I checked out the I A.M. webpage info and went through it with a fine tooth comb. And, there it was. At the bottom of the description for the ATU, they mention that increased range can be obtained when using the ATU by connecting the ATU ground lug to a suitable ground connection such as a building ground, water pipe or ground rod.
They go on to mention that the 10 foot rule usually applies to include the length of the ground wire used. No mention is made of the grounding afforded by the coax sheild.
The sample installations they show have the ATU mounted on a chain link fence and on an antenna mast pipe. The fence is about 4 feet high but you can't tell how high the antenna mast pipe is.
Seems like they are being very subtle about the "extended ground" questions.
And I Quote:
"For best performance, you may want to attach a wire (not supplied,) from the the Ground Wire Connector on the top of the ATU to an earth ground.
Some examples of earth grounds are:
• The center screw that holds the cover on a wall electrical outlet.
• Plumbing, water pipes (metal).
• A copper ground rod driven into the earth.
Please note that Part 15 FCC regulations do not allow an antenna in excess of 3 meters in length and most usually the ground wire length must be considered by adding its length to this total antenna measurement calculation."
Yes, kc8gpd, your situation definitely is part of real experience for some part 15ers, and here is an idea I have held for a long time that, if doable, might offer a solution:
Imagine a pipe about 10-inches in diameter running either on an outside wall, like a downspout, or an inside location, not unlike a plumbing stack, but this pipe would be packed full of dirt all the way down into the actual ground, however far below. The center of this earth-pipe would have a very thick-gauge one-conductor cable all the way down, attached to a 10-foot ground rod in the earth.
By doing this we could "raise the ground."
Maybe it could be installed as a "plumbing" or "drain-spout" project.
Here is another interesting point from the I A.M. manual.
Apparently they have circumvented the antenna lead wire length restriction as follows and I quote:
"The model ATU Outdoor Manual Antenna Tuning unit is FCC accepted within this certification as serving as the final output stage."
That would seem to rule out the coax as being the antenna lead as the antenna connects directly to the internal components of the ATU.
The coax then simply connects the "exciter" to the "final output stage" of the system.
Wouldn't it therefore follow that we can assume the same when feeding our "exciter" signal from all these part 15 xmitters into our "final loading coils?"
It's been there the whole time and we just haven't seen it.
This means we can all bring our transmitters indoors.
It's really good to have you back -
I'm sorry that you had to go through
so many "Life Reality" situations.
You have been very brave.
I hope you enjoy being back on the board.
It looks like you already are doing that.
Very Best Wishes To You,
Bruce, DOGGRADIO STUDIO 2
(Formerly, Micro1690/1700)
"Wouldn't it therefore follow that we can assume the same when feeding our "exciter" signal from all these part 15 xmitters into our "final loading coils"?"
Hold on there....re-read the quote out of the iAM manual quoted in the previous post:
"The model ATU Outdoor Manual Antenna Tuning unit is FCC accepted within this certification as serving as the final output stage."
I think a very important thing to note and keep in mind is that the iAM manual is NOT in any way, shape or form any part of the actual FCC rules!!
The statement made within the iAM manual about the ATU serving as the final stage is accepted within the certification of the transmitter, thus that ATU cannot be used with any other transmitter, nor can that transmitter be used with any other ATU...pointing back to what I have been saying all along about the TH and it's ATU..that it is certified as one whole system under that one certification number.
It also follows the basic guideline in Part 15 of the rules that a certified transmitter cannot use anything else that did not come with the transmitter or was not part of the unit during certification.
I do not think that anyone can take what is only applicable for the TH/iAM units and their ATU's as being applicable to just any Part 15 AM transmitter and start running coaxes out to their 3 meter antenna systems. First off, your transmitter needs to be certified and certified in combination of an ATU antenna system like that of the TH/iAM unit.
RFB
i really say two things...
1st and most important flood the fcc in washington and the district offices with FOIA requests for that 22 page field manual. there is something in there they don't want us to see that would possibly put mucho egg on their face especially with situations like kenc.
2nd we need to stop the bickering over it and get the ground lead restrictions removed by forming our own lobby. hamilton, phil b., chez radio, radio systems, and hobby broadcaster are good candidates to spearhead such a lobby.
maybe extending to 15 meters like TIS is allowed and changing the input to total un modulated input instead of total input and cap the positive modulation at 125%+ to keep the CB mentality from pushing wattage level power while maintaining 100mW unmodulated input
Agree with most of your post Robert, cept for the selection of the spearhead of a lobby group. They may be good candidates, but they are all business oriented and I think there has been enough representation for change in the overall rules already spearheaded by business interests and steering everything in the wrong direction.
There has to be a heavier grass root, public level interest involved along side industry, even representation and interest and voice. If it cannot have that, what would be the point?
RFB
i also think that 15 meters should not include things such as the diameter of capacity hats, capacity globes, or loading coils whether helical wound or base loaded. it has been proven that these do not radiate only add capacitance to the antenna requiring less loading and more evenly distributing rf along the radiator.
simply height from Tx RF out to tip of antenna and ground is length from TX/Tuner housing to earth ground.
there should also be leeway for a field agent to make a judgement call in situations such as deed restrictions, ccr's or apartment situations prevent outdoor ground level mounting. in which case going from the chassis to an indoor electrical ground point such as ac ground as the ground lead since indoor / in wall grounds are unlike to radiate much beyond the building walls.
i have verified this theory myself with such an install in a typical structure apartment building. my range was 1/8th to 1/4 mile to a grundig g5 portable radio and very quickly dies out into the static.
typical ground mounted outdoor install over a good ground plane yield 1-2 miles.
WOW
These are great Ideals. I know that5 years ago when I wanted to set up
a station. Boy the FCC was stating to me I should buy an FCC certified
station instead of getting a kit. They said that I would have less troubles,and
if ever called on it all I would have to give is the FCC ID #.
They were trying to tell me that the large local radios stations could give me
a hard time and then report me s a pirate Radio Station.
Then I was told the FCC has to investigate all reports unless you can give
them a FCC ID # off your transmitter. I was told that would stop a
investigation as soon as they heard you were using a FCC approved transmitter.
So this bring me to my next point,so if we use our kit transmitter. And a large
radio station reports that their is a Pirate radio station in the area.
Are we going to have the FCC on our door steps because we built a transmitter
from a kit instead of paying a really high dollar value on a FCC approved
transmitter.
There is some pretty good transmitters that have no FCC ID.
SSTRAN are good ones,and several other companies make them also.
Let me just say. I was told the names of transmitter and all their FCC ID's
by the FCC. The strongly encourage me to stay away from kits and
buy a FCC approved transmitter. This was 5 to 6 years ago.
My personal oppinion I like some of the non FCC ID transmitters more than the
certified ones.
the SSTRAN 5000 sounds great. I have a Ramsey transmitter that works great.
Now I was told it was over the power limit on input power.
That was easly change by taking out the 2 ,10 ohm resisters and placing
a 50 ohm resister in the place of them.My power input dropped off to 100.1mw DC
input to the final .IT still got out great.
I also placed a 12 volt regulated power supply on it. It actually outputed 12 volts,and not 13.8 volts.
Anyways There is some good non FCC certified transmitters on the market.
They all meet FCC rule part 15,ut large AM broadcast stations could make
problems for users of these transmitters.
Well this is what I was told by the FCC when I wanted to get real serious about
setting up a radio station.
SeanKW40
Agree. But I think most of the issues are caused simply by lobbyists swaying the rules to their advantage...hrmmm...sure sounds familiar with a lot of other areas of our governing entity!
RFB