The head of a consulting engineering firm wrote a letter to Radio World claiming an “AM Loophole” regarding the Part 15 AM rules.
http://radioworld.com/article/close-am-loophole/24329
The head of a consulting engineering firm wrote a letter to Radio World claiming an “AM Loophole” regarding the Part 15 AM rules.
http://radioworld.com/article/close-am-loophole/24329
JUST READ 15.209. LOOPHOLE CLOSED.
IN SELF DEFENSE: Perhaps my title should have been “Uninformed Engineer,” so it would sound less like name-calling. But the word “ignorant” is founded on the word “ignore” and of course he did sound-off before checking his facts, which he ignored.
Besides, as a faithful, true part 15er, I felt like we were being unjustly attacked.
Unaware In A Couple Of Areas
Well that consultant engineer is wrong in two areas.
Part 15 AM can achieve more than 200 feet and there is no rule stating Part 15 AM is limited to 200 feet. Obviously this fella is just as confused as some experienced radio operators are..they confuse the FM with the AM.
15.209
“15.209 (c): The level of any unwanted emissions from an intentional radiator operating under these general provisions shall not exceed the level of the fundamental emission. For intentional radiators which operate under the provisions of other sections within this part and which are required to reduce their unwanted emissions to the limits specified in this table, the limits in this table are based on the frequency of the unwanted emission and not the fundamental frequency. However, the level of any unwanted emissions shall not exceed the level of the fundamental frequency.”
The words “this table” references to the table within the link to 15.209 above.
That is talking about unwanted emissions..ie harmonics and spurious. It also clearly says “based on unwanted emission and not the fundamental frequency”. It is saying that our harmonics at the distance given by the formula 24000/F @ 30m.
Let’s use 1600 for an example. 24000/1600=14uV at 30 meters.
That means our harmonic must not exceed 14uV at a distance of 30 meters from the antenna. Translating 30 meters is 98 feet. So at 98 feet that harmonic/s better be in the noise floor!
Second thing the consultant is wrong about, the “loophole”.
The consultant describes this loophole as a Part 15 AM transmitter being “mounted and coupled” to a tall metal pole. Well I seem to recall one instance where a Part 15 AM transmitter was up on a tall metal structure and connected to this metal structure for it’s ground path. Did this “loophole” save that station from being taken off the air? It certainly did not.
The consultant is correct that the tall metal pole will act like a big antenna, due to it simply being a larger conductor than the intended radiator and the tall metal pole will become more of the radiator than the 3 meter stick above it…again why that well known station got tagged and for exceeding the 3 meter antenna/coax/ground lead thing with the way it was interpreted by the field agent. The choke dampened radiation off the tall metal structure but did not do anything in reducing that total length of antenna/coax/ground lead.
Until the ground lead issue is clearly defined by the commission, it is wide open to interpretation so anyone with even a certified Part 15 AM transmitter up on a pole or water tower clearly exceeding 3 meters very well could get tagged for exceeding 3 meters due to using that tall metal pole or structure as the ground conductor path.
And we all know very well that without a ground return path to the transmitter, the system simply just does not function very well.
RFB
Field Strength
ALSO the guy said in his remark “There should be a field strength limit.”
Well, THERE IS! That’s why I noted 15.209.
One Size/Measurement Does Not Fit All
Well this is a perfect example of how the one size/measurement does not fit all. There are tons of things that will affect that field strength and the consultant is applying the limit..the WRONG limit to the whole..which is incorrect.
RFB
15
It’s actually 15uV…not 14uV…typo…601…error!!
Can’t correct it in the post…editing limited apparently.
RFB
I Wish I Could Just Talk To Him For A Few Minutes, But
I can’t even get my wife to listen
to me. (And we have a good relationship.)
He didn’t even mention the 100 mW input/
less than 3 meter antenna plus ground
thing. A ground mounted set-up does well.
Why did he not mention that?? Maybe it’s
a good thing that he didn’t. I’m not
sure.
Connecticut is (or seems like) the nation
wide capital for pirate radio. I have heard
so many pirates on AM, FM, and even shortwave
here, I lost count a long time ago.
I had to move from 1700 to 1690 because
a pirate (or a guy with 100 mW and a
3 meter pole on top of a some big tower)
suddenly came on the air. The station
runs a foreign language format. That 1700
operation has been on for several years
now. I believe that the 1700 does not
comply with Part 15. Nothing has been
done about it, however.
