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I wonder myself, if the whole point of the ferrite choke is for is lightning arrester or to stop a direct hit to the antenna and fry the transmitter, which would be installed along the ground line in between the transmitter and the ground I can’t see how this would prevent a lightning strike. A million volts or more I would think doesn’t care about a choke between the transmitter and the ground. But just my opinion, I think a deterrent so lightning will target something else would be a good option. A 6 ft metal pole in the ground say 15 ft away from where the transmitter is could give lightning a more appealing target. Something like a thin fence pole you could bang into the ground.
Or if you have a TV antenna/tower nearby grounded would also be good.
Timinbovey has his outside on a 30 ft(I think) pole with no ground but the pole is grounded that the transmitter is on and he has never had it hit in, I think he said 10 years?Wait, I went back to Tim’s post and saw that he has it mounted on the side of the house. Not on a pole so it wouldn’t get hit in that location. Have you thought of something like that?
RE: …The wire between the Ferrite Filter Choke and to whatever we choose to attached to use for a ground, be it a short 3 foot galvanized galvanized pipe driven into the ground, a short copper ground rod, or a cold water pipe, that wire would be dismissed as a part of the radiator, making it in compliance with Rule 15.219 because we are within the three meter or 118 inch rule for the antenna and wire for ground.
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Physics proves that belief to be driven by intuition, rather than science.
A reduced amount of r-f current continues to flow on whatever length of conductor is connected from a practical ferrite choke output to whatever is being used as an r-f ground reference (such as a cold water pipe, ground rod etc).
That r-f current produces e-m wave radiation into space from that entire length of conductor for the same reason it does when it flows along a 104″ conductor attached to the antenna r-f output connector of a transmitter.
Therefore that entire length is part of the radiating length of the antenna system that must be included in the compliant length authorized by FCC Part §15.219(b).
A ferrite choke is an r-f resistor, not an on/off switch.
Hi Rich, and for Mark in Toronto,
There is that human side of me saying “don’t give up” there is a way. I believe we all feel that way.
I agree 100 percent, the Ferrite Filter Choke is not a switch, it is a filter to minimize field strength. I believe that was what Mr. Hamilton designed it for.
I look back to a article written on Wednesday, December 25th, 2019, just before the Covid-19 Pandemic hit the U.S. and Canada, it was a article was written about Ken Cartwright and his (Part 15 KENC) Hamilton Rangemasters in Stayton, Oregon. He put this project together and started in 2007. According to my understanding of the article, one of his transmitters was mounted to a tower, there was 3 meter antenna, but there ground lead attached to a unshielded radiating tower of 40 feet. That’s a huge “No No”, and I ponder if anybody has any sense to understand, this can not be done. I guess it was o.k. to attached the transmitter to the tower, but not the ground lead. My understanding reading the article, according to Mr Nguyen, The FCC Field Agent, the Rangemaster Transmitter could stay mounted on the 40 foot tower, but no ground lead could be attached to the the tower. My understanding is if the transmitter was on a small pole down at ground level, then Mr. Cartwright could use ground lead as long as the antenna and ground lead did not exceed 3 meters.
http://part15lab.blogspot.com/2019/12/a-look-back-at-kenc-1620-am.html?m=1
I found another picture where a gentleman was testing a Chez Procaster he just gotten at the time. He said in his testing this statement:
“I found a 3 foot piece of galvanized fence post and stuck it in a hole in the patio that had been used for a clothes line pole at one time. The transmitter mounts with two U-bolts that just managed to fit around the pipe and hold it snugly. AM radio needs a good ground for the most range, and the wires underneath are an attempt at a simple ground, connecting the transmitter’s ground bolt to anything metal in the area. The antenna is 3 pieces of aluminum that fit inside each other, think of a portable radio with a rod antenna that pulls up, just in giant size. Once extended, tightening the hose clamps keeps the sections from sliding back down again. This setup is temporary, I just wanted to get something on the air for testing. The location is bad for getting a signal out with the short antenna.”
I wonder what he done is legal for permanent use, could using a Ferrite Filter Choke at the ground lead under the Chez Procaster Box be acceptable?
I’m sure both of you have read these articles.
Finally, I was thinking instead of using my Procaster at my house, I would go to a small town, no community radio station, a town that has a population of 1,000 people or less, a small town square, talk to a business owner that would let me mount the Procaster on top of the building on a pole. Only problem, can’t use a ground lead in that case, at least I’m understanding this for Rich that wouldn’t work well. I would think it would be legal, however.
Yes there is always a way!
As for the interesting story of Ken Cartwright he had to be aware of part 15-219.
