Does anyone know if there are any part 15 installers. I've contacted some companies that install LPFM, but when they hear that I want to install a part 15 station, They said they have have no interest. is there any in Philly that want the work, AND WANT TO INSTALL IT CORRECTLY?
Not going to be easy, if even remotely possible to hire out a company that installs licensed stations who would be willing to install a Part 15 site.
However hope is not lost.
You could call a local two-way communications company and talk to one of their techs. Perhaps one of them might..as side work and not necessarily through the company, or perhaps the two-way communication place may do the job and mark it as a service call or antenna installation, which basically that is what it would be. And the two-way tech would have appropriate equipment on hand to make measurements.
You may have to "fish" around for such a tech who would be familiar and willing to do the job, but I believe this would be your better choice and most likely to be successful in finding some sort of professional installer to set it up for you.
RFB
The part15 map on the front page of this site shows some part15 stations around Philadelphia, you might want to try clicking on them and making contact, maybe you could luck out with someone nearby willing to help with your install.
Another possibility is a licensed ham operator.. there's several around you as well, try this link: http://www.city-data.com/aradio/lic-Philadelphia-Pennsylvania.html
Does anyone know if there are any part 15 installers. I've contacted some companies that install LPFM, but when they hear that I want to install a part 15 station, They said they have have no interest. is there any in Philly that want the work, AND WANT TO INSTALL IT CORRECTLY?
First where are you installing it?
Personal use, business, school, Church?
What are you trying to do, play music, voice?
How far do you think or wish you want to transmit?
Did you say AM or FM? I assume FM based on your post.
What's your back ground? You can easily do it yourself IMHO.
Here are realities of Part 15 AM and FM, range (legal, done right), is limited.
Part 15 for FM is easier to set up than AM, because of the much shorter antenna needed for VHF Freqs for FM (88-108Mhz) verses MW Freqs (530-1700 Khz) for AM radio. AM has the potential to carry further if the installation is done right. That last part involves a very well tuned antenna and great ground system, even Pros have a hard time getting right.
FM antennas are so short they are often directly off the back of the unit (no set up). There are off the shelf outdoor FM transmitting antenna you can buy, simple to set up, follow the instructions in the box. However you have a FCC limit in absolute Part 15 FM radio range. Installing a matching outdoor antenna is not illegal in itself, but it would likely exceed Part 15.239.
I am no FM expert, but you are limited to 150uV/m @ 3m (9.8 feet), when using even channels. What does that mean? 150uV/m is a good strength any FM radio should hear clearly, LOS (line of sight). Keep in mind this is TEN FEET! What will it be at 98 feet or 980 feet? Really low. So range is regulated or limited by edict, regardless antenna or the transmitter power. How do you know your field strength? You don't unless you have some fancy gear. You can't exceed field strength on 100 mW to badly, but an good outdoor antenna will no doubt exceed this limit. The regulations are interpreted by the FCC. Even if your station is legal, if you interfere with anyone you can be told to shut it off. This is why 2nd parties don't get involved with it installing these. If they know their stuff, they know it is a can of worms. Part 15 is for learning and personal private use, aka for hobbyist. It was never meant to be private stations with any range. Thus the regulations are very restrictive to these ends.
If you don't get a complaint than all is good, no matter what your field strength or range is ... If you have many watts of RF power, with an antenna on a tall tower, expect unwanted attention. Again the FCC does not police this, they work on complaints. If you have 100 mW with a modest antenna, inside or outside, you will be OK.
AM does not have a range limit (debatable), but has it does have antenna and power limit that effectively limits range. FM is going to sound better for music, but "oldies" recorded back in the day had limited dynamics and Freq bandwidth, so they sound fine on AM. FM is almost immune from typical static that affects AM.
