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FM Transmitter Range

Topics of general interest that just don't fit anywhere else.
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SolarMax
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Re: FM Transmitter Range

Post by SolarMax » Wed Nov 30, 2022 9:38 am

audiophile wrote:
Wed Nov 30, 2022 6:46 am
Deleted User 15905 wrote:
Tue Nov 29, 2022 5:42 pm
I’m just curious as to how much radiation this 1000 watt transmitter radiates, is there a reason for concern to the exposure. It is coming from China, so does this unit comply with U.S. tech standards? Just wondering.
Who knows.

It states certification for low power device (part 15) BUT it's for a completely different model!
The Amazon listing shows an FCC certification document. Someone who didn't know better (Amazon shopper) might take this as a license that it's OK to just use it out of the box as a broadcasting station at full power. Nowhere in the listing are any licensing requirements mentioned. It's just like the listings for Part 97 rated Amateur Radio gear, which usually shows them as "HAM, CB, Business" radios.
If we're lucky, they'll get connected at full TPO to some sort of improper antenna and blow the finals.



bmw
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Re: FM Transmitter Range

Post by bmw » Wed Nov 30, 2022 8:12 pm

The best option for expanded coverage without going crazy is to buy a CCrane FM Transmitter (version 2) and replace its antenna with a 30-inch or longer telescoping antenna, set that antenna length to 1/4 wavelength the frequency you're transmitting on, and there's one internal adjustment (a small tuning pot) you can adjust to increase the transmit power. Unit runs on 3v and fully modded, mine was able to get out about half a mile with city-grade coverage for probably 800 feet or so.



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TC Talks
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Re: FM Transmitter Range

Post by TC Talks » Wed Nov 30, 2022 9:17 pm



“The more you can increase fear of drugs, crime, welfare mothers, immigