Foliage effects FM but not as much as UHF. I do remember 800 Mhz was really effected by foliage. At part 15 FM it too is possible.
I've found the C Crane transmitter highly variable in its range (I've owned several of the original models - in my reading, it seemed that everyone went straight to the 'secret' power adjustment in the battery compartment and cranked it up to get semi-decent range; otherwise, you might get a few feet range, or you might cover your house, based on the luck of the draw).
I also suspect the Whole House transmitter is the same. I only have a Whole House 2, and it might be a dud, but it performs very poorly, far worse than other Part 15 certified devices I've owned and own.
When you have a mass produced transmitter, and it is certified to produce at maximum a certain field strength, you want to ensure that each and every one is under that maximum. I know if I were doing it I would have a fudge factor built in to make sure that no transmitter goes over that limit.
So this is going to be tricky to find a transmitter at 95% value but if we do find it I want to see the range of a fully part 15 unit. More tools to use so we can petition the FCC. Heck that alone could be in our favor.
Ya'know
We may learn somethings about Rf
attenuation through different matterials
that nobody stopped to think about.
You never know. We are dealing with
very very low power levels here.
Not to mention the signal to noise slopes
on a lot of different receivers, and how they
differ. But as a science guy - I find the attenuation
thing to be very interesting regardless if it's Part 15
or something else.
So ya never know - we may discover something new -
maybe - maybe not.
Brooce, WLP
RE: Reply #31 above: ... Foliage effects FM but not as much as UHF. I do remember 800 Mhz was really effected by foliage. At part 15 FM it too is possible. ...
Just curious, how many operators of unlicensed systems using the FM broadcast band have such foliage present within 3 meters of their transmit antennas, where the FCC references most of the non-compliant fields shown in their FM NOUOs? Close to zero, probably.
And even if such foliage/attenuation was present, that would aid their case before the FCC, not degrade it.
RE: Reply #25 above: ... Mr Rich is not a part 15 station hobbyist, yet he hovers around commenting negatively about what actual hobbyists do.
I do not comment "negatively," but based on science. Science that has not been disproven, and apparently that has not been well understood, by some.
I looked at the Ramsey chart for part 15 and it is interesting to note that it can cover up to a hundred acres. This was a chart that was meant to guide those that don't have the Potomac field strength meter. It is interesting to note that if you ask a field agent over the phone on the FCC's phone number about a part 15 FM station covering a small neighborhood they don't have any problems with that so long as there is no interference being caused. This was something that surprised the heck out of me. Plus contrary to some belief part 15 did include the venture or the experimentation with FM transmitters. It's interesting to know that the rules do state the 250 Micro volts per meter but too that the FCC does understand that not everyone has the ability to measure the strength. So when asked about covering a small neighborhood they said something about 100 acres. This is a far cry from a hundred fifty feet. I understand that some have gotten citations for going far less but there may be some other variables involved. I'm not denying that the rules are the rules but it seems to that the FCC is a little relaxed on some of those rules. Thus explaining why unless there is interference involved the agents usually don't care of a small coverage of a neighborhood or campground. If you look at a map of 100 acres that covers quite a bit of ground. It could easily cover a few city blocks. This validates why the Christmas town in Michigan was never cited because their Transmitter certainly covered close to 1 quarter mile. Again this is another case in point for why I would like it more set towards power levels and a inside and or a certain length or height above ground as a restriction. As I done some more research I found out that this very same thing was talked about on a well-known anti fm website. Radio brandy had asked an agent about covering an entire neighborhood in the legality behind ab. The FCC agent stated that they had no problem with an FM station or should I say part 15 FM station covering a small neighborhood or campground and then talk about 100 acres. So bring some more light on this whole subject. It could explain why the sainsonic was certified at one time. Though it may had went over this field strength level a little (at high power)it did not cover more than 100 acres. I can't prove it but I have a funny feeling that the rules are going to change especially with the new expansion of the fm band if it does take place. However I still want to lobby for this to be written down in black and white. I am sure some agents with their hair up there but will still site you depending on your area if you are even the slightest bit over 250. I'm still willing to say though in areas that are not Metro and because of the Christmas light Transmitters that do go a bit over the 250 Micro volts per meter that this is going to change. Do the research you'll see it. Also do the research on the 13 year old boy who had an FM transmitter on like the 20th floor and went out for several miles. The judge ruled in his favor. The NAB might have their rolls out there but the rules are changing its something that they really don't want you to know but do the research you'll see it its in black and white. I would still ask for something like New Zealand and have a few channels dedicated to hobby Broadcast maybe when the fm band does expand we can ask for 87.9 an 87.5 and maybe 87.7 to be a part of it.
