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LRN.FM - The Liberty Radio Network => Free Radio Forum => Topic started by: sillyperson on June 11, 2010, 11:56:01 PM
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Okay.... let's say I have a 2 story property in a semi-metropolitan area (like Manchester and/or Concord).
Let's say I throw decent equipment at this puppy. You say Rangemaster is La Bomba, fine, I get a Rangemaster. You say I need a low-pass filter and 2 flux capacitors, fine, I go get exactly that.
Furthermore, let's say the property is on a bit of a hill -- not the highest point in town, but sure as hell not at the bottom of a valley, either.
The real question I have is, assuming I have ZERO interest in Feds having an excuse to raid my ass, and assuming therefore that I make a clear, good-faith effort to remain strictly within the law Part-15-wise,
all other things being equal... what kind of range can I expect?
Are we talking 2 blocks, or are we talking ~2 miles?
This is not idle chatter. It's a straight question I've never got a straight answer on. I don't mind setting up but only if the investment will be worthwhile.
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If you do it correct AND legal:
I say usable for a mile on AM
I say usable for 1000 feet on FM
This is based on experience with FM and research on AM.
The beauty of the Rangemaster is that it has proven performance and the FCC says it's good.
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Thank you, I appreciate that.
~1 mile radius is pretty lame, I have to say.
Looking at Google maps to get an idea of the area I'd be able to hit... shit, ain't worth it :(
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If you don't like the FCC rules, you should work to change them.
Or, you could just move your illegal operation if you get a letter telling you to stop. :lol:
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You only get 1 hill to die on, you know. Breaking Federal laws is not in my plan.
I was thinking today about the logistics of setting up enough legal transmitters to get decent coverage of well-populated zones. We could possibly do it in Concord, because the downtown is so small. Manchester, we could hit some well-populated areas. We could then put up a few signs for "Manchester Free Radio 1776 AM" and boom, LRN gets a bunch of NH listeners.
A lot would depend on how many Porcs can be found that have their shit together enough to (a) own a building to put the antenna on, (b) have the cash to buy the equipment, and (c) follow through on plan.
For now I have lower-hanging fruit just getting my constitutional/libertarian/anarchist-themed political talk show in more NH towns. I'd love someone to organize a Part-15 patchwork effort -- I'd happily put up an antenna in Concord & Manch -- but I can't spearhead this, not right now.
KDus, you seem gung-ho, when are you gonna come up here and show us how it's done?
EDIT--- one more thought...
What does it take to get the smallest-available broadcast license?
I grok there's a lot of paperwork and it's annoying and not cheap. But, exactly how "not cheap"?
I'm thinking of a license to pump out just a couple of watts, noncommercial. Can such license be had for a few thousand bucks? Is there a "low-end" license?
Sure, there's amateur, but virtually nobody has a receiver. Gotta be AM or FM.
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Holy crap:
http://www.fcc.gov/mb/audio/howtoapply.html
NOTICE: THE FCC IS NOT ACCEPTING APPLICATIONS FOR NEW AM BROADCAST STATIONS AT THE PRESENT TIME
... what BS!
NOTICE: THE FCC IS NOT ACCEPTING APPLICATIONS FOR NEW Low Power FM (LPFM) BROADCAST STATIONS AT THE PRESENT TIME!
.... jeeesus
So what about "FM Noncommercial Educational Stations" ?
http://www.fcc.gov/mb/audio/bickel/amfmrule.html#FMED
http://edocket.access.gpo.gov/cfr_2009/octqtr/pdf/47cfr73.511.pdf
(a) No new noncommercial educational station will be authorized with less power than minimum power requirements for commercial Class A facilities. (See § 73.211.)
And according to this (http://www.ntia.doc.gov/ptfp/application/equipcost_Radio.html) doc, that means about a 350' tower.