I feel for him though and although there is no field strength if you have a signal that is extraordinary it leads them to look closer to see what else they can find.Tim has his 30 ft up on the side of the house, no ground and gets a mile or more with a typical radio as I assume that’s what a solid signal means.
There is always a way and I just thought of this….may not be right but an idea since the FCC it seems is most concerned with a ground lead radiating rather than being more than a certain length.
What about using a *shielded*ground lead from your location say 30 ft up?
A shielded ground lead?… a top of the line quality coax cable as a ground lead. From your transmitter to your underground set up like a stake or radials.
You would be using center conductor as the actual lead and the shield would prevent radiation. The center conductor at ground level would directly connect to your stake or radials underground.
It’s shielded so it would not radiate. So if you mount the Procaster/Rangmaster on a pole but have the coax to ground not the metal tower it would be not radiating and you *may* get away with that since all I hear is the concern of a ground lead radiating. So, stop it from radiating.
But that still won’t solve the lightning issue. Can you contact the FCC? I think you said you know someone there? Ask about my idea.
I am not suggesting in any way to violate the rule….just suggesting .. “what if the ground lead doesn’t radiate?”On the situation with Ken Cartwright, seems from what I read the FCC Field Agent, Mr. Nguyen was willing to help Ken make his operation legal, in fact, in one location where Ken Cartwright had a Hamilton Rangemaster in use, I take it Ken was using a metal roof for a group lead or attached the ground lead of the Hamilton Rangemaster to the metal roof and Mr. Nguyen said that was o.k. Tell me if I read that wrong or right, but that’s what I think the article said as Ken Cartwright was using multiple transmitters, which I don’t want to do. That’s expensive.
There is no metal around my house. My home was built in 1977, the typical concrete blocks at the bottom, with lumber.
A “shielded” ground lead. That is a idea. I’m thinking you are saying we could use RG 58 Cable, like standard cable we use for Cable TV.
We would use the center conductor as the ground lead to the ground. The sheild and the heavy insulation of the cable cut the ground wire radiating.
Here is one thing Mark, my opinion only, we can sit here with software, use computer models and tables saying this is what will happen, but until we go out and actually conduct test in different areas of the United States and Canada, in my opinion, we can not hold these “software model theories” as the gospel truth.
My opinions is we’ve learned that in such cases in the medical field, using that field for a example.
My experience with the FCC is this, when we take a FIM, do actual field strength readings, we present them with this data, then their engineering department decides if they will give us a “CP” or Construction Permit to build the proposed site, then, we must go back, prove it meets the standards with the FIM before they will issue a permit or license, of course.
One Engineer out in the Western part of the United States pointed out in a You Tube Video the Part 15 Rules haven’t been updated since 1991, and that could of been Part 15 rules that has nothing to do with this “hobby broadcasting”. It deals with interference from appliances, computers, etc.
He also said that they (The FCC) wanted to tighten the Part 15 Radio Rules to discourage Schools (College and High School) thinking they could just build some low power “classroom or club” radio station and breaking Government Laws.
Tonight, as I am replying to you, we have a thunderstorm moving through the area. The TV Stations in my market going crazy scaring people as normal. Our weather her in the South Eastern portion of the United States is not like what Tim’s is up near the United States/Canadian Border. Gerry at Procaster said that. Gerry has been in the State of Florida and we discussed how the ground is nothing but sand, and the ground conductivity is very low.
RE:
… What about using a *shielded*ground lead from your location say 30 ft up?
A shielded ground lead? … You would be using center conductor as the actual lead and the shield would prevent radiation. The center conductor at ground level would directly connect to your stake or radials underground. …
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Unfortunately, while both conductors of a coaxial cable used as proposed above will have approximately the same electrical characteristics along and at both ends of it for direct current, that will not be true for alternating current (including radio frequencies).
R-F current produced by the transmitter is referenced to its internal chassis common path, and it will travel along whatever conductor(s) are connected to that chassis — which will radiate e-m waves into space.
Hi Rich,
In this drawing you posted, it appears this this Dipole is to be 10 meters above the ground (the soil). It hit me this morning, could we could this down to 5 meters, which breaks it down to 16.4 feet. Or perhaps you can run in your software in theroy, we could go down a bit more to 4 meters, that’s 13 feet, 1.48 inches. This clears the eave of my house. I live in a one story house. A thought Rich, coming from a Ferrite Filter Choke under the transmitter, going down the 13 feet, 1.48 inch meter pole, would a 6 gage insulated wire be sufficient to ground?
