Places in contiguous 48 US states with _absolutely_ *NO* detectable AM (MW) signals?

[pianoplayer88key]

A similar thread on FM, and some of the replies therein, inspired this post.

So is there any place in the 48 US states where this is true? And no cheating by going deep inside Carlsbad Caverns with a plasma TV, crystal set and no antenna at solar maximum during an 1859-level solar storm.

Here's the criteria :

• Use the most sensitive radio circuit in existence (without taking into account gain from an external antenna). For example a high-end SDR that overloads with NO antenna would score higher than a pocket dollar-store Coby that can't detect anything in the same spot at the same time with one of Bruce Carter's large loops.
• Using the highest-gain type of antenna in existence. I don't know if this would be a capacitor-tuned multi-wavelength multi-element phased Beverage array, but if you hooked it up to Rich Fry's PL-310, KFI's 2nd harmonic should hopefully read 98 dBu (and be overloading/blocking so severely it sounds like an unmodulated carrier) about 3x as far (and in the same direction) as the Coachella Valley.
• It should be extreme solar minimum, with an MUF so low WWV can't be heard at all outside Colorado (not even 2.5 MHz)
• Should be December/January, preferably the winter solstice.
• While I'd prefer this be midnight, I'll allow for midday ± 4 hours at the receiving location.
• There should be no solar disturbances / aurora that would affect the ionosphere, other than whatever's normal for time of day.
• The receiving setup MUST be in the clear - not in an environment which attenuates signals.
• There should be *NO* manmade noise detectable
• The nearest lightning noise source should be at least 8k miles / 13k km away
• absolutely NOTHING can be detectable on the radio. Not even so much as the slightest trace of a carrier, even if it's too weak to tell what type it is (like QRSS CW, PSK31, etc), nevermind ID it.

So, is there any place in the lower 48 with NO AM / mediumwave band signals?

A quick note - I know Bruce Carter has heard IBOC sidebands from Chicago in New Mexico at midday, using a setup many decades (if not centuries) of dB less sensitive than what I have in mind, with an ambient noise level several decades of dB higher.

Or, if such a place doesn't exist, what are some locations that come the closest?

 

[crainbebo]

Pretty much absolutely nothing on the dial N of Las Vegas on US-95. Barely can detect KDWN, if that, 100 mi N of Vegas (several DXers have gone through there). At night the band opens up like any ordinary skywave band.

Also, middle of the ocean between EU and North America, likely. Right in the middle, there is probably zero daytime reception. KR4BD barely copied WTAR-850 in VA as well as the Bermuda stations, 500 miles ENE of Bermuda. VA is 1000 miles from that spot. Another couple hundred and WTAR is probably gone, forever, even with a beverage.

-crainbebo

 

[rfry]

... So is there any place in the 48 US states where this is true? And no cheating by going deep inside Carlsbad Caverns with a plasma TV, crystal set and no antenna at solar maximum during an 1859-level solar storm. etc etc

The complete post including the clip above asks for responses to a set of conditions that are impractical/impossible to evaluate or achieve.

Even if someone spent the time/money to buy and optimize the receive hardware outlined in PP88K's post, that would not apply to probably 99.999+% of the rest of us in the real world.

 

[Buckeyes2001]

On the winter solstice, I would suspect the best chance of finding a spot with no AM reception even with the most sensitive receiver to be somewhere near the tropic of cancer and in the ocean furthest away from any land points at solar noon or even +/- 4 hours from solar noon. Within the contiguous 48 maybe someplace around Eureka, NV

The mention of MUF's got me thinking - what's the lowest MUF that's ever been detected? We hear about high MUFs during e-skip but how low has it even gotten?

 

[Schroedingers Cat]

As R. Fry and Scott Fybush have noted, PP88Keys conditions are difficult to achieve at best.

Practically speaking, there are areas with few if any signals across the AM band in the daytime that are listenable with normal radios. All you really had to have to get something is a 25 foot vertical wire (you can use twin lead from the TV antenna and twist the leads together) fed into a one transistor preamp. I posted a list of stations I got that way in West Central Michigan on another unsearchable thread. You could only get one AM well without it. At the time WMAQ was empirically the second strongest station in that region. It quickly became the strongest along the shore of Lake Michigan, rising to the 1 mv/m range. Today, WTMJ would be the strongest in places along Lake Michigan, along with WSCR in others.

 

[rbrucecarter5]

I can cheat a bit - going on I-10 under Mobile Bay both bands are blank in the middle of the tunnel. I would guess you would have to go to the interior of Alaska to find a place - again cheating but it is the US. I'll ask Lisa Kelly what she gets along the Dalton. Of course those trucks generate a lot of interference and most of them listen exclusively to satellite. There are places along highway 93 in Banff and Jasper National Parks in Canada where the dial is almost blank. We stayed at a motel - somewhere - along that road one night. I had a Radio Shack 12-675 with me at the time - it was about the most advanced radio on the market in the 60's. There were two very faint AM signals. But that was Canada and cheating.