I think your money will be best spent finding a FCC Part 15 approved transmitter (if there is such a thing for FM), but in no case exceed 100mW (AM or FM). I think the wholehouse FM transmitter is Part 15 approved (double check):
http://www.wholehousetransmitter.com
If you use a Part 15 transmitter it will have an approved antenna. You must use that Part 15 approved antenna. In the above WholeHouse model, the antenna is a built in wire antenna. The reported range of these is modest, as expected. FM is not going to be hard to set-up, but will have short range. You can buy a nice small FM transmitting antenna, some coaxial, a poll to mount the antenna on... set-up is easy. However it's almost assured you will exceed the limits. You can get on eBay and buy FM transmitters with way more than 100 mW (0.10 watts). You see them with 0.5 watts or 5 watts or 10 watts with antennas. They are cheap and you can throw that up and get some good range. It will not be legal. There are the people that get fines. It is a gross violation in very way shape and form.
Get a FCC approved Part 15 FM transmitter and antenna if possible, and don't exceed 100mW. If there is a Part 15 FM transmitter and antenna combo, it's going to be something very simple and easy to set up, like opening up the box and plugging in the power into the wall outlet and the audio source into the audio jack.
If you have dreams of transmitting to the whole town or much less your whole subdivision, forget it. Part 15 might cover a block of close spaced homes. A LPFM station (10 watts or 100 watts) is about $5000-$10,000 to set up. You need FCC approval to get a license. It has to also serve the community, be non profit and available for people in the community to use, aka public access .... I can receive two LPFM stations. To give you an idea the FCC assumes the useful range of a 100 Watt LPFM station is about 5 mile radius. I am about 8 miles from one and almost twice that from the other LPFM station. They are both on the same Freq, 107.9 Mhz! I get them because I have a super sensitive FM receiver and directional antenna. They come in kind of weak but listenable. In fact there is a third station on 107.9 Mhz, a high powered commercial station 89 miles away. The three stations are in three separate directions. So the directional antenna allows me to hear all three. Unlike AM, FM receivers will lock in on the stronger signal. AM stations on the same Freq tend to mix. However with a direction loop antenna you can some times block one and aim at the other station.
How far does legal Part 15 AM go? That is a debatable controversial. However if you are doing it well, a mile might be reasonable, however plan on much less. Some people claim 3 miles? That would be extraordinary. Most people that set up a simple Part 15 transmitter with the 10 foot long approved antenna are lucky to cover a small residential home. The better systems for range is the "Range Master" and the "Podcaster". They are a combo of transmitter + antenna that mounts outside. You can install these fairly easily. Having FCC approval will help if you get in trouble. The most likely violation you can get into is a ground wire that is too long (more than a foot or two). Their web sites and manuals are available on line. Review them. Any one who knows which way a screw driver works and has used a volt meter can install these.
The reason no one wants to install you a Part 15 system is because the rules are kind of vague, some times seem contradictory or even impossible to comply with. If you are getting any significant range approaching a mile, AM or FM, the FCC could find fault with your set-up some how. Even if they can't, just because they can shut you down if there is a complaint. The most likely complaint would be from a nearby commercial station. The obvious thing to do, find an unused Freq. Above 1610 Khz to 1710 Khz in the AM band is pretty sparse. There are only about 54 stations in the whole country on these 10 Freqs, coast to coast. Where lower Freqs might have +40 stations on ONE FREQ coast to coast. The golden rule, don't interfere with anyone. The down side of using the high AM Freqs is older radios do not tune above 1610 Khz. I have old Tube AM radios I play with. AM radios made since 1993 have the ability to tune 1710 Khz.
Good post Jet pilot. I found your parting comment curious though..
Above 1610 Khz to 1710 Khz in the AM band is pretty sparse. There are only about 54 stations in the whole country on these 10 Freqs, coast to coast.
I find that I get a lot of stations coming in on AM between 1610 and 1700. More so at night, but practically across all these bands.. A few are in spanish.. Am I hearing pirates or what?
My radio is just a Sony CFD-F10 (AM, FM, CD boombox) and I'm in Georgia.
Above 1610 Khz to 1710 Khz in the AM band is pretty sparse. There are only about 54 stations in the whole country on these 10 Freqs, coast to coast.
This is true...to a point. There are no where near the number of stations in the upper portion (expanded) AM band from 1610 to 1700 in the licensed services. However, there is one thing you did not point out which is critical, no matter if one is transmitting on the frequency or not.
They are called TIS stations (Travelers Information Stations) which use the 1610 channel in the expanded AM band. STAY OFF THIS FREQUENCY PERIOD!
