December 4, 2015 at 12:54 am #15914
@ Chico. You answered a question for me. KIXI! ON 910! The messy 4 way battle between the 910 stations at night south of Oregon City. San Fran came in strongest, but that, it was KISN 2nd. Salt Lake 3rd. And this 4th station. Never figured it to be Seattle, but now I know. Thanks!December 4, 2015 at 11:31 am #15931
@ DX- Cannot remember when they switched from 910 to 880 exactly, but believe it was mid-80s sometime. I believe they were quite low powered at night and non directional on 910, so that would explain them being mixed into the soup for you. I do remember having to explain to my mom why her station almost seemed to disappear every night at the same time; this would have been around 1980.
Portland is now in their night null.December 4, 2015 at 12:57 pm #15937
Since most west coast 910’s, both the DA-N’s and DA-2’s, will have nulls north and south (sometimes more to the east as either additional protection or a result of the pattern). This makes the area in-between them a total skywave battle and thereby unpredictable.
KISN’s old site had a great ground field. Their new site is not as big in area and the original ground field at the new site not as electrically long. Take that for what its worth. Also, electrically shorter towers have more radiation above the horizon and thus produce more skywave radiation and less groundwave radiation. Towers considerably shorter than 90° produce so much radiation above the horizon that much of the power is wasted into space. Choosing nighttime power is a delicate balance so as to not be a source of skywave interference to the other co channels operating at night.
If you are a real glutton for punishment, this article is quite detailed but also a great primer.December 4, 2015 at 6:04 pm #15950
@ Chico. You asked about other Portland calls that made reference to their associated frequency. The only example I can think of is from the early 80’s. KCNR (97.1) billed itself as The CeNteR of your FM dial.December 5, 2015 at 12:00 am #15961
I show KIXI as 1KW fulltime on 910. Their application for 50KW was granted in 1982 but dates back to 1973, which I don’t quite understand because the FCC hadn’t broken down the clears yet and wouldn’t for several years. The 302 to cover the move to 880 was filed in 1983 but not approved until 1986, due to requests of denial. Shortly after the license was approved, they applied for 10KW at night and were licensed for that in 1987. There was also the matter of a change of community of license to Mercer Island/Seattle, probably one of the last dual city licenses.December 5, 2015 at 12:19 am #15967
Thanks, Semoochie. I am a fan of the station so that is good to know.December 5, 2015 at 3:17 pm #15980
I would be REALLY surprised if KUIK had changed their STL setup from analog…with only a single station to transmit and no need to transmit any IBOC data why fix something that isn’t broken?December 7, 2015 at 5:13 am #16060
Godmam Chico! You are the Mann!! That whine! Always hated that whine. Me as an adolescent boy. Didn’t know. Loved KISN though! Always had to drive north of OC to get them though.December 7, 2015 at 10:01 am #16069
Andy: “KISN’s old site had a great ground field. ”
When you say KISN old site had a great ground field, were you referring to the site on 158th and Airport Way or their “old” site on Smith Lake?December 7, 2015 at 1:01 pm #16073
This is easy to explain, or rather to see. When an AM installation is in an open field that extends away from the tower base as far (or nearly as far or even slightly further than) as the tower is high, then the ground field is the same electrical length as the tower. Although the actual distance (height, electrical height) of the tower is paramount, the size of the ground field is almost just as important to both ground wave and skywave propagation. Some examples of bad ground fields around town are the new KISN site. Originally designed for 1080, and now duplexing a lower frequency of 910. The lower the frequency the larger the wavelength. Worse than that is 620 being duplexed into 1190 at the site designed for 1190. Another hack job would be Pamplin’s 860 being diplexed with 1550 into a site designed for 1480. Up on Mt. Scott, originally designed for 1330 and now carrying 1640 as well, there has been some work done to the old ground field years ago (before 1640) because the ground field had rotted away. The 970 site at Sylvan I just don’t know. It looks big enough to have a good ground field but I don’t know what’s really there. The booby prize goes to Wally H. and the original 1410 site at Healey Heights that was shunt fed and had NO ground field whatsoever.December 7, 2015 at 3:14 pm #16078
I once heard that the KOIN site had a lot of mineral deposits that affected the signal but it could be just “urban legend”, for all I know. Are you saying that they left the old KAAR ground system in place when 1550 moved in? Since the towers are in different positions and more of them, I don’t quite see how that’s possible. Doesn’t the ground system have to extend outward from the base of each tower?December 7, 2015 at 3:32 pm #16082
Not sure but I know they chopped some of the ground radials shorter for residential expansion somewhere along the line. I am fairly certain they did not dig up the whole field for 1550 if that is your main question. The ground field should be centered at the tower base, but it wouldn’t be inconsistent with their shoddy engineering to just re-orient the close in pieces of the lattice to approximate concentricity. The larger and more significant error is using the ground field designed for the right end of the dial for the Troutdale station which is left of center on the dial. The electrical length of the “new” 1550 towers at 860 is not even 82º (less than a quarter wave) and the ground field in my estimation is less then that, since even in the days of 1480 the north south radials were considered too short due to the old property line on the south and 34th ave on the north. In fact the “new” 4th tower (the dogleg to push signal into Troutdale) is so close to 34th that the ground field on its north side is almost non existent.December 7, 2015 at 4:29 pm #16083
Thank you, I can certainly understand how that could have an effect. I was told by CE Oliver Potter, when I worked there that the KGAR towers by I-205 were 3/8 wave and the replacements appeared to be the same height.December 8, 2015 at 1:15 am #16088
I was once told by Herb Davidson (Ex CE of KPOJ-1330, CE of KOIN-TV) that the 970 Antennas at Sylvan and the 1330 towers on Mt. Scott were basically done by the same person. He must have liked putting AM’s on hilltops for some reason. I forgot his name but was an early engineer at KOIN…before my time and television.December 8, 2015 at 3:41 am #16093
Well, you all know by now that I am kind of a nostalgic fool. Like the oldies and the Xmas. Hey, what can ya do? Ya do what gets ya through!
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