If there is anywhere in the US, it would have to be in the Montana, Idaho, Wyoming, Utah area. Those are the only plausible places, although extreme Northern Maine, NH, and VT might be a possibility. But proximity to Canada always introduces the possibilty of reception over the border. Because of climate, a lot of Canada's population is along its southern border.

I would also propose the Grand Canyon as a possibility. It is out in the open, and the depth would be a great attenuator of radio signals. Anybody carry a radio down on the donkey?

KCRS ruins the Big Bend area for lack of radio. It is a bit of a regional powerhouse. There is also a little 860 in Ft. Stockton that does a great job of getting out for the power it has.

 

[ftballfan]

Some inland parts of Michigan may qualify due to the bad conductivity there

 

[Steve Green NEPA]

How about northern Maine?

Many Canadian-border AM stations have gone to FM. Maine is one of those
states with no 50,000 watt AMer, as well.

Radio's Jean Shepherd (who had a ham license himself) described that stretch
around Metro Lake Mooselookmeguntic as something like 'the darkest, blackest
nighttime wilderness on the face of the planet'.
It can't be too much more like Las Vegas during the day.

 

[crainbebo]

I suppose with my 3-foot box loop that KFST 860 Fort Stockton would come in like a local at Big Bend - prob even a few others other than KCRS. My loop can do some amazing things.

Also I've heard Tok AK is an AM-dead zone, day and sometimes even night, besides from maybe 1 or 2 weak ones.

-crainbebo

 

[fybush]

Reiterating my question to pianoplayer about just how much time he spends concocting these insane scenarios of his...

And in answer to Bruce, I don't think the Grand Canyon would be as much of a dead zone as he surmises. The rim of the canyon gets 0.5 mV/m from several AM signals (and would do even better if Flagstaff's KVNA 600 were on its licensed facility instead of a long-term longwire STA). With a decent antenna, I'd think KDWN, Flagstaff's KAFF 930, KAZM 780 from Sedona and possibly KTNN would all be minimally usable down in the canyon.

Northern Maine? There was never huge AM from Canada there anyway - most of the signals rimming the Maine wilderness were fairly small locals and regionals. Bangor's 620 and Rumford's 780 go pretty far north, and 600 from Caribou covers most of Aroostook County. The area that would have the least AM these days would be northwestern Maine, out around Jackman. Until CHRC 800 from Quebec City went off the air last year, its signal was weak but audible there. Now? Maybe a very weak 780 from Rumford.

 

[Schroedingers Cat]

Some inland parts of Michigan may qualify due to the bad conductivity there

The strange thing is that the AM stations inland in Lower Michigan where the conductivity is low have been disappearing. WSNQ 900 Gaylord, WBMB 1060 West Branch, and WHGR 1290 Houghton Lake are three examples. Driving between West Branch and Gaylord, WSGW 790 Saginaw is often the only AM station that stops the scan. South of West Branch, the Detroit powerhouses, and the more powerful Flint and Tri Cities stations only get so far. When you get to Grayling, WGRY comes in for a while, but you have to get up further before the Northern Michigan stations come in well.

 

[rbrucecarter5]

I suppose with my 3-foot box loop that KFST 860 Fort Stockton would come in like a local at Big Bend - prob even a few others other than KCRS. My loop can do some amazing things.

Also I've heard Tok AK is an AM-dead zone, day and sometimes even night, besides from maybe 1 or 2 weak ones.

-crainbebo

I didn't have any problem with KFST all over Big Bend on a car radio - it was amazing to me what that little station did. It must have amazing ground system. That or they cheat - who would know or care? KCRS was pretty strong, particularly north of the park. Plus some Mexican stations. But I have no idea where they came from.

 

[rbrucecarter5]

Also I've heard Tok AK is an AM-dead zone, day and sometimes even night, besides from maybe 1 or 2 weak ones.

-crainbebo

No answer from Lisa - who is pretty talkative when she isn't trucking. So today must be another Prudhoe run.

 

[BMR]

P
Also, middle of the ocean between EU and North America, likely. Right in the middle, there is probably zero daytime reception. KR4BD barely copied WTAR-850 in VA as well as the Bermuda stations, 500 miles ENE of Bermuda. VA is 1000 miles from that spot.

-crainbebo

I know the OP specified MW, but if you count LW, you ought to be able to receive some signal from the BBC on 198 mid atlantic, and possibly other stations from Europe too.

 

[boombox4]

In all my years of listening to the AM band, the only place I remember hearing no AM stations during the day was parts of South Central British Columbia, in the mountains on Highway 3, near Greenwood in the boundary country. Of course, this was in the late 1970's, and at the time my main AM radio was a decent multiband transistor, but not as good as a TRF or Superadio. So if I'd have had better equipment, it may not have been a dead spot. The only AM signals one could hear during the day were the AM CBC translators (most of which are probably gone now).

 

[rbrucecarter5]

from Lisa Kelly: "yes. the entire Haul Road has no radio."

So there it is - I double checked the maps on Radio-Info, and the Dalton Highway (11) from Stephens Village on to Prudhoe is likely AM blank. Prudhoe has 4 FM's but they are low power translators.

 

[MarioMania]

Have anyone tried the AM Band in the Daytime at the Valley of Fire Nevada State Park?