So, short answer is, "noncommercial" is out, it would cost nearly $100K just for all the equipment you need to be eligible to realistically apply for the frickin license. :roll:
SO... Low Power FM is the only realistic option here. About 3.5 mi radius, according to the FCC, but I bet 5 mi can be done within spec. That would be just fine. I guess I need to look into it more. The page talks about required "construction permits", I wonder if it's even legal to just slap an antenna on top of your 2-story house and be done with it.
http://www.fcc.gov/mb/audio/lpfm/index.html
It can't be that un-doable... I see freakin' Churches with LPFM licenses in Concord:
http://www.fcc.gov/fcc-bin/fmq?state=NH&serv=FL&vac=&list=2
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For the amount they charge for the rangemaster, it better have a low pass filter in it. Are you gonna let the FCC in to "inspect" your operation?
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My buddy in Sun Valley was so disappointed with his part15 AM, getting about 1/4 mile usable, that he put up an FM on a 40' pole.
I put a small amp on his rig, so it is probably 500mW of effective power. We're actually considering turning it down. It is usable for a mile and spotty after that, but usable in some places up to 2 miles.
Remember, he's on top of a 40 foot pole.
Yes, I was going to say a non-com license is about 100k
The churches got in when it was a little easier, but they did spend lots of money.
There is an AM for sale in L.A. for about 80k
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I put a small amp on his rig, so it is probably 500mW of effective power.
Is that "legal" (just asking -- I have no sense for the numbers involved)
We're actually considering turning it down. It is usable for a mile and spotty after that, but usable in some places up to 2 miles.
Remember, he's on top of a 40 foot pole.
Sweet ... 40' above ground level, or 40' on top of a building?
Like I said earlier, I have a 2-story, which means an antenna would start at higher than 40' for me.
1 mile is the minimum useful range I can imagine doing a project like this for.
With 1 mile, I could cover Concord High School and much of downtown.
2 miles would let me cover about 1/3 of Manchester -- big win.
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40' off the ground.
No, the legal power is defined as a certain amount of radio signal at a specific distance, and you can use up to 100mW to get to that level.
I think you can expect a mile from a height like that; even legal. However, while you'll have good line of sight, the "shadows" will be significant. You'll have dead spots behind buildings, trucks, trees, hills. We call it picket fencing.
Commercial stations run, typically, 5kW, and that is why the signal doesn't drop out while you drive around.
Since you seems serious, send me the GPS, or address, and height above ground where you want to radiate, and I'll send you a computer model of your coverage. Here's mine.
http://www.facebook.com/photo.php?pid=30093742&id=1254494962
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you can use up to 100mW to get to that level.
Interesting... I would be willing to pump say 98mW and assume I'm playing it safe. Then if it came to trial before a judge, I can show I've clearly been acting without malicious intent. Worst case scenario, if "they" tell me I need to turn it down, I'll say fine, you bring the meter & tell me when I'm legal.
I think you can expect a mile from a height like that; even legal. However, while you'll have good line of sight, the "shadows" will be significant. You'll have dead spots behind buildings, trucks, trees, hills. We call it picket fencing.
Sure. I guess that means it's more useful from peoples' homes that happen to be stationary in a high-signal zone, than for cars driving around, but meh.
Since you seems serious, send me the GPS, or address, and height above ground where you want to radiate, and I'll send you a computer model of your coverage. Here's mine.
http://www.facebook.com/photo.php?pid=30093742&id=1254494962
That is VERY awesome of you.
I am really interested in doing this, and as I said, the TIME is way way more the barrier to me. Well, that and staying legal.
I have two options for location. Both antennas would start atop a 2-story building.
Manchester:
42.96670, -71.46598
42.9663092 -71.4668033
N42° 57.9786', W071° 28.0082'
Concord:
43.19698, -71.55226
43.1974796 -71.5524705
N43° 11.8488', W071° 33.1482'
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send me the GPS, or address, and height above ground where you want to radiate, and I'll send you a computer model of your coverage. Here's mine.
http://www.facebook.com/photo.php?pid=30093742&id=1254494962
Dude, that's your profile pic, not a map :)
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Sent 2 to your gmail. Let me know if they make sense. I'm working on making a version that shows the streets better.
Facebook friends can see my coverage map.
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Sent 2 to your gmail. Let me know if they make sense. I'm working on making a version that shows the streets better.
