AM stations- doubling up.

[Big 121]

AM stns. need a lot of land. Land that became more valuable than the station. KMJC(KECR) moved east to Lakeside; for more power/stronger metro signal. Its
old site on Magnolia was sold for the "SunBurst" development. KCBQ lost its Santee lease; Mayor Voepel called it an "eyesore", and now sites a big ugly
parking lot with stores the full length.THAT's an EYESORE!. KCBQ, years later tied in to KECR'S towers.Matching networks and some filters allow 2 differ-
ent transmitters to load into the common antennas. Other stations that have merged together for survival-
1240 hosts 1040's signal, fed into insulated wires running up the corners of the main tower. Bonilla couldn't afford a stand alone site.
1360 would like to move in Santee at the KSDO site and "share".
In L.A. , 1020 and 1150 are on the same antennas.
Santa Barbara-Residents hate of towers,political opposition, and stratospheric land prices forced THREE stations to share a single stick. 1290, 1340, and 1490
all use the same mast just west of the 101. The antenna was designed for 1290, so the "extra" height for the 1340 and 1490 stations allow them to run lower
power, and still give the required local signal.
It's ironic that 'listeners' never want to see antennas...NIMBY.
Big 121

 

[davideduardo]

It's ironic that 'listeners' never want to see antennas...NIMBY.

The issue of being an eyesore is not the main issue... it has always been the cost of land.

In Hawaii, where land has been very costly for a long time, there are several cases of three and four stations tuned to one tower. WCBS and WFAN have long been tuned to one tower in New York...

Another reason may be a shortage of the really desirable sites. In very mountanous Quito, Ecuador, I diplexed AMs back in the mid-60's to take advantage of good sites which were very few.

Of course, with FM we only have to look at the ESB, Hancock and Sears buildings and the Gannett tower in Miami-Dade as a couple of examples of common sites with many stations in single antena systems. In this case, it's the cost of big towers, allowable sites due to air routes, and site availabilty, too.

 

[Big 121]

On KCBQ-
Wrong on that one. After Bartell sold KCBQ, the subsequent buyers were just speculaters, wanting to cash out at a profit; the heck with the "public interest".
Later buyers cut costs, busted the union, and managed to unload it to Salem. Compounding the problem, the original patterns for the station were impossible
to achieve, even with computer modeling. Power had to be reduced to 1500w at night. Almost useless signal at that point.
When the leasor of the land beneath KCBQ sold it, the music stopped, and Salem had no chair to sit in.
KCBQ then used a wire antenna at KGB's site. The projected Muth Valley site was rejected. And then KECR agreed to let them diplex at their Morena Rd. site.
And that town's (Santee) Mayor, a pro-growth guy, only saw tax revenue-generating stores as beautification.
KCBQ was there before the Mayor was in kindergarten.
Big 121

 

[Garrett]

I believe the term you were looking for is "investors," in terms of speculating. A lot of companies did this.

With all due respect, I side with the Mayor on this one. Show me a radio station with 6 radio towers brings in more tax revenue than retail development.

 

[Big 121]

Garrett- Thought about your "eyesore" comment. You know, both you and the Mayor are right... I have always remembered KCBQ's site as it WAS, years
earlier...well maintained and green grass around the station buildings; before it became run-down. Darn memories got in the way of reality!
Big 121

 

[Garrett]

Garrett- Thought about your "eyesore" comment. You know, both you and the Mayor are right... I have always remembered KCBQ's site as it WAS, years
earlier...well maintained and green grass around the station buildings; before it became run-down. Darn memories got in the way of reality!
Big 121

Hey, I didn't say it was an eye sore (although it was surrouded by unkept brush and indeed rusting a bit). I was sorry to hear about the studio and the towers gonig away, because I thought it had potential. But given that it was all but abandoned property, I think commercial property makes sense.

 

[Big 121]

Two more SoCal stations tied together at the mast= High power KAZN 1300, and KMRB 1430.
Others with applications to "double up" are-
1600 KAHZ (ex KMNY/KWOW) Pomona to Yorba Linda, and sharing KLAA 830 facilities.
1320 KSDT Hemet, to Loma Linda, with KHPY (ex 1530) 1670, Moreno Valley.
Would be a lotta If's, but....
-IF KLSD ever pairs with KSDO, Jim Kelly's app (for1400 Lemon Grove), could lease the KGB tower, at a reduced power of say, 100 watts..
- and still protect our neighbor to the south.

