Said: "Preferably also with an understanding that such an approach is very unikely to provide the hoped-for "proof" or assurance desired for it."
That kind of remark could discourage anyone from pursuing the radio hobby.
I think that's the idea.
Earlier clips from this thread by two different people:
1. That kind of remark could discourage anyone from pursuing the radio hobby.
2. I think that's the idea.
Which is better for the development of Part 15 ?
- Following and promoting an incorrect technical understanding that could lead a user to FCC problems.
- Learning as much as one can about the way these systems really operate and are measured, so as to avoid or at least minimize possible FCC issues.
YOU have already posted that operating a certified device is not enough to show compliance with FCC Rules even if the device is operated in accordance with the user manual. It is painfully obvious that equipment used to verify compliance is out of the reach of the average hobby operator. Tim in Bovey has demonstrated that even certificated equipment exceeds the Part 15 limits on the FM radio band. So in effect yes you are discouraging operation because the casual Part 15 operator has no way to defend himself because he cannot demonstrate compliance especially in the FM radio band.
RE: ... the casual Part 15 operator has no way to defend himself because he cannot demonstrate compliance especially in the FM radio band.
And if so, is it a better service to...
- tell Part 15 FM users about this (which to his credit, Tim did, and documented).
- lead Part 15 users into thinking that they can concoct some relatively easy and cheap means to "prove" their compliance to Part 15 (at least to their own satisfaction).
Unfortunately, hobbiests try for some easy and cheap means to try to be compliant as we know having a very expensive meter and then having the way to set it up and the expertise to use it is not an option for most of us.
The only way the radio that Carl uses could give some indication of compliance is if you take a field strength meter such as what Tim has and measure 250uV/M at a certain point and then have the Tecson radio with the antenna the radio came with, say, fully extended and horizontal as the meter's is at the same spot and look at the reading on the radio and note the numbers. Then you have something to go by(roughly) BUT you have to know the field strength first
Without that The Tecson as Rich has pointed out is not a way to know.
250uV/M at 3 meters means that at 3 meters from the antenna the EMR at that point will create a voltage of 250uV accross a length of wire 1 meter in length.
The Tecson isn't measuring that at all.
Not really trying to sound like Rich but I do understand why we all look for some simple way to judge compliance.
There is a popular Low Power Radio Guide page on the FCC Website that, with full understanding of the inability of the hobbyist to make serious "pro" field readings, estimates that the expected transmission range is typically around 200-feet.
It is plain and simple that in my earlier reports on how I went about determining my 125-foot range I used the "200-feet" as my guideline.
All this other wrenching of the thread to insist that "it can't be done" ignored everything I said along the line and does no more than crush inovation.
I do not intend to take advice from people who are not trained in FCC law nor true representatives of the FCC.
The FCC understands that the radio hobbyist has no realistic means of 'proving' compliance. That's why they published the technical bulletin that states that you will be considered to be compliant (with the Part 15 FM rules) if your signal travels no more than 200 feet.
Unfortunately, no radio is described. Nor is the type of signal (city grade, just barely heard, etc.) also described. That means that the broadcaster has to do some interpretation of the bulletin.
I'd go with that, keep a copy of the technical bulletin alongside your station, as well as your interpretation. If you can use a certified transmitter, do so. And if the FCC comes a calling, be respectful and do what they tell you to do.
It's not hard. Or scary.
Now, the copyright police - they're scary.
I like ArtisanRadio's approach to Part 15.239 FM signal strength.
Rich mentioned avoiding FCC problems. What signal strengths are listed in FCC NOUOs? FCC Part 15.239 NOUOs from February through June of this year that state a specific signal strength are of three types:
1) Three list a signal strength at 3 meters ranging from 1,600,000 to 3,500,000 uV/m.
2) Seventeen state >250uV at distances from 121 to 1137 meters.
3) Six list >250uV.
I assume the first type were measured at some distance other than 3 meters with the signal strength at 3 meters being calculated. The second type is simple; exceed 250uV/m at any distance greater than 3 meters and an NOUO is issued. The third type is not clear as we don't know the exact signal strength. I suspect that like the second type they grossly exceed the limit.
Naturally as a responsible matter of curiosity we want to be kept aware of FCC actions regarding unlicensed stations.
But it is also significant that over many years NOT A SINGLE MEMBER OF THIS WEBSITE HAS RECEIVED A VIOLATION NOTICE from the FCC!
Therefore the constant harpings aimed at hobbyists on this website virtually suspecting violations around every corner are lunacy and are tantamount to yelling FIRE in a crowded theatre.
Needless fear is being churned up and it's not a healthy way to do business.
3,500,000uV/M......What was he/she using!
Still seems that most of these are not just slightly over...even 250uV at 121 meters is quite a bit over. That's several times over even the Canadian limit.
@Carl...I think a few years back someone from this website got busted. The Crow I think was his station name? Do you remember this?
Mark
Mark remembers: "I think a few years back someone from this website got busted. The Crow I think was his station name? Do you remember this?"
Yes, it came into memory after the earlier post, although I do not remember the details about what happened.
There was very good follow-up here on the forum when The Crow himself signed on to tell the story of exactly what happened. It was a very interesting account of an encounter with an FCC inspection.
The whole drama is embedded somewhere in the database.
I did a search for The Crow, and reread the thread that described the situation. It appears that the operator knew that he was running illegally, so it really doesn't fit into the scenario of unintentionally operating an 'over the limit' transmitter.
I suspect that if a Part 15 broadcaster keeps FM range within some reasonable interpretation of that 200 foot limit, they would not have any issues with the FCC, even if investigated. Particularly when using a certified transmitter, which shows on yet anther level that you are attempting to be legal.
The dBu readings taken up to this point, measuring signal strength out to 125' from the exact center perpendicular to our Decade GP32 horizontal antenna utilized the FCC's published advisory that part 15 hobbyists could expect about 200' of range from an FM transmitter.
Rather than claiming the full 200', we only measured to the northern boundary of our campus at a public street, which worked out to 125'.
In the next stage of our process we will be lowering the power until only our specific needs are meet and no excess energy is radiated into unused airspace.
KDX employs part 15 FM for monitoring our worldround broadcasts at our control desk, and this has already been found to be served by even lower powers than recently explored.
As it happens these measurements will resume during the two weeks commonly known as "the holidays".
We've got to lay in some egg nog.