... It is interesting to note that if you ask a field agent over the phone on the FCC's phone number about a part 15 FM station covering a small neighborhood they don't have any problems with that so long as there is no interference being caused. ...
What verifiable proof exists that the quote above (if true) states the statutory/enforcement policy of the FCC for unlicensed FM broadcast systems?
By questioning TheLegacy's honesty one opens his own statements to question.
We are being lectured by an RF engineer, not an FCC qualified attorney.
If you want to be brave you could ask yourself. Scared to call use an app like TextMe and watch enough video ads for 120 minutes. You can then call the main Fcc number and see what happens. I will say Radio Brandy is well known. If you are grossly over and they pretty much can tell by your transmitters audio signature. Yess just as you can tell certain CB's a certain agent can have an educated guess as to what type of transmitter you may be using by the characteristics of your signal and base that on earlier experiences with other possible violations. You won't fool them. They know the transmitters out there. Your attitude on air and with the agent makes all the difference too. By all means do research but it makes sence. Especially kits.
Now those who call the FCC because a station can be heard through a few blocks all this does is hurt everyone. I still urge the written rule be changed. It makes no sence to spend thousands for the equivalent of a Bluetooth speaker.
We're getting slightly off topic here.
And we don't want to give the impression to anyone that going over the 250uv/m at 3 meter field strength limit is OK.
100 acres, by the way, is a plot of land 2000 x 2000 feet. If you plant your transmitter right smack dab in the middle, then it's theoretically possible to cover most of that area (a circle 1000 feet in diameter) but not very likely (you'd need a highly sensitive car radio, or something like a MacIntosh tuner with an outside antenna, as well as direct line of sight - the field strength at the edge of that circle would be a little under 2.5uv, assuming no obstructions).
You explained it better. Now what about a Tecsun receiver like the one that received WXTZ? Also I was just trying to inform here. Mr. Bruce did prove there is ways to get listeners on a part 15 FM transmitter and it sounded good on that Tecsun radio.
I can't even seem to find a CM-10 to purchase, except from a fitness supply place that sells it for just shy of $400. Once the CM-10's are gone there will apparently be no more. I see the next legal Part 15 transmitter they offer comes in at about $500. So I'm thinking for a low budget FM operation Decade may be out of the equation.
I have the equipment and plenty of open real estate right here to do all sorts of testing, just nothing to test.
Tim in Bovey
Have you looked on Ebay? Also SainSonic is still selling the AX-05B and as far as I can tell FailSafe is also selling theirs. So I con't know why Decade is dropping out of the part 15 FM business.
Are the units mentioned certified?
I don't think Decade is getting out of the Part 15 business, just discontinuing the less expensive model. You can still get the MS 100. At $495. (at least that was the only online price I could find)
http://www.decadetransmitters.com/en/transmitters/ms-series
Tim in Bovey
There are 50 CM-10s left from Decade. They're on holiday till Mon. Aug 3.
I'm thinking of getting another for an extra....think if you call direct and talk to Michael Carrier I think he would be willing to drop the price a bit.
Also the price of $199 is I believe Canadian dollars so with the exchange it will be about 20% less for you.
Mark