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Seattle-Tacoma Area AM groundwave coverage - Crummy in spots.

Before we really knew anything about our local volcanoes, I'm sure they were all once posited as perfect FM/TV transmitter sites someday.
In fact, before Mt St Helens had its famous case of indigestion, Burlington Northern Railroad owned the summit. The theory was it would have made a great ski mountain until a survey showed the pumice and other volcanic materials made that untenable. Mt Hood (above Timberline Lodge no less) is the home to five FM transmitters - targeting Portland and the northern Willamette Valley.
 
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.
Very true David. I was hoping to show that there really isn’t much of a difference between FM from Tiger or Cougar if you’re listening somewhere on the edges of the market. But with that being said, there are some key differences smack dab where coverage matters most. Tiger Mountain experiences quite a bit of shadowing along I-405. Additionally, we’re all well aware that Tiger stations don’t perform as well in downtown Seattle once you drop too far over the hill.

With everything else being equal, I’d rather have my equipment on Cougar (if I were offered a choice). You get reliable electricity and ease of access thrown in. But as Kelly described (long ago), local residents were opposed to more stations moving in (and therefore Tiger still plays a major role in Seattle).

You’re absolutely correct about the AM issue as well, and I know that we’ve discussed this topic at length in the San Francisco forum (or perhaps the Canada forum, I can’t recall). Most of the power does get thrown to the west, which is problematic. 570, 710, 820, 950, and 1000 seem to be the only AMs that cover most of the market effectively. There are other stations that do okay, but are not nearly as strong in certain areas. Drive far enough east at night and only 710 and 1000 will sound clear.

One good thing about Seattle is that the market mainly runs north to south, which might mitigate this problem somewhat. Vancouver BC is a market that is expanding more to the east. AM stations in the Vancouver market are throwing power west and northwest, with massive dead spots nearby to the east. It seems more noticeable in this scenario compared to Seattle, but that’s a personal observation. If there were major population centers near the existing area of Snoqualmie, local AM would probably be pretty hit and miss.
 
In fact, before Mt St Helens had its famous case of indigestion, Burlington Northern Railroad owned the summit. The theory was it would have made a great ski mountain until a survey showed the pumice and other volcanic materials made that untenable. Mt Hood (above Timberline Lodge no less) is the home to five FM transmitters - targeting Portland and the northern Willamette Valley.
Isn't that tower right near Timberline Lodge? That's at least what I can tell from the elevation of that site. Because the lodge is there, I would imagine access is pretty easy to that site. The interesting thing about Portland in contrast to Seattle is that the Portland transmitters are located such that they cover Portland, Beaverton, Hillsburrow, Tigard, Oregon City, Gresham, Cammas, and Vancouver well but get out of the metro area in any direction except directly south and it's a crapshoot, even as close in as Newberg.
 
Isn't that tower right near Timberline Lodge? ...
Look to the northwest of Timberline Lodge about 150 - 250 meters. You will see two comm shelters there. Yes, Mt Hood is volcanically active. On a cold, clear winter's morning if you know where to look - from Portland you can see fumaroles emitting steam near the summit - e.g. Devils Kitchen.

Flip a coin which of the volcanos will blow first. In the 60s and early 70s everyone thought Mt Baker would be it. Now Rainier has become the focal point, mainly due to the population growth in the potential lahar areas... But this is a radio-centric discussion.

In the Sea-Tac metro area, South Mountain and Capitol Peak lately have become the growth points for radio sites.
 
Look to the northwest of Timberline Lodge about 150 - 250 meters. You will see two comm shelters there. Yes, Mt Hood is volcanically active. On a cold, clear winter's morning if you know where to look - from Portland you can see fumaroles emitting steam near the summit - e.g. Devils Kitchen.

Flip a coin which of the volcanos will blow first. In the 60s and early 70s everyone thought Mt Baker would be it. Now Rainier has become the focal point, mainly due to the population growth in the potential lahar areas... But this is a radio-centric discussion.

In the Sea-Tac metro area, South Mountain and Capitol Peak lately have become the growth points for radio sites.
South Mountain and Capitol Peak both seem to have their own unique challenges. A station like 97.7 seems to do extremely well from South Mountain, but trying to access it probably takes quite a bit of effort if something needs to be repaired. Winter accessibility would probably be the most challenging.

Gold Mountain stands out as a site that might solve some of those problems, but you’d run into the issue of being too close to the Canadian border.
 
Gold Mountain stands out as a site that might solve some of those problems, but you’d run into the issue of being too close to the Canadian border.
AirOne's KYFQ 91.7 broadcasts from Gold Mountain as a highly directional C1 , protecting a few northern Washington stations like KSVR in Mt Vernon (plus all the Canadians).
 
AirOne's KYFQ 91.7 broadcasts from Gold Mountain as a highly directional C1 , protecting a few northern Washington stations like KSVR in Mt Vernon (plus all the Canadians).
I usually use KCPQ or KTBW tv for benchmarking a coverage map. Plug any of those callsigns into a LR map generator and you’ll get a good indication of the coverage. Gold Mountain results in quite a bit of shadowing to to east side of the market, but overall, you still get the advantage of having your equipment close by (and with better LOS to the northern suburbs).
 
South Mountain and Capitol Peak both seem to have their own unique challenges. A station like 97.7 seems to do extremely well from South Mountain, but trying to access it probably takes quite a bit of effort if something needs to be repaired. Winter accessibility would probably be the most challenging.
The FCC today approved Bustos Media's KZTM proposed moved to a South Mountain tower slightly to the southwest. The Class C on 102.9 will run 80 kw ERP up there, putting a 60 dBu contour over most of Seattle and even up to Edmonds. That will be a monster signal.
 
The FCC today approved Bustos Media's KZTM proposed moved to a South Mountain tower slightly to the southwest. The Class C on 102.9 will run 80 kw ERP up there, putting a 60 dBu contour over most of Seattle and even up to Edmonds. That will be a monster signal.
What’s interesting to me is that even with the amount of land they have to cover before reaching the market, most of these South Mountain stations perform pretty well throughout the area. It’s not the ideal site to broadcast from, but it seems to be the best available option.

I’m not sure what the history or logic was for choosing South Mountain when the first site was constructed (whoever was responsible), but they must have been systematic.
 
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