Don't forget FM had an uphill battle as well.

[tomservo]

The story could be different in a troubled market like Birmingham or Pittsburgh or some other really hilly city.

So LA is not hilly?

The stations on Red Mtn. cover a lot better than most of the LA stations, as there is so much reflection, so many hills, canyons and mountains in LA.

Well, yes… but isn't most of the population in relatively flat land? Overall. Anyway, the analog coverage off Red Mountain is very good, but the HD coverage is the worst I've ever experienced. If it isn't the terrain, they have something massively wrong with the HD plants in that town.

 

[KeyTimes950]

The story could be different in a troubled market like Birmingham or Pittsburgh or some other really hilly city.

Good point on both counts about Pittsburgh, a troubled market and a really hilly city. Have noticed the following, however ...

Since WDUQ went to new ownership, the HD1 is all NPR/APM/BBC with the promise of some extended local news/talk later this year, the HD2 is a continuous jazz stream that seems broken up only by an hourly ID, and the HD3, BBC World Service, seems to be gone (perhaps deemed unnecessary because FM 90.5 carries it overnight on HD1).

KDKA-FM's HD2 is supposed to be WFAN New York but must cut it when that station carries play-by-play. Haven't found it for a couple days when I know no NY team is playing. On KD-FM's HD3 is its news-talk AM.

Given my location, I'm still doing contortions to bring in some signals.

 

[davideduardo]

So LA is not hilly?

Well, yes… but isn't most of the population in relatively flat land?

No.

If we talk only of the B's on Wilson, which are generally moderate to extremely grandfathered facilities, there is a lot of blockage.

The whole San Fernando Valley has mountain shadowing from the Santa Monica range. The valley is near 3 million people. Not all is shadowed, but there are so many canyons and ridges that where you don't have shadow you have mulltipath. Probably over a million have shadow or similar at home or while driving.

The Santa Clarita area requires boosters, and many have them. Otherwise, 300 k persons can't hear most LA stations most places. Lancaster Palmdale, another 300 k persons, most wilson signals horizon blocked, and the non-wilson B's like KROQ, KYSR, KLAX, etc. don't come in at all.

South Bay. Long Beach area is horizon blocked by signal hill. Some of west side horizon blocked by Baldwin Hills. Areas right under wilson like Sierra Madre, etc., may have blockage even with beam tilt.

Hills of Orange County. Lots of areas in rolling hills, valleys, big canyons, etc. Some flat areas have horizon blockage.

Interestingly, in many cases it is the higher income residences that are in the canyons, on the hillsides and surrounding areas. The flat LA basin is more than 70% ethnic, which is why several of the A's do well, despite no broad coverage.

 

[Tom Wells]

So LA is not hilly?

Well, yes… but isn't most of the population in relatively flat land?

No.

If we talk only of the B's on Wilson, which are generally moderate to extremely grandfathered facilities, there is a lot of blockage.

The whole San Fernando Valley has mountain shadowing from the Santa Monica range. The valley is near 3 million people. Not all is shadowed, but there are so many canyons and ridges that where you don't have shadow you have mulltipath. Probably over a million have shadow or similar at home or while driving.

The Santa Clarita area requires boosters, and many have them. Otherwise, 300 k persons can't hear most LA stations most places. Lancaster Palmdale, another 300 k persons, most wilson signals horizon blocked, and the non-wilson B's like KROQ, KYSR, KLAX, etc. don't come in at all.

South Bay. Long Beach area is horizon blocked by signal hill. Some of west side horizon blocked by Baldwin Hills. Areas right under wilson like Sierra Madre, etc., may have blockage even with beam tilt.

Hills of Orange County. Lots of areas in rolling hills, valleys, big canyons, etc. Some flat areas have horizon blockage.

Interestingly, in many cases it is the higher income residences that are in the canyons, on the hillsides and surrounding areas. The flat LA basin is more than 70% ethnic, which is why several of the A's do well, despite no broad coverage.

A very good summary of the sort of reasons FM had an uphill battle.
People were already accustomed to radio without such "flutters and spits" on mediumwave AM.
They hadn't yet bought lamp dimmers, and the car didn't have a CPU to hash out the noise floor.
The car radio had a REAL whip antenna and probably a tuned RF pre-amp.
AM on MW has its own characteristics that may be deemed "good" or "bad" .

Hilly areas have always been an argument for the use of AM mw.

The only place FM doesn't suffer as much from these effects in in flatlands without reflectors of some sort.

 

[tomservo]

Wow, I had no idea about all that in LA. I mean, I've been to the San Fernando Valley area a few times but never really got a chance to listen to the radio. Same in Long Beach. I'd forgotten about Signal Hill.

