This is what KFBK routinely sounds like up here at night:
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Seattle-Tacoma Area AM groundwave coverage - Crummy in spots.
- Thread starter RF101
- Start date
This is what KFBK routinely sounds like up here at night:
You can also receive 570, 770 and I believe, 820. We used to get 950 but the 940 that's about 30 miles away raised power from 250 watts to 10KW. We don't get 880 because a station 60 miles away went on the air at about the same time.
I’m not sure how listenable it would realistically be in the north sound, but it’s rock solid all around the south sound. I hear it all of the time on my radio over 150 miles north most nights.
Many years ago, 1360 tried a synchronous booster in Mountlake Terrace to become more of a full market signal. It apparently was not a successful experiment.
In the dead of December, KFBK comes in all day long in the Seattle area.
I remember that. (ECHO-CHO-Cho-cho.)
Could the underground volcanic magma associateated with Mount Rainier be a factor in questionable daytime reception? Some EMS planers have nightmares about a possible eruption.
That is a slight factor at best, secondchoice. The main issue this that most of at least the Puget Sound basin is glacial till. Sand and gravel, not much iron at all. Just dastardly stuff for groundwave propogation. Add to this all of the granite and basalt in the Cascades and Olympics and you have some really low scores. The magma chambers are certainly a factor, but even in the active Cascade range they only represent a tiny fraction of the whole mountain range.
This is NOT to downplay the danger said magma presents, as you mentioned. WA alone has four dormant volcanoes and one active - St. Helens. Rainier, Baker, Glacier Peak and Adams all are capable of causing great damage and loss of life- they are just "sleeping" for now. There is active magma under each. There are further dormant cones in OR and BC as well.
This is NOT to downplay the danger said magma presents, as you mentioned. WA alone has four dormant volcanoes and one active - St. Helens. Rainier, Baker, Glacier Peak and Adams all are capable of causing great damage and loss of life- they are just "sleeping" for now. There is active magma under each. There are further dormant cones in OR and BC as well.
Here in North GA. we have crappy ground conductivity too. There is iron in the soil but it does not help ground conductivity. Kinda made Atlanta and "early adopter" of FM.
From my broadcast engineering classes 60 years ago, I learned that AM radio waves are propagated in the topsoil for the most part. That is why the deep topsoil of the Great Plaines has such good conductivity, and the less conductive soil of NW Georgia or much of New England does so poorly.
The Plains can have topsoil that is several meters deep, while some other places have only a few inches... or none. Long Island, a huge sandbar, has land that is about the worst conductor of radio waves in the U.S.
The question is more about how much of that volcanic magma is mixed with the local topsoil, making it less suitable for AM radio.
So the only thing that saves AM around here is the salt content of the ocean water?
I honestly can't picture that, risk of a volcanic eruption aside. Those peaks are simply too far away from the population these stations are trying to hit. Of the peaks mentioned, Mt. Baker or Mt. St. Hellens would be the most likely, but both are at least 30 miles from the nearest city. KRQT couldn't hit Castle Rock with a city grade signal from Johnston Ridge. The Bellingham big three *may* hit that city with city grade coverage, but Constitution is a much better location simply because it's closer to the population. A transmitter at Sunrise may hit Enumclaw with a city grade signal, but by the time you get to the major city of Seattle you're trying to target, I would think your signals would be fringe at best. Sure I've listened to signals that would be a similar distance, but those had a mainly water path. Going over land, especially with the terrain of the area, is likely not going to work.
Mt Constitution was an awesome place for TV/FM broadcasting until the Canadians removed the advertising expensing for US-based broadcasters. Imagine hitting both Vancouver and Victoria markets from there. The remaining advantage is that the Orcas Island site has regular power. Alternative mainland hills such as Lyman Hill and Cultus Mountain (where ham repeaters are located) all require fuel re-supply runs.
With all the backfilling of the FM band further south in the subsequent years, I doubt the Bellingham stations can now in that direction.
Getting back to the AM groundwave discussion - both KPUG and KGMI in Bellingham have lousy groundwave coverage southward. It's the glacial till of the Chuckanut Mountain Range (an extension of the Cascades) really chews up their signals.
Factoid: Around I-5 Exit 246 (Lake Samish) south of Bellingham one can find the second highest point along I-5 in Washington State. Obviously this is not as impressive as Oregon's Siskiyou Summit's 4310' which is the highest point along I-5., Exit 246 only reaches 530'. Let's designate it "Samish Pass" . The highest "I-5 summit" in Washington state is near in Lake Stickney in southern Everett at 545'. Let's designate that one "I can't pass - the freeway is jammed up".
With all the backfilling of the FM band further south in the subsequent years, I doubt the Bellingham stations can now in that direction.
Getting back to the AM groundwave discussion - both KPUG and KGMI in Bellingham have lousy groundwave coverage southward. It's the glacial till of the Chuckanut Mountain Range (an extension of the Cascades) really chews up their signals.
Factoid: Around I-5 Exit 246 (Lake Samish) south of Bellingham one can find the second highest point along I-5 in Washington State. Obviously this is not as impressive as Oregon's Siskiyou Summit's 4310' which is the highest point along I-5., Exit 246 only reaches 530'. Let's designate it "Samish Pass" . The highest "I-5 summit" in Washington state is near in Lake Stickney in southern Everett at 545'. Let's designate that one "I can't pass - the freeway is jammed up".
Mount Constitution is a fantastic site. Any high altitude site *could* be good, but without a reliable power source, there’s probably no point. Mount Constitution puts you at a perfect spot to hit all of the areas you need to service if you’re KISM, KAFE, or KWPZ. While the Canadian markets of Vancouver and Victoria may just be “bonus” coverage at this point, KISM and KWPZ both have a decent number of cross border listeners. And both come in great throughout parts of the market that aren’t serviced as well by Vancouver-centric stations.
You are correct. It’s a delicate balance of distance, convenience, height, and power. As I mentioned in a separate post, Kelly provided a very detailed explanation a while ago about why Cougar Mountain was so great. It’s a perfect place to broadcast, since you get the luxury of placing your transmitter close to the market, but also high above the market. It’s convenient, as power is easy to acquire, and an engineer can easily reach the top throughout the calendar year.
Tiger Mountain also is a great site to broadcast from. But accessibility can be problematic, and it’s located further away from the market. Also, there’s a power drop due to the HAAT. At my apartment (around 150 miles away from both sites), I can hear 97.3 or 95.7 just as clearly. For that reason, I’d probably prefer my equipment to be on the more accessible site (with better penetration into Seattle).
Fortunately, on the AM side, most of the major AM players in Seattle use Vashon Island, which is also a great location for AM. It’s close to the major population, and has the qualities required to be a good AM site.
Remember, for competitive stations coverage of the Nielsen radio market counties is critical. Coverage of counties outside the MSA (metro survey area) has little or no value for transactional sales.
The problem is that, like most coastal markets, many AMs have to be to the "other side of the ocean" to send a directional signal across the market and out to sea. Only the few stations that are only moderately directional or non-directional can be on the "wrong side of the market".
Using a different market, we can look at Miami which has about 23 AMs in the two-county metro. A couple of (former) Class IV stations don't cover even one county no matter where they are. Only 560, 1360, 610 are not confined enough that a coastal transmitter would work. But due to site costs and availability, all have had to move inland and 560 and 1360 have suffered loss of coverage. Everyone else is out in the Everglades shooting power back over the market.
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