Looking at your drawing below, working from that, let’s say we put a Ferrite Ground Choke there, attached to the box of the Chez Procaster or a Hamilton Rangemaster, what does that give us?
This is just a idea (thought). What I would like to do once we come up with a solution, I want to show it to my Consultant Engineer, who is “kinda of also” a FCC Attorney. I also retained my FCC Attorney in Washington if I decide to come out of retirement to buy a small AM Station.
I’m reaching 60 years old, and my doctor told me if I stay busy with my mind and what I can do physically, I live longer than sitting around watching the News on TV, worrying about which way our government is going in policy.
I’ll be upfront, I am a Conservative. When it comes to any law, we should follow it, but only make modifications if we all can agree it will be in the best interest. I have another friend of mine that lives near by in the next county. When he worked at the local radio station in his county, he told me he was a self student of yours and followed your ideas and theories. I told him that was bring smart. I was running my 1 KW commercial AM Station then.
The idea you presented in 2020 was great, but as I said, I have a wife who won’t let me tear up the backyard. I told her, we’ll then, find us a house outside this small town. I like very small towns, smaller than the one we are living in now.
Your idea published in Radio World, June 29th, 2020 was a great idea, but my problem is where we live, my wife has declared to me, “You are not putting that Transmitter out in the middle of the yard and dig the yard up either”. We have a fence around the backyard, our small Yorkie Dog that likes to chase squirrels up the trees and rabbits would not be able to get near the transmitter. I’d have a small wooden fence up where the dog couldn’t get to it, and I didn’t think she would bother it anyhow. That dog of mine loves to hunt.
RE: .. I live in a one story house. A thought Rich, coming from a Ferrite Filter Choke under the transmitter, going down the 13 feet, 1.48 inch meter pole, would a 6 gage insulated wire be sufficient to ground?
Not legally, because r-f ground potential does not exist along the exposed length of such a wire, regardless of its gauge (whether insulated or not). The wire will be a radiating section of your antenna system. With the radiating conductor attached to the r-f output connector of the transmitter, this antenna system is almost certain to exceed the 3m length permitted by FCC §15.219(b).
… Looking at your drawing below, working from that, let’s say we put a Ferrite Ground Choke there, attached to the box of the Chez Procaster or a Hamilton Rangemaster, what does that give us?
A monopole transmit system with unnecessary loss (the choke) in its connection to r-f ground reference. The power lost in that choke will not be radiated.
Rich,
Let me ask you this a simple question, if we or another party filled for a modification or amendment to 15.219, allowing the ground lead to exceed 3 meters (not the antenna) would you oppose it?
RE: … if we or another party filled for a modification or amendment to 15.219, allowing the ground lead to exceed 3 meters (not the antenna) would you oppose it?
Not if the claims of the party or parties filing for the change(s) in Part 15 Rules are based on accurate, scientific principles with respect to the operation and performance of those systems.
Probably not even then, because the FCC will evaluate this when such changes are formally proposed to them.
Hi Rich,
I know within the past five years, at least during the Obama and Trump Administration, the top Commissioners have been approached about it. They don’t know anything.
It would take a FCC Attorney with studies done to present to the Audio Division’s Engineering Staff. I have met one of them. I know Mark hates me to bring up “politics”, but in the United States, our system allows the opposition to file against it, hence the NAB (National Association of Broadcasters), I was once a member.
One of my points, the AM (MW) Band is in a very sharp decline of listenership, as the youth of the United States has not just gone to FM, but now the Internet, Online Live Streaming, Podcast and Downloading. I’m near 60, my generation barley remembers listening to AM.
Let’s keep in mind, the number of AM Licensees has dropped, stations going dark, turning in the license. Now, I hear there is a proposal from the NAB to the FCC to allow AM Licensees that have FM Translators that simulcast the AM’s programming, to turn in the license of the AM Station and make the FM Translator the permanent station. This would bring down the number of AM Stations in the Country dramatically.
At that time, more Part 15 AM or LPAMs could be a possibility, as long as we don’t allow the AM Band to become what it was.
I’m hearing around the U.K., the Netherlands, and a countries creating a LPAM Service, allowing the broadcaster to use up to one watt. I hear their governments have dropped high power AM operations to allow this.
At least in the United States, we probably could only do this from on the frequencies of 1610-1700 KHz in the U.S. for now. Many of the Commercial Stations in that part if the band have FM Translators now, so there is a good possibility those Licensees would want to turn in the AM License. In the end, this would probably leave just our licensees of the 50 KW, Class A Stations, which are worth something to corporations like iHeart, Cumulus, and Audacy.
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