Would you say then that LA is NOT a good market for FM digital?

I thought the few trouble spots I encountered were minor, or due to the little Insignia's bad habit of easily being overloaded.

Edit to add: As for AM, I had trouble getting much of anything in the Malibu canyons on AM as well. In fact, with the amplifier off (it cuts out when it gets over about 80° outside or is very sunny) the only thing I could reliably seem to hear was one of the Sandy Eggo stations.

 

[davideduardo]

Hilly areas have always been an argument for the use of AM mw.

The only place FM doesn't suffer as much from these effects in in flatlands without reflectors of some sort.

Yet in the roughest terrain area I ever worked in, Quito, Ecuador, an FM station became #2 in the market in the late 60's and by the mid-70's AM stations started to go broke and by the 80's started to go silent. Quito is in a winding set of several valleys at about 9600 feet AMSL with hills and mountains of 1000 to 4000 feet surrounding much of it. Some of the suburbs are about 2000 feet lower, in another valley. My original solution was to do vertical only polarization, as horizontal produced excessive multipath.

Yet with all those problems, nobody wanted to listen to AM any more... it just sucks.

 

[Play Freebird]

Did anyone here have a chance to listen to Radio 24 (the most powerful FM station in the world) when it transmitted from the summit of Pizzo Groppera in northern Italy from 1979 to 1983?

This was a semi-legal FM "border blaster" that ran a 50 kW Collins transmitter (two 831H-2 in parallel) into a billboard array of 32 Kathrein circularly-polarized panels with a total power gain of around 160 (22 dB), yielding an ERP of 8 megawatts. The main lobe was directed at Zurich, Switzerland on the opposite side of the Alps -- an uphill battle indeed. Reportedly it could be heard quite well in stereo, even though the propagation was primarily by diffraction and scattering over the mountains. I would really like to find an aircheck demonstrating the audio quality (or lack thereof).

The Swiss government put a lot of pressure on Italy to shut the station down , with varying degrees of success. However, this led to a "people's rebellion" which opened the way for private broadcast ownership in Switzerland. The mastermind behind Radio 24 was Roger Schawinski, who was later profiled in the documentary "Jolly Roger". Guess I should try to find a copy of that video as well.

This page from an Austrian radio site has the technical details and some photos of the amazing antenna - who knows where that ended up? If you don't read German, Google Chrome or Language Tools will translate it fairly well:

http://members.aon.at/wabweb/radio/r24.htm

By the way, there is still a station called Radio 24 serving Zurich, but it now transmits from the local antenna farm with a modest 5 kW.

 

[Savage]

Not trying to be pedantic....but....

Equatorial regions have always been tough for AM radio, particularly the lower frequencies. There are frequent meteorological conditions which absorb mediumwave energy and drastically reduce coverage, making it unpredictably spotty. Plus the higher elevation causes problems at the transmission end. The less-dense airmass produces a lower "breakdown" threshold, exacerbating arc-overs in antenna systems on modulation peaks, so AM stations there have a hard time modulating as densely as systems we're used to. This further impairs coverage.

Given the historical problems AM has had in these regions FM must have indeed been a Godsend.

 

[Tom Wells]

Not trying to be pedantic....but....

Equatorial regions have always been tough for AM radio, particularly the lower frequencies. There are frequent meteorological conditions which absorb mediumwave energy and drastically reduce coverage, making it unpredictably spotty. Plus the higher elevation causes problems at the transmission end. The less-dense airmass produces a lower "breakdown" threshold, exacerbating arc-overs in antenna systems on modulation peaks, so AM stations there have a hard time modulating as densely as systems we're used to. This further impairs coverage.

Given the historical problems AM has had in these regions FM must have indeed been a Godsend.

And as the majority of my experience is in the high-wetness, high conductivity midwest, the milage does vary.

To some places the semi-optical behavior of 100 Mhz may be better suited than the "fog rising out of the ground" behavior of MW.

I really like being able to listen to WLS or WCBS, and a few rivers or mountains really shouldn't matter.

Tried to hear WYSL and/or WHO last night on the way to work. Not a chance... too much whooshling.
KDKA was just about intelligble under heavy hiss.

But WWL wasn't getting creamed too badly by WCBS.

I may do a youtube video about my drive to/from work and spitting sounds FM now makes since iboc.
It was bad enough before with just airplane multi-sptting, but the iboc now makes it really annoying as the
"incidents" that occur are a lot louder than when there were no buzzing sidebands.

For my use, it now means that AM ias definitely quieter than FM in most cases. And I'm already locked into straight mono FM.