WWZN and Kinstar antennas

[Scott Fybush]

Aaron Read wrote:

> However, since WWZN has such a high frequency, I think they may be able 
> to get out of their current location within a few years using the new 
> Kinstar antennas.  Kinstar is not yet FCC-approved for anything but omni 
> AM's but that will almost certainly change once Kinstar finishes the 
> research on it.  They've mostly been focusing on the Expanded Band 
> market which doesn't allow directional patterns, but I'm sure they'll 
> get other people with DA's knocking on their door soon.
> 
> I saw a presentation on these antennas at NAB and it's a remarkable 
> design.  At the high end of the band (down to about 1300-1400kHz) the 
> radiating elements are so short you can use wooden telephone poles to 
> support the four corners of the elements!  We're talking total height of 
> about 50-60ft while maintaining about 95-98% efficiency.  HELL of a lot 
> easier to find a field that can take that can handle poles that short 
> than to find a place to put quarter-wave towers that're still over 100ft 
> tall.
> 
> There's a couple of decent-sized woods/fields less than a mile from the 
> current WWZN site...one over by Bentley College and another by that old 
> military installation.  If directional use for the Kinstar system is 
> approved, I'd wager 1510 could finagle a lease that's a lot more 
> financially attractive at one of those places.   The "towers" probably 
> would be completely hidden by the trees.

The Kinstar is indeed an interesting antenna, and potentially quite 
useful for situations with draconian height restrictions.

I'm not convinced that it would be the salvation of WWZN, though. While 
the existing four-tower array is very closely spaced, and a similar 
array of Kinstars could probably be spaced almost as tightly, there's 
still the pesky matter of a ground system. Yes, the Kinstar means you 
don't need a quarter-wave of steel in the air, but you DO still need a 
full quarter-wave of copper in the ground. (In fact, I'd venture to 
guess that a really good ground system is even more important with a 
Kinstar than it would be with a standard quarter-wave tower.) That land 
doesn't come cheap anywhere that 1510 would need to be.

I'd also be very concerned about the skywave takeoff angle from the 
Kinstar. (Perhaps this was addressed in the presentation at NAB, which I 
was unable to attend.) For a powerful directional 50 kW station at the 
top of the dial, there's a danger of skywave cancellation even during 
the day at relatively close distances. (I get that problem here in 
Rochester when trying to listen to WWKB around dusk. In the summertime, 
it's essentially unlistenable at about 70 miles out because of 
cancellation between the skywave and the strong groundwave.)

There's another, much bigger problem that WWZN would subject itself to 
if it were to make a voluntary move of its night transmitter, and that's 
the FCC's well-meaning but misguided ratcheting rule, which I could 
expand on at mind-numbing length if anyone's interested...

s