The reason why is that the FCC considers this frequency taken even though a TIS station may not be on the air in your location. This does not mean you cannot use 1610. But if one were to go on the air, it is most likely it will be assigned this frequency and you will have to change your frequency. Licensed stations have all the rights and it would be pointless to pick this frequency, begin programming, and then suddenly a TIS station goes on air and ruins your station imaging and so forth. Plus having to re-educate the radio listening audience to find your new frequency. Just more troublesome than anything, as well as having to re-tune and even having to re-construct your antenna system and ground system if you have to change frequencies.
If a TIS is on the air in your location, or may be proposed, choose a frequency at least 30Khz away from 1610..or any other station for that matter. Follow the standard station channel spacing and this will also save you the trouble of an inspection and possible violation. Just because there may be some distant station only 1 or 2 channels away from your chosen frequency, does not mean that there is no one listening to it. Someone may have gone to great lengths to set up an antenna to receive that distant station and with yours transmitting so close to it, would cause potential interference and BAM....here comes the FCC field agent to ruin your day.
So for example...lets assume there is a TIS station on the air in your city, choose a frequency no lower than 1640. If there is a licensed station that comes in during the night time sky wave..say on 1650, then choose a frequency from 1680 or 1700.
Now for the frequency of 1710. You can transmit on this channel, however there are further limitations on this frequency, mostly occupied bandwith limits and modulation. This frequency is limited to 6Khz bandwidth and lower modulation to protect the higher frequencies above 1710.
Read up on the FCC Part 15 rules very carefully. If you do not understand something within them, there are plenty of folks here at this forum who will be happy to help you!
RFB
There are Canadian stations and Mexican stations between 1600 and 1700kHz.
My understanding is that 1610 is protected in the U.S. for Canadian use.
Previously 1610 has been a popular part 15 frequency if available in your area, precisely because it has no U.S. full power signals.
TIS is assigned to low band 530 or to whichever extended band channel is open in a given location. For example, where we are 1610 is no good because we have a 5kW on 1600. The nearest TIS station is in a different state at 530kHz.
Correct any misapprehensions I may have.
Nope Carl, you are correct. TIS stations will be assigned to the lower AM band (530) if there is a licensed broadcast station within 30Khz below or above 1610. Again we must always remember the golden rule of station channel spacing, even the FCC sticks with this. This is why some TIS stations get assigned to the lower band more often if there are licensed broadcast stations on or near 1610. Some have been assigned channels above 1610, however this is rare since many of the licensed broadcast stations were "grandfathered" after the expansion of the AM band, which allowed them to migrate to this expanded set of frequencies, and many of them choose the frequencies between 1610 and 1650. Later on, more stations began to appear above 1650. It is not uncommon to be hearing licensed broadcasters who are new stations licensed AFTER the expansion of the AM band to be transmitting above 1650..for the very reason of the existing stations migrating to 1610 to 1650.
RFB
Hello. I sit here in Nigerian internet cafe ready to install your part 15 there in the U.S.
But my dog needs special vet papers for travel, so please send advance to my Cayman account.
Actually the FM limits are 250 microvolts per meter at 3 meters. Also, there is NO power rule in FM. The rule is 250 microvolts per meter at 3 meters. Now if you had an FM Part 15 transmitter that had 100 milliwatts RF output, that would far exceed 250 microvolts at 3 meters! It would be more like 900+ microvolts!!! A sure fire violation!! A typical FCC Part 15 certified FM transmitter will have about 20 mW.
AM does not have a range limit
Letter of the law wise...this is correct. Technically....the limits imposed on an intentional radiator (FCC Part 15.209) antenna lengths which is limited to 3 meters (9.8 feet) will be the limiting factors on range. However even with a mere 9.8 foot length antenna, with a good ground system and ground conductivity, ranges on Part 15.209 AM stations can reach 2 miles or more!
Regarding the debate about using FCC certified transmitters, there really is no reason, if you have the skills to do so, to build your own Part 15 compliant transmitter. The rules clearly state the specifications your transmitter must meet in order to comply with the Part 15 rules. The MOST important base rule to follow if your going to build your own transmitting equipment is this..."Good Engineering Practices". This should always be the forefront of your design and construction. If you follow good engineering practices and adhere to the technical specifications of Part 15, there is absolutely no reason why any FCC field engineer/inspector would give you any trouble. Simply follow the rules, from A to Z and you will be A-OK.
