[BC] XETRA revisited

[PeterH5322@aol.com]

>As I recall, the AM was 4 towers, one negative. Two patterns. The night
>pattern pulled the signal toward the coastline. I remember people in Yuma
>complaining about us disappearing after the pattern change.The transmitter
>was a Continental 317, Serial #1 and the auxiliary was a GE.

690 is a Canadian clear channel, with Mexico having secondary rights.

>From archive data ...


Canadian: Class I-A, CBF, Montreal, PQ

Old radiator: 409.6 Mv/m/kW at 1 km, ND-2 (G probably about 200)

Present radiator: 364.1 Mv/m/kW at 1 km, ND-2 (G probably about 175)


Mexican: Class I-B, XETRA, BCN

Day array: G=90, S=230, B=81

1: 1 /_ 0 (West tower, and reference)
2: 0.784 /_ 0 (East tower)

Night array: G=90, S=130, B=154

1: 0.373 /_ -29 (North tower)
2: 0.812 /_ 166.5
3: 1 /_ 0 (Center tower, and reference)
4: 0.812 /_ -166.5
5: 0.373 /_ 29 (South tower)

DA-2

Day pattern shape: Modified clover-leaf, with maximum radiation NNW/SSE, 
but with significant radiation WSW/ENE (Arizona)

NIght pattern shape: Figure-8, with maximum radiation SSE, but with 
significant radiation NNW (Los Angeles); nothing WSW (Pacific Ocean) or 
ENE (Canada)

Note: XETRA provides significant protection to the Canadian Class I-A, as 
one would expect as it's a station of lesser class, so it was possible to 
"drop in" a U.S. Class B one (U.S.) state over, in Northern Arizona.