seems hard to get one's hands around 
...", I think it comes back to "first principles".

The WHO design was a success, as were several Franklins, and these share 
one defining characteristic: the top section is 180 degrees, although the 
bottom section may be shorter, perhaps as short as 120 degrees.

WOAI's 120 over 120 was a apparently a technical success, but, as always, 
maintenance can be a deciding factor in retaining or proposing a 
sectional, and its new radiator is a ho-hum 195 degrees, with 400 mV/m/kW 
at 1 km.