Big 121

 

[hipman2]

May I ask why a radio station in Tecate moved their station from 1380 to 1390 when there's a 1390 in Long Beach just over 100 miles away? It's a mess on 1390 with two stations coming in at the same time.

 

[davideduardo]

May I ask why a radio station in Tecate moved their station from 1380 to 1390 when there's a 1390 in Long Beach just over 100 miles away? It's a mess on 1390 with two stations coming in at the same time.

The protected contour of Long Beach is not overlapped by the Tecate operation. In fact, the 5 mv/m of KLTX, a bit below the minimum for comfortable urban area listening, barely gets half way into Orange County, and the night signal is sent out over the Pacific mostly.

 

[pianoplayer88key]

KLTX's contour barely gets halfway into Orange County? Interesting. How is it then that I'm able to hear them at around 1pm in Ocean Beach (yes, it's mixing with XEKT) about 70-75 miles or so to the south? Is it possible that most of the general public uses radios that are less sensitive than, for example, my Tecsun PL-380 (which itself is lacking - I can't hear KERN 1180 here in El Cajon, even though in a rural area southeast of here I've heard 2 or 3 stations the same factor (2x) farther from radio-locator's fringe contour... but then it could be poor overload protection - after all KCBQ 1170's 50kW transmitter is 9 miles away and almost beamed at me)? Or, am I thinking of the wrong signal quality, compared to what you're thinking of? I can get by with a signal level of S-1 as in the example in this linked folder, but prefer something closer to S2. What do most people prefer, though, an S-9? (S7 to S9 at first sounds the same in that link, but S9 is stronger, as the signal splatters wider on the radio.)
So maybe what I think a 10mV/m signal (if I remember that's what you've mentioned for urban areas) translates to in real-world listening is inaccurate. In an urban area, would a seasoned ham have, at best, a 1% chance of correctly ID'ing a QRSS CW signal? Or, would 10mV/m be so strong that even with a 20kHz (10kHz audio frequency response) AM bandwidth, a lightning strike couldn't be heard over the unmodulated carrier even if it was within a few dozen meters? Or, what would it realistically translate to? (Also at approximately what level would a ham have less than a 50% chance of identifying a voice transmission in an urban environment?)

About that 1390... I too wonder why they moved from 1380 to 1390? I was looking around a little bit on radio-locator, and while I haven't factored in skywave, why couldn't they have had the same power on 1380? I don't think it'd be too short spaced to 1360 - after all, a radio I have with fairly poor selectivity (the aforementioned 1170 can be heard loudly almost to 1200, and at my grandparents' house 1/3 mile from KAZN and KMRB, those two stations are pretty much heard solidly from around 1220 to about 1520 or so) does just fine at separating XESDD 1030 and KURS 1040 here, and in other places in San Diego (unless I'm within sight of the base of KURS/KSON's tower, maybe). Also if they were on 1380, that app on 1400 could probably squeeze in.

Speaking of land being at a premium... isn't there a way a station can take up very little real estate, and still have an efficient transmission? For example, KFBK in Sacramento, CA, uses two stacked 180° elements insulated at the center for each tower (also known as a Franklin antenna), and doesn't even need a ground system. Also, many other stations have self-supporting towers, eliminating the need for guy wires and the real estate they take up. And, in case something goes catastrophically wrong, KFI's previous tower from what I heard behaved as designed when it failed - took up only a relatively small footprint on the ground. Is there a way to combine those 3 - self-supporting Franklins designed to collapse on itself if it falls? While I never expect to win a construction permit for a station, I theoretically think I could maybe fit a tower on the 1/2-acre lot here, if it was designed that way.

Regarding stations paired together... if two FM or TV stations used directional antennas aimed opposite directions (intended to serve different markets), how close in frequency could they be and share the same tower? For example, if there was a site up at a high elevation in the Tehachapi mountains, and one station aimed north to serve the southern San Joaquin Valley (Bakersfield, for example), and the other aimed south to serve Los Angeles, San Bernardino, San Diego (I think this would be possible - I can hear an FM station from Santa Barbara from here east of San Diego) and surrounding areas, could they be on the 2nd adjacent, or maybe even 1st adjacent or possibly co-channel if the transmitter site is some distance away from civilization (so that almost no one would be likely to live in an area where the two stations would interfere with each other)?


And.... what's the most AM stations anyone knows of sharing a single stick, or most directional signals sharing the same set of towers?