There is another similar station running
on 1620. I don’t know where it is.
But it is similar in format. I looked
up 1620 on radio-locator.com. There isn’t
a licensed 1620 anywhere near here.
So from THAT stand point, I can understand
the guy’s frustration.
I don’t think anybody will be changing the
Part 15 rules that affect us. I think these
guys have bigger fish to fry.
In drafting these comments, I may have missed
something. I welcome your further comments.
(HUH, THAT sure sounded formal.)
Bruce, DOGGRADIO STUDIO 2
Manipulate The Truth
“He didn’t even mention the 100 mW input/ less than 3 meter antenna plus ground thing. A ground mounted set-up does well. Why did he not mention that?? Maybe it’s a good thing that he didn’t. I’m not sure.”
Because it’s convenient to ignore the facts and make up stuff to fit the situation of the moment. Much like how meaning to words are twisted and tangled these days (political correctness) from the phantom dictionary with blank lines after every word.
Left is right, up is down, forwards is backwards.
Don’t worry, I left my 2 cents in there and DID mention the 100mW 3m bit.
RFB
He is not a total
He is not a total twit:
http://www.rwonline.com/article/gonsett-born-to-rf-engineering/3182
Gonsett. He is a trust fund
Gonsett. He is a trust fund baby who has had everything handed to him in life. he has probably wanted for nothing. i have nothing against stuff being handed to someone and them having a good start, but it typically creates a lack of empathy for others and a lack of understanding the real world us 99%’ers must live by when everything is handed to you. he is probably one of those mentalities that donates large sums of money to 3rd world countries while at the same time pushing government to attack our social security and medicare programs and calling those who receive benefits lazy freeloaders.
it’s whats wrong with government.
Simple..Is It Too Simple
“He is not a total twit”
Credentials don’t mean anything when it comes to the real world..especially when it’s simple.
I’m sure the guy is a well versed and quite capable engineer. Hundreds of thousands more out there too.
These days it is the paper trail that is more important than the ability and talent..ie meaning the wall filled with plaques and awards and degrees are more impressing than the persons actual talents and abilities. Quite ironic isn’t it.
The papers and plaques don’t do anything but hang on the wall..it is the named person who either lives up to what those papers and plaques say..or they don’t. Since so many like to take miniscule of everyone else and turn it into a gigantic limiting factor..the same can be done here with this fella about getting Part 15 stuff completely wrong.
Sometimes the simple is too simple that it’s complexity becomes too complex.
RFB
Damage
Not sure ‘completely wrong’ is ‘completely accurate’. The thing is, the FCC, like any obedient federal agency, has to keep the game face on. For example, the official Public Notice put out in 1991 …
http://transition.fcc.gov/ftp/Bureaus/Mass_Media/Databases/documents_collection/pn910724.pdf
… looked for all the world like there is an approximate 200′ radius limitation for Part 15 AM, but we know of course, there is no such thing in the actual regulations. Not quite misinformation, but still damaging.
The operational institutions of government, rule by appointment, not election, seem to insidiously distance themselves from the public by disguise. They hope we’ll not notice the little man behind the curtain.
But it’s our fault, all of us, for allowing it. “We have met the enemy and he is us”. Pogo author, Walt Kelly, first used the quote on a poster for Earth Day in 1970.
Masks
Ya well that 1991 document, even in the year 1991, is not the actual rules they enforce. It is a mere “poster” as like that for Earth Day in 1970. Window dressing. A simple cover sheet. Basically a “FCC Note for Dummies”.
It means nothing. It legally upholds nothing. And when going by the actual rules, the two do not even come close to agreeing with each other.
What is used in the legal procedures..isn’t that 1991 document.
I find it quite funny that old rag has been used a lot as the basis to claim 200 feet is the actual rule when it is not…and those who do throw out that old rag know darn well it means nothing, but use it anyway to support their “OPINION”. Not saying that is what your doing Ken, I have seen it elsewhere and I just want to make sure here and now so there is no confusion, that document is NOT the rule/s nor does it even mesh when running the numbers based on the actual rules within Title 47 CFR.
Makes for a nice historical conversation piece though!
RFB