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How good is your signal past the 60db contour

Height VS Power argument again. check out KZKR Jonesville,LA. just outside Natchez MS.i sold First Natchez this station years ago to go with their cluster.

Class A
AGL 244 meters
TPO 0.9kw

terrain flat as a pancake.i hear it booms into Natchez..
 
To the OP... DEFINITELY pay for the pattern study when you buy the antenna. I would also suggest you keep the bay count down and put some power out of your transmitter if this town is important to you... Class A, I would do no more than 3 Bay. It takes actual power to penetrate buildings in the fringe.
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Thanks Chris. Most engineers I have spoken to agree on this method.
 
oldiesstation said:
Height VS Power argument again. check out KZKR Jonesville,LA. just outside Natchez MS.i sold First Natchez this station years ago to go with their cluster.

Class A
AGL 244 meters
TPO 0.9kw

terrain flat as a pancake.i hear it booms into Natchez..
Click to expand...

My belief is that more height and lower power gets you better car reception. The opposite is true regarding building penetration.. Personal belief, opinion.
 
Height VS Power argument again. check out KZKR Jonesville,LA. just outside Natchez MS.i sold First Natchez this station years ago to go with their cluster.
Click to expand...

We are maxed out at 100 Meters. That is our only option. Nothing taller in the market.
 
chriscollins said:
oldiesstation said:
Height VS Power argument again. check out KZKR Jonesville,LA. just outside Natchez MS.i sold First Natchez this station years ago to go with their cluster.

Class A
AGL 244 meters
TPO 0.9kw

terrain flat as a pancake.i hear it booms into Natchez..
Click to expand...



My belief is that more height and lower power gets you better car reception. The opposite is true regarding building penetration.. Personal belief, opinion.
Click to expand...



Theoretically, that is true, but for a class A, unless the buildings in question are less than 5 miles from the antenna it makes virtually no difference. And at that distance you are penetrating everything anyway. If you need the height to overcome the terrain it's the way to go.
 
oldiesstation said:
Height VS Power argument again. check out KZKR Jonesville,LA. just outside Natchez MS.i sold First Natchez this station years ago to go with their cluster.

Class A
AGL 244 meters
TPO 0.9kw

terrain flat as a pancake.i hear it booms into Natchez..
Click to expand...
From my experience, parameters such as this produce a signal that carries forever but isn't 'strong' anywhere.
 
To answer the original question...both class A and class B stations in Indiana's flat lands have ratings as well as contest winners out beyond the 54dbu contour. I recall the local public swimming pool having a class A playing over the loudspeakers at the 45dbu contour. A bowling alley near here regularly plays a less than full powered class A at the 54dbu mark. Too bad protection doesn't extend to where the listening actually stops.
 
Many years ago, I was in Ukiah or possibly Willits CA. I think it was the local Radio Shack but the stereo receiver was on a San Francisco Rock station and the signal faded in and out. I'm pretty sure it was substantially less than 40dbu but apparently, they'd rather listen to this noisy major market station than anything local that might come in.
 
If people are willing to work at it, your station can be received beyond the 40 DBu contour. But the problem is, most people aren't willing to work at it, or don't know how.

I think that's the point of the original poster- how good is it beyond 60 dbu.

The answer is- it's less than optimal. At that point, while car reception is still really good, home reception, clock radios, offices, small portables (Walkman types) etc all don't come in very well in most places.

If you wanted to put a nice antenna on the roof you'd have tons of signal. But on what's at the desk of the average secretary or bedside table- not so much.

At -60, Joe Lunchbucket starts having a hard time receiving your station sometimes on some devices.
 
Several months ago I went near the top of a ~900-foot hill about 3/4 mile NW of my house. There, I recorded, using my Tecsun PL-606, 103.3 KVYB Santa Barbara, whose 105kW broadcasts from about 211 miles NW of that location. Any idea what is the contour I would be at there? According to Radio-Locator's coverage map for them, their 40 dBu contour doesn't even get halfway to my location, but I definitely consider it a usable signal, if just a little noisy.
 
pianoplayer88key said:
Several months ago I went near the top of a ~900-foot hill about 3/4 mile NW of my house. There, I recorded, using my Tecsun PL-606, 103.3 KVYB Santa Barbara, whose 105kW broadcasts from about 211 miles NW of that location. Any idea what is the contour I would be at there? According to Radio-Locator's coverage map for them, their 40 dBu contour doesn't even get halfway to my location, but I definitely consider it a usable signal, if just a little noisy.
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According to the FCC's propagation curves (through their online implementation) it's 16.5dBu (F(50,50)) at 300km. You were about 40km further away, but the curves aren't plotted that far.

