[BC] And Eugene, too: 50kw KPNW 1120 Off The Air

[PeterH]

On Jul 7, 2009, at 8:30 PM, k7cr wrote:

>A quick geography lesson for you guys-
>KPNW's transmitter is located South of Eugene.
>Eugene is NOT Portland, nor is it even close.
>Take a look at a map it's 110 miles south of
>Portland.

It's located just south of Goshen, OR. Actually, about half-way
between Creswell and Goshen.

If traveling N, look for the Dillard Road off-ramp of I-5 and look to
your left.

>  I have no idea of what kind of transmitter they
>  were running.  I was there about 30 years ago
>(or more) and they had a relatively new Ampliphase.

A BTA-50H, according to memories, which was indeed relatively new
when that station first took to the airwaves in the late 1960s.

Interesting site plan and array design.

Apparently the consultant was given a relatively wide site (E-W), but
one which was rather small in the other dimension (N-S).

Therefore, the 4-tower parallelogram was compressed so that the two
inner towers are about 45 degrees from each other ... and the Tx is
located between these two towers.

And, all towers are 180 degrees tall, which presents some mechanical
and mutuals challenges.

A more modern design would use three towers in an asymmetric inline
to achieve the slightly asymmetric cardioid which is required (one 
co- channel Class A and a first-adjacent Class A).

A lesson could be learned from KEX's array, which has some of the
same issues of asymmetry (but it has two co-channel Class As and the
FCC monitoring station to contend with).