(edited to add more corrections)
RFB
This is an interesting article for any one interested in AM. It talks about the extended AM band:
"The FCC's AM Radio Failure" by Art Stone Feb 7, 2011
http://streamingradioguide.com/radiochat/2011/01/07/the-fccs-am-radio-failure/
There are 4827 of MW AM BCB commercial stations in the USA on Freqs from 530 to 1600 Khz (about 107 Freqs). That's about 45 stations per Freq. From 1610 Khz to 1700 Khz there a total of only 54 station coast to coast. That is about 6 stations per Freq in the USA. The FCC is not issuing new license in the extended band. It's possible you live near an "extended band" AM stations but less likely, compared to Freqs below 1610 Khz. Also with less stations throwing signals up in the air at night, there is just less night time DX noise. Give the AM BCB a critical listen tonight.
http://www.angelfire.com/wi/dxing/xband.html
Here is a great site, http://www.radio-locator.com
Enter your zip or enter a Freq and range you can find
all kinds of cool info.
When picking a free AM Freq to transmit on, there is no substitute to listening with a good radio during the day (when signals do not travel as far) and also at night. Also walk around the house and listen for noise. I have RFI below 600 Khz. I think it's the AC powered smoke detectors. I also have several strong local stations from 600-850 Khz. Lower Freqs tend not to be good for Part 15 AM because of our short antenna limit. The higher Freq is a better match for a short antenna (albeit still way too short). Most instructions for Talking House, Range Master and Podcaster recommend highest Freq you can use. Some just say you must use Freqs 1350 Khz or higher. Lower Freqs I understand have more ground signal range.
There are 50 Kilowatt "Clear Channel" stations, which stay at full power at night, often with an omni directional antenna pattern. You might want to stay away from these Freqs. At night they can come in strong, +500 miles away. The biggest gaps of "Clear Channel" stations is between 1210 and 1500 Khz. These are not protected for clear channel but have another issue... (see next Par.)
http://www.ac6v.com/clearam.htm#USA
The other Freqs that you may want to avoid are the so called graveyard stations. These are local stations relegated to only a few frequencies on the upper end of the band. They can broadcasting at night with reduced power. The Freqs are: 1230, 1240, 1340, 1400, 1450, 1490 Khz. All these little AM stations on a few Freqs tend to be noisy at night, with what some times sounds like a million voices from beyond.
Once you cut out the Clear Channel stations in your half of the USA, local stations and any Freqs that are noisy day or night, I think you will find the higher Freqs are best for most people. I go with 1380 Khz for my old radios (1600 Khz max) and local stations. I have about 8 Freqs from 1360 Khz to 1590 Khz I could use. In practice only a few seem to sound best day or night. You just have to experiment.
Actually the FM limits are 250 microvolts per meter at 3 meters. Also, there is NO power rule in FM. RFBurns
Right 250 microvolt per meter at 3 meters.
Here is a good table from one of the sites below for FM est range.
Distance (meters-feet)/ Field Strength/Total Reception Area
3m-10'/250 uV/314 sq feet (regulation max)
6m-20'/125 uV/1256 sq feet
12m-39'/63 uV/4800 sq feet
24m-78'/31 uV/19113 sq feet
48m-157'/15 uV/1.8 Acres
96m-315'/7.5 uV/7.2 Acres
192m-630'/3.7 uV/26.6 Acres
384m-1260'/1.9 uV/114 Acres (sensitive FM receiver)
768m-2520'/0.95 uV/458 Acres
1536m-5036'/0.4 uV/1830 Acres
The range will be shorter with a less sensitive FM receiver. 1.9 uV is a very good receiver. That is 1260 feet or about 1/4 th mile. So if you are getting a mile with an average radio receiver with typical whip antenna you have too much radiated power.
