Well by now with all the posts I have read and the research I've done, I have come to a conclusion. If you take a good look at the Hamilton Rangemaster website, it clearly states that since their transmitter is FCC accepted and approved, the range is not a factor as long as you tune it to 100 milliwatts and using a 3 meter antenna. It boasts you can get several miles LEGALLY. It does not specify field strength limits.
Well by now with all the posts I have read and the research I've done, I have come to a conclusion. If you take a good look at the Hamilton Rangemaster website, it clearly states that since their transmitter is FCC accepted and approved, the range is not a factor as long as you tune it to 100 milliwatts and using a 3 meter antenna. It boasts you can get several miles LEGALLY. It does not specify field strength limits. With all the testimonials I have read on their site and the research I have conducted, I have not heard of any reports of the FCC shutting down a Hamilton Rangemaster transmitter because they are getting 5 or 6 miles out. I want to be sure that IF I bought a Hamitlon Rangemaster and tune it to the max allowed 100 milliwatts of power with a 3 meter antenna, I want to sleep at night knowing the FCC will NOT, and I repeat will NOT come knocking at my door because of violations due to field strength measurements when using an FCC type accepted and approved transmitter like the Rangemaster. I also read a University installed one 80 feet high and claims they get out about 10 miles. Now my conclusion is this, since there are no height requirements on mounting the Rangemaster, you may put it as high as you want as long as you can get to the tuning and broadcast as far as possible. Now as far as your grounding, using a 6 inch grounding cable to attach to your tower and the rest is RF nature to whereever the signal may go. Any comments on this without any technical explaination?
Hi,
You wrote: "Now as far as your grounding, using a 6 inch grounding cable to attach to your tower and the rest is RF nature to whereever the signal may go. Any comments on this without any technical explaination?".
It is just this "RF nature" that caused the FCC to limit the total antenna, transmission line, and ground to 3 meters because they all radiate.
The part 15 rules for AM are written in technical terms. Operation of a transmitter requires at least a basic understanding of technical theory (modulation for example). How do you plan to "tune" your transmitter to 100 mW. without technical understanding? That being said, I will minimize the tech talk here.
FCC type acceptance or certification means the item met their criterion under certain defined test conditions in a laboratory. It is easy to use a certified device and be in violation of the rules.
The choice is yours concerning what risk you are willing to assume by using your own interpretation of ground length. In my previous posts I believe I stated a valid engineering opinion on this. If you mount the Rangemaster on the ground you will not be at risk. If you elevate it you will be at risk.
Neil
I fully understand the concept of RF in AM Transmissions. The only questionable interest is the range people are getting with the Rangemaster of several miles. Does this mean THEY are at risk too? Is this a violation? Read the ad on the Rangemaster. Remember the Hamilton Rangemaster advertises unlimited range and unlimited height for mounting the transmitter and tuning for 100 milliwatt/3 meter antenna.
Hi,
Please see my reply to your most recent post regarding this.
Also, keep in mind that since the Rangemaster is FCC certified they have met the technical requirements for a legal product. They most likely will not be held responsible for illegal use by their customers. No reasonable person would hold an automobile manufacturer liable because a customer gets a speeding ticket in one of their cars. The responsibility for legal use of the Rangemaster is yours. The Rangemaster certification gives you assurance that their unit meets the technical restrictions but it is beyond their control if your installation exceeds the antenna or ground requirements.
You are wise in asking these questions because you care about the law. I hope I and others here can help you.
Neil
First, I have been a long time licensed broadcast engineer and Extra class ham operator. I mention this because I don't want to even be perceived as crossing the line. I recommend you call Keith Hamilton and ask him your heartfelt questions. I find him to be honest and forthcoming. Go to his website, get the number and call him. He has been very nice to me and has answered, candidly, all of my questions. If he does not know an answer, he will tell you. He has offered to reasearch answers for me and been a very wise resource in my growth as a Part 15 broadcaster.
Just because I have been a professional broadcaster and teacher of radio theory does NOT make me an expert. Part 15 is different. Getting information from people who have dealt with the FCC directly for many years in Part 15 broadcasting are a true resource to us. Use them.