That said:
- The propagation curves are a statistical thing. At 300km F(50,50) there will be at least 16.5dBu at at least 50% of locations at least 50% of the time. You may have hit a hot spot. (where it's maybe 40dbu at least 50% of the time) Or you may have been there during unusual tropospheric refraction. (where it was 40dBu at 50% of locations *all* the time for a few hours)
- In Kansas the "50% of location" thing is a lot less important. In California, terrain will have some rather dramatic effects on FM signals.
 
You'd really need a calibrated field-strength meter to say for sure. Keep in mind that the FCC's contour prediction methodology does NOT take into account the effects of coastal trop ducting on propagation, so just because their curves might predict that you're getting only 15 or 20 dBu at your location, you might actually be getting much more.
 
Interesting. I don't have a calibrated meter, but for those familiar with the Tecsun DSP radios, here's a photo of my PL-606 showing the "relative" signal display. That's not the actual dBu of received signal, though, it's based on the input to the DSP chip. Just because a distant station says "0" dBu doesn't mean it's actually 0 dBu, and just because a nearby station says "68" dBu (for example 2.7kW (550m HAAT) 89.5 KPBS at 7.04 km 171.53°(/351.53°), with a direct view of their tower (of many on San Miguel - I don't know which is which - maybe Fybush does?)) doesn't mean it's actually 68 dBu at my location. FCC curves say they should be 92.29 dBu.
 
I'd figured the original question had to do with how well your signal works past the FCC's predicted 60 dbu contour. At best the FCC's calculations are an estimate. You may actually have a decent signal way past that point.
 
pianoplayer88key said:
Interesting. I don't have a calibrated meter, but for those familiar with the Tecsun DSP radios, here's a photo of my PL-606 showing the "relative" signal display. That's not the actual dBu of received signal, though, it's based on the input to the DSP chip. Just because a distant station says "0" dBu doesn't mean it's actually 0 dBu, and just because a nearby station says "68" dBu (for example 2.7kW (550m HAAT) 89.5 KPBS atjavascript:void(0); 7.04 km 171.53°(/351.53°), with a direct view of their tower (of many on San Miguel - I don't know which is which - maybe Fybush does?)) doesn't mean it's actually 68 dBu at my location. FCC curves say they should be 92.29 dBu.
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The FCC predictions should be fairly accurate for the line-of-sight signal you're getting from KPBS. I'm not sure I'd depend on the Tecsun "dBu" readout for anything more than entertainment value, but if it's at least fairly linear, you could start by figuring that if a real-world 90 dBu or so from KPBS is translating to a "68 dBu" display on the Tecsun, the "21 dBu" display on the Tecsun for KVYB probably translates - very roughly - into 43 dBu or so of real-world signal, which certainly sounds plausible to me. The nature of the ducting propagation that carries KVYB to you is that it's going to be somewhat unstable and quite variable, so 43 dBu one minute could easily be 30 - or 50 - the next.
 
It is certainly possible that the Tecsun's built-in field strength is relatively accurate. You may have seen in one of the IEEE newsletters this past week that researchers have found it is possible to use 2.4 GHz radio waves to detect a person's rate of breathing, based largely on the diffraction of the radio signal as it passes through the person. This effect would probably amount to a few tenths of a dB.

A typical FM tuner IC would offer signal strength indication accurate to +/- 3 dBu (based on a glance at the offerings at DigiKey). However, the front end will begin to overload at around 70 dBu, making the signal strength indication less useful at close range.
 
Even if the chip in the Tecsun is giving a relatively accurate read at signal levels below 70 dBu, it still wouldn't necessarily match the FCC's predictions, which are based on a horizontally-polarized receive antenna at 9 meters above ground (73.314 has the complete rules for FCC-compliant FM signal measurements.) So "21 dBu" on the Tecsun, with the built-in whip essentially at ground level, still doesn't tell us much.
 
In the sprawling DC suburbs, the class B's designed 20-30 years ago push *at best* a 40-50db signal into some of the outlying commuter towns in northern VA. In most cases, radio listening at home is limited to local stations on average radios. However, given the extensive amount of commuters and traffic, car radio listenership allows a rated market like Fredericksburg, VA to have several stations with 40-ish db signals from DC to get very respectable ratings for being over 40 miles away!

Charlottesville, VA, right on the edge of the Blue Ridge, has some of the most impressive coverage areas outside of the 60 db contour. I pick up WWWV and WCYK (which are class B's on a mountain top) like locals over 60 miles away in several places. The class A's at the same sites are listenable in most places this far away on a semi-decent radio.

As you get more into the rolling hills of south central VA, the map generators can't really keep up with the numerous steep hills and valleys. Unless it's a tall tower, many class A's or C3's have terrible signals that don't go much farther than the 60 db contour. My old employer's competition down there had a 6kW/100m class A (modern tx and antenna, too!) signal that was not listenable in a car further than 15 miles away...our station was in a similar situation and maybe got 20 miles on a good radio.

As one of those lucky Charlottesville GM's said about local radio signals: "What the terrain gives, the terrain takes away." THAT is the truth around here.

Radio-X
 
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