You are right power is not limited, but as you or some one else said, if you have 100 mW into an efficient antenna you will exceed the limit. However 100 mW into a crummy antenna might be OK. 100 mW transmitter power into an inefficient antenna might be fine? Bottom line is that 3 meter/10 foot field strength.
http://www.gate.net/~advradio/fcc.html
http://www.radiobrandy.com/part15fm.html
Last comment FCC violations for FM operators ten to one (or more) verses AM. I suspect because of the flood of cheap high powered FM transmitters and antenna combos from China you can get for about $100. I don't recommend it. Also any of the FM radio kits, like from Ramsey are fine. However if a person is not confident in "installation" I doubt they want to solder up a transmitter. That brings up a good point, you don't NEED a Part 15 approved transmitter. You can make your own design or build a kit, but the operator is responsible for compliance. The fun part is learning and getting the most out of the system with in the limits.
Good reference table for those who are not aware of the differences in field strength per given distance.
You are right power is not limited, but as you or some one else said, if you have 100 mW into an efficient antenna you will exceed the limit.
Well it was not me. But let's look at that. Exactly what limit would be exceeded? Let's also look at the rules regarding this particular issue.
The rules limit you to 100mW maximum power input to the final stage. The rules also limit you to 3 meters total antenna, lead and ground lead length.
So what are we going to be exceeding with a perfect 100 percent efficient 3 meter limited length antenna being fed with a 100mW limit input power?
Scenario...lets say a fully compliant installation averages about 1 mile range with that legal 3 meter antenna and legal 100mW AM transmitter. Then it rains and improves the ground conductivity and makes that installation's range extend out to 2 miles. Have we exceeded a limit?
Or this scenario....lets say a fully compliant installation is using a 1 percent efficient 3 meter antenna with a 100mW AM transmitter. The creative individual develops a 3 meter antenna with 3 percent efficiency. What limit have we exceeded?
Adding another scenario..for FM
Lets say someone with an FM transmitter, certified or home built, and both do not put out any more signal than 250 microvolts at 3 meters. One day its running while sitting on a table in a room, the next the individual hoists it up 40 feet. Did a limit get exceeded?
See my point?
There are no rules limiting efficiency or range. Saying that there is is saying we are all limited to inefficiency. At that point..what is the point in experimenting and discovering better things that work inside the established rules?
You can make your own design or build a kit, but the operator is responsible for compliance. The fun part is learning and getting the most out of the system with in the limits.
Indeed. But right there that statement totally rules out exceeding a limit when your working within the established limits of power/length/field strength...which is all that the rules state, FM or AM.
Something to ponder. 🙂
RFB
We never established what he wanted installed, but I am guessing FM.
I'm just talking about FM for the time being; except for us AM nerds, FM is the more common Part 15 installation. In the case of the FM limit, 250 microvolt/meter at 3 meter, that is the controlling factor of range. With all things being equal, if you put up a nice 5/8th antenna high-up (no ground wire issue), you can cover a 1/4 mile radius (1320 feet) and still not exceed the 250 uV/m at 3 meter limit. You can't escape path loss. Predicted area is for a 1/4 mile radius = Pi * r^2 = Pi * (5280' * 0.25)^2 = 5.47 million sq ft. Real legal range of 1320 feet or 1/4 mile in all directions isn't bad.
AM is range is harder to predict I have come to learn, and Part 15 rules more convoluted or restrictive, IMHO. MW propagation is affected by ground and atmosphere. There is such a large miss match in the optimal 1/4 wave antenna length for AM radio and the allowed length of 3 meters, to get the most out of the 100 mW limit , for "legal" (practical) range, you need to really pay attention.
VHF is LOS (Line of Sight) is better sy getting through walls with less attenuation. Part 15 for FM does not have antenna limits; integrated ground plane radials, with out use of an earth ground. A 1/4 wave, 3/5 wave or 5/8 wave FM antenna is fairly compact and easy to tune. So for ease of installation FM is the winner by far.
For this thread on "installation", a custom design and DIY home-brew is not the way to go. I'd say for AM get a "Range Master" or "Podcaster" (antenna integral); both are FCC approved. For FM I'd get an edmdesign transmitter and a Ramsey FMA200 5/8 Wave 3.4dB FM Broadcast Antenna (or equivalent can also be 1/4 or 3/5 wave), and put that at least 40 feet in the air. The EDM transmitter is adjustable from 1-100 mW. The money you spend on these engineered products will save you paying an "installer", which would not be cheap, if they're in the business of setting up radio stations.