 

[Tom Wells]

KLTX's contour barely gets halfway into Orange County? Interesting. How is it then that I'm able to hear them at around 1pm in Ocean Beach (yes, it's mixing with XEKT) about 70-75 miles or so to the south? Is it possible that most of the general public uses radios that are less sensitive

Sensitivitiy of radios varies a great deal, and so does the noise encountered in different areas.

The difference in sensitivity rally became a issue once manufacturers stopped putting tuned RF amps in AM sections.
Better radios made up the difference in "better" IF sections but still are poor in rejecting overload froom strong signals nearby, as you've noted.
For a real eye (or ear opener) compare sometime an old 5-tube superhet to a modern step-tuned "boom box" on AM.

AM works much better than the average person has had any experience with, considering the deafness factor combined with the noise factor.
Of course, at one time, our Amercian automobiles had their mettle ( and technology ) proven in NASCAR races.
Now people accept minivans that can barley get out of their own way, much less stand up to the torture of racing.
At one time such poorly performing radios wouldn't have even been offered for sale.
Now just as with minivans, it has become the sorry standard we "accept".
Well, some of us.

 

[w9wi]

So maybe what I think a 10mV/m signal (if I remember that's what you've mentioned for urban areas) translates to in real-world listening is inaccurate. In an urban area, would a seasoned ham have, at best, a 1% chance of correctly ID'ing a QRSS CW signal?

(FWIW, QRSS doesn't use a human operator. The idea is to use EXTREMELY slow Morse speeds -- 30 seconds per dit -- to allow software to integrate out noise & interference. I suppose you *could* copy QRSS by ear, but no ham has that much patience!)

I theoretically think I could maybe fit a tower on the 1/2-acre lot here, if it was designed that way.

I think you'd run into zoning issues.

Regarding stations paired together... if two FM or TV stations used directional antennas aimed opposite directions (intended to serve different markets), how close in frequency could they be and share the same tower?

800KHz separation is common. I'm not an antenna expert but I don't think the use of directional antennas or the directivity of said antennas enters into the equation. A wavelength is so short that it's practical to mount antennas in a way that they don't interact.

And.... what's the most AM stations anyone knows of sharing a single stick, or most directional signals sharing the same set of towers?

I know of a four-station array near St. Cloud, Minnesota.

_________________________________________________

David, isn't Hawaii a bit of a special case for diplexing? In that there are few, if any, directional stations in the Aloha State?

 

[pianoplayer88key]

So maybe what I think a 10mV/m signal (if I remember that's what you've mentioned for urban areas) translates to in real-world listening is inaccurate. In an urban area, would a seasoned ham have, at best, a 1% chance of correctly ID'ing a QRSS CW signal?

(FWIW, QRSS doesn't use a human operator. The idea is to use EXTREMELY slow Morse speeds -- 30 seconds per dit -- to allow software to integrate out noise & interference. I suppose you *could* copy QRSS by ear, but no ham has that much patience!)

Hehehe... lol... yeah... I will say I guess I was being a bit extreme with the opposite scenario of what 10mV/m could be... on one hand either so faint that no one except God Himself could dig it out, or so strong that you could fill a ~500-1000 seat auditorium with a speaker hooked up to a simple crystal set without an antenna and that's AFTER the signal makes it through the Faraday cage that some buildings seem to be.

I theoretically think I could maybe fit a tower on the 1/2-acre lot here, if it was designed that way.

I think you'd run into zoning issues.

Yes I probably would.

Regarding stations paired together... if two FM or TV stations used directional antennas aimed opposite directions (intended to serve different markets), how close in frequency could they be and share the same tower?

800KHz separation is common. I'm not an antenna expert but I don't think the use of directional antennas or the directivity of said antennas enters into the equation. A wavelength is so short that it's practical to mount antennas in a way that they don't interact.

Yeah... I was kinda thinking that if one station wanted to serve Bakersfield and the other wanted to serve L.A., they could put a site in the mountain range between the two cities, in an area where no one lives there within a several mile radius. I guess the technology doesn't exist, though, for them to use directional enough patterns (one beaming north, the other beaming south) to be co-channel. (I guess I'd be correct in assuming co-channel DA diplexing on AM would be impossible, even if the stations were intended to serve completely different areas, and the transmitter site was 50-100+ miles from civilization... like an example I just thought of - a directional array somewhere at or below 600 kHz about 350 to 500 miles off the coast of northern California, one 50kW signal beamed toward Los Angeles, another aimed at San Francisco, and a third at Portland or Seattle. (If 500 watts on 1290 makes it 195 miles, including about 15 or so miles inland, I'm not sure why 50kW below 600kHz couldn't go 350 miles with an comfortable urban signal.))