Facebook friends can see my coverage map.
That's your FM though, not a P15 map, right?
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KDus has been sending me maps and I have to say he is *awesome* for doing so much research, it is hugely appreciated.
So far it's been FM maps. The range is awfully damn small, just on the borderline of what I'd consider "worth it", but not as bad as I might have thought either. About 2/3 of a mile. In Manchester, that would almost -- almost -- let me hit the Verizon center :shock:
I'd love to see what kind of range AM would give with the same presumed-legal 100mW.
If this does get off the ground, I'd be broadcasting LRN.
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That map on my facebook is old and from a previous location.
I'll work on a new one. Currently, I'm at about 4 watts with a slightly directional antenna.
As I get better at it, I could make one for all affiliates.
I'd really like to know how they compare to real world performance.
Edit: Just updated map on my facebook, made adjustments that more accurately depict the real world.
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Marc Stevens often pimps the part15, liberty1640.com stations that he's on. I'll bet you could talk with the guys that are actually using the equipment and hear what they have to say.
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Well I do have to admit that the Rangemaster has it hands down when combining the units for extending range. The thing that bothers me about these units is the non-regulating power output.
With a properly built and matched antenna system conforming to the Part 15 219 rules, there should not be any reason for adjustment of power.
But the things are certified so thats a good thing. :)
I have devoted a lot of time to Part 15 219 intentional radiator "tinkering", sometimes getting results far exceeding the design specs, and other times results that were less than favorable. This is why I have shifted my operations on my AM side over to Carrier Current.
But I still have the good ol 3 meter setup (home made) out there on the 3 foot pole and fire that up once in a while. Using a CCUFF C-QUAM board w/o the added final (aprox 45mw max) the whole thing covers about 3/4 mile on dry days, and about 1.7 miles when it rains.
Still that does not come close to my CC setup....neutral loading, with 5 watts my station covers the entire city. Just added a recently ebay purchase of an LPB TX-25 25th anniversary special with its companion TCU-30 coupler. Whats cool is the thing is simply plugged into a wall socket close to the power panel in my home feeding the neutral line and is covering the entire city with a clean signal.
Here is a neat little CC transmitter constructed around tubes. I have built one of these and it has a very warm and smooth sound. Parts are easily to obtain and it has its own coupler system and designed to couple to the neutral line, bypassing those pesky road blocking transformers.
http://k6prk.org/CARRIER%20CURRENT%20AM%20TRANSMITTER.HTM (http://k6prk.org/CARRIER%20CURRENT%20AM%20TRANSMITTER.HTM)
RFB
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Perhaps to clarify part 15 FM and "power levels". Part 15 FM isn't restricted by RF power output, it is limited by field strength. 250 uv at 10 meters from the antenna.
There are no restrictions on how high you can mount an FM transmitter/antenna. So yes, mount everything high up for an FM operation and you'll have great coverage.
So don't get FM confused with the power input limits that are set for part 15 AM which is 100 milliwatts into the final stage.
You could run a 20kw FM transmitter and not be in violation, just as long as you do not exceed the field strength limit. You could be your towns most powerful FM station with the smallest coverage :lol: :? :shock:
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You could run a 20kw FM transmitter and not be in violation, just as long as you do not exceed the field strength limit. You could be your towns most powerful FM station with the smallest coverage :lol: :? :shock:
Well...yes you could....if you had a proper dummy load to handle that power as well as a 3 phase 220vac utility drop. Not exactly common in the A-typical residential home. Oh dear lets not forget about the ventilation/heat exchange requirements too for such a transmitter!
A dummy load could be constructed from the suggestions found in any ARRL handbook. However I would also add a closed system of forced pumped coolant for the dummy load resistors. At 20Kw, even 1kw, will make those dummy loads heat up like a fireplace in no time.
Yep...one might want to put such a setup in a small storage building away from living space and studio as the transmitter ventilation system and dummy load coolant system will produce quite a bit of noise.
They dont seem so loud when out there at those remote tower sites but put one inside a residential setting and they are incredibly loud! Got good earplugs? :P
RFB