The RECEIVER... The forgotten half of the equation
AM range is debatable. In my opinion 1 mile radius or 4 times FM is possible. I see "Range Master" claims 1-2 miles. If your ground is fantastic, you have a low noise environment and a super sensitive receiver, sure, but that's not real world. I'd be pleased to get a mile radius on my AM car radio. If the ground and atmospheric conditions are right, MW range can be greatly enhanced (as you know). FM tends to not change too much from day/night, wet/dry ground. However range depends on the receiver. If the receiver is not very good, then your range will suffer. For AM radio, a good radio with a tunable AM loop (Tecsun AN200 or Terk AM advantage) will help receive a weak AM station. For FM a really good FM receiver like the GE Superadio's or new CC-Radio EP are winners, in both AM and FM. My Kaito KA1103 is a great super sensitive MW/SW/FM receiver, but with one small integrated speaker and no tone control, it's not the best sounding. On earphones it's great, especially FM mono/stereo. The GE Superadio III with mono FM sounds fantastic with a large speaker and bass & treble controls. The sensitivity of the GE Superadio III on FM is great, but on AM it's about as good as it gets, even with out an external loop antenna. The SRIII is known for AM sensitivity.
For the sake of discussion, AM and FM Part 15 both offer different Pros and Cons. AM installation as I was saying is going to be more challenging to install, needing a resonant antenna and good ground (lots of copper in the ground), to achieve max possible range. VHF antennas have their own ground plane radials, no worry about how long your ground wire or coaxial is. Throw it up in the air and cut your transmitter power back as needed (some folks say about 20 mW is about right). FM mono is going to sound better than AM mono. FM stereo cuts range a bit, but stereo is better for music. Bottom line, there are big differences between AM and FM in how they work, RF propagation, type of modulation and Part 15 rules. The fun part for nerds like me is navigating all this.
Well for one, throw a 5/8 ground plane antenna on a 20mW FM transmitter and I can guarantee your going to throw out more than a 250 mV field strength.
Obviously at that point your going to cover some distance, even more if you hoist that up into the air 20 feet or more.
However if you want to really get real with the real world....you would have to cut back that 20mW output so far down to meet a 250 mV legal FM limit off that antenna that the TX would have to be mounted right beneath that 5/8 wave ground plane.
In either case...whats the point. You have to stay within 250 mV at 3 meters, doesn't matter if the radiating element is a piece of wire, 5/8 wave ground plane or a stack of c-pol turnstiles. Meeting the legal 250 mV at 3 meters is not any "about right adjustment" guessing game. The FCC is quite harsh about field strength with FM as they are with AM. Either way...the field engineer isn't going to guess your field strength...they are going to be measuring it with incredibly accurate test gear far beyond the realm of "about right".
We also have to take into account the fact that your average public radio listener and not the die hard radio freak, is going to have a receiver around sporting sensitivity to the likes of radio astronomy dishes. (exaggeration..I know :D)
Back to installation:
For this thread on "installation", a custom design and DIY home-brew is not the way to go.
That is a matter of personal opinion. A Rangemaster or Procaster is pre built...set design...no modification allowed. Can't do much there if you want to maintain certification of the thing.
Isn't anyone these days doing what I did decades ago, and still do, and actually build things?? 😉
What happened to the good ol days of drawers full of scattered parts and pieces and a messy work bench with soldering iron burns? 😀
But for this person wanting to install a Part 15 station quick and simple...then yes go with an off the shelf factory unit.
Want my opinion based on first hand experience from a 30+ year veteran of radio engineering in AM/FM/TV/RADAR and SAT as well as 30+ years of experimenting with Part 15.....go AM...you will be MUCH happier with the results...pre built gear or home made....legal or (and I don't recommend it) throwing watts.
Have you ever heard wide band AM? How about C-QUAM stereo? Are you aware that AM modulation basically has no frequency limit compared to even mono FM? There is only so much frequency of audio you can cram into an FM carrier before you deviate it to a point where both the TX and RX cant even follow it. AM...boy that IS a different puppy I will admit that!
RFB