And.... what's the most AM stations anyone knows of sharing a single stick, or most directional signals sharing the same set of towers?

I know of a four-station array near St. Cloud, Minnesota.

Do you know which stations those are?

_________________________________________________

David, isn't Hawaii a bit of a special case for diplexing? In that there are few, if any, directional stations in the Aloha State?

 

[pianoplayer88key]

KLTX's contour barely gets halfway into Orange County? Interesting. How is it then that I'm able to hear them at around 1pm in Ocean Beach (yes, it's mixing with XEKT) about 70-75 miles or so to the south? Is it possible that most of the general public uses radios that are less sensitive

Sensitivitiy of radios varies a great deal, and so does the noise encountered in different areas.

The difference in sensitivity rally became a issue once manufacturers stopped putting tuned RF amps in AM sections.
Better radios made up the difference in "better" IF sections but still are poor in rejecting overload froom strong signals nearby, as you've noted.
For a real eye (or ear opener) compare sometime an old 5-tube superhet to a modern step-tuned "boom box" on AM.

AM works much better than the average person has had any experience with, considering the deafness factor combined with the noise factor.
Of course, at one time, our Amercian automobiles had their mettle ( and technology ) proven in NASCAR races.
Now people accept minivans that can barley get out of their own way, much less stand up to the torture of racing.
At one time such poorly performing radios wouldn't have even been offered for sale.
Now just as with minivans, it has become the sorry standard we "accept".
Well, some of us.

I've noticed that, somewhat. I'm not old enough to remember some older radios - for example I was about 12 or 13 or so when I got my first Panasonic RQ-SW10 which I believe was a new model at the time. It seems that most of today's pocket radios are sorely inadequate for what I want to do. I tried to replace the aforementioned Panasonic with a Tecsun PL-380, but unfortunately I still can't hear the stations I wanted, or if I can, they're practically buried below the noise. It doesn't help that a signal I may want to hear is often upwards of 30+dB below that Pana's noise floor, and a non-IBOC blowtorch 10kHz away may be heard almost across the entire band.
Is there anything like an "ultralight" pocket radio with multiple bandwidths, signal strength indicator (like a few DSP models), a C-Quam decoder, several ganged tuned RF amps, synchronous detection, passband tuning, etc? Or does it not exist, at least at an affordable price for someone who doesn't have a lot of money to throw around?
As for sensitivity, I am thinking I don't like radios where there are a lot of blank spots on the dial. I would rather have co-channel interference on the frequency of a 1-A clear south of 33-34° latitude, at solar noon on the summer solstice, with at lest two stations being strong enough to be able to her their audio. Regarding selectivity, I like to be able to hear weak stations at the noise floor 10kHz away from a mega-strong local, and reject overload well. IMO a radio shouldnlt begin to show signs of overload until you're within a couple dB or so of the FCC's maximum safe exposure guidelines. Unfortunately most radios the size and price I've been looking at can't do that.

 

[Tom Wells]

You might want to experiment with creating a very small tuned loop with a ferrite stick.
Or be bold and make a big air loop. First, this "outer loop" must be tuned with a variable cap, then there must be a loosely coupled inner loop of just few turns. If it's a stick, it would be 3-4 turns at one end of the stick.

This is what you will couple into the radio, by winding 3-4 turns around the radio, or its internal loopstick.
Ideally, the radio would then be in a shielded box to make sure the only pickup is from the coupling, with none from the air directly.
You'll note a HUGE increase in sensitivity as you tune the loop if it's working correctly.
Good luck.
It can be done.... it's just a pain, and wouldn't it be a heck of lot easier if radios were still made this way?

 

[davideduardo]

KLTX's contour barely gets halfway into Orange County? Interesting. How is it then that I'm able to hear them at around 1pm in Ocean Beach (yes, it's mixing with XEKT) about 70-75 miles or so to the south?

The issue is hearing vs listening. Nobody listens to a frequecy where two weak signals are hashing eash other. They might hear them is they spent the time to tune between the listenable channels, but most people use AM car radios with seek buttons which just skip this kind of thing.

The average listener, as proven by studying literally millions of at home and at work listening diaries will not tune into a weaker signal or one that is not inteference free. In general, metro area AMs that don't have a signal around 10 mV/m in noisy mixed use area will just not get any listening... on average, 95%of listening is "Inside the Ten" so whether you can DX a signal is irrelevant... nobody will listen to it.

Of course, this bring up the matter of AM listening in general... outside the top 30 or 25 markets, AM listening is somewhere around a 10 share, while FM has a 90 share. And in people under the age of 55, the figure falls sometimes into the lower single digit share range. FOr example, Indianapolis, IN has averaged less than a 7 share for all AMs for several years and the listening in advertiser-desired demos is less than 5%.

 

[pianoplayer88key]

I guess I must be in the minority... I'm under 30 (barely - will be 30 next year), and rarely listen to FM. For one thing, most of the programming I like is on AM. Also, I happen to like listening to stations that have the potential of having a greater than 100 or 150 mile coverage radius, something that FM seems to rarely achieve - I can regularly receive a station from Santa Barbara, CA, about 212 miles away from here, but otherwise some L.A. FMs (Mt Wilson?) seem to be the limit. For example, I would probably enjoy it if, while I was driving cross country all day (starting one place around sunrise and reaching my destination, or at least having covered some significant ground, at around the summer solstice in the northern states of the lower 48.... while tuned to the same station the entire way, and not paying for a subscription to XM/Sirius or similar. I think in some areas with good ground conductivity, 50kW near the lower end of the dial could achieve that. For example, I think I may be able to hear KALL 700 North Salt Lake City, UT, from here (626 miles) in the daytime without a Select-A-Tenna if I didn't have much in the way of local stations on the air desensitizing / bleeding over my PL-380.

So a 10mV/m signal is strong enough so a lightning strike would have to be within about 100 feet to be heard at all, when the station's broadcasting an unmodulated carrier? Or, is it just strong enough so that an AM signal seems to have a similar signal to noise ratio to something like a CD or 24-bit digital audio recording? For example... while this is not close to 10mV/m, it's received on the PL-380 aided by the Select-A-Tenna, and it's probably not as noisy here as inside a factory in downtown L.A. - would people still expect better quality than this recording of KNX 1070 in my back yard?


I do have a Select-A-Tenna, but then I can't exactly carry the radio in my pocket / clipped to my belt (prefer in my pocket - might get jostled off if it's in my belt) while I'm walking/jogging or biking around town... and I still want to find something with which I can hear those stations that are absolutely hopelessly lost (20+dB below its noise floor, and 10kHz away from strong locals that bleed 300+kHz away as loud as on the main channel) on my other radio (which was actually a bit too BIG for my pocket anyway - for example I don't need a cassette player, and that Panasonic has one built in). Maybe asking to listen to KERN 1180 within 10 miles of KCBQ 1170's transmitter site (and NOT in one of their nulls) or KKDD 1290 within 1/2 mile of KAZN 1300's site (or other stations that would be similarly difficult) on a pocket radio is asking too much?

 

[davideduardo]

So a 10mV/m signal is strong enough so a lightning strike would have to be within about 100 feet to be heard at all, when the station's broadcasting an unmodulated carrier? Or, is it just strong enough so that an AM signal seems to have a similar signal to noise ratio to something like a CD or 24-bit digital audio recording? For example... while this is not close to 10mV/m, it's received on the PL-380 aided by the Select-A-Tenna, and it's probably not as noisy here as inside a factory in downtown L.A. -

What we know is that 95% of AQH in home and at work listening quarter hours happens inside the 10 mV/m in larger metros (pretty much any of the top 50 markets) and very little happens outside this. So you can make your own conclusions on why anything less does not attract listening.

 

[sdwulfdawg]

I believe the term you were looking for is "investors," in terms of speculating. A lot of companies did this.

With all due respect, I side with the Mayor on this one. Show me a radio station with 6 radio towers brings in more tax revenue than retail development.

Garrett, what galaxy are you in most of the time? I've seen your inane posts in the past, rolled my eyes, and ignored them.

These are SPECULATORS (Clear Channel, Salem, Emmis) who are leveraged investment companies who don't give a crap about listeners...just the people who put money in their Ponzi schemes. INVESTORS pool their money for a common good.

You need to grow up and not spout out euphemisms just because they sound "positive."

 

[SDRadio]

Garrett, what galaxy are you in most of the time? I've seen your inane posts in the past, rolled my eyes, and ignored them.

Post of the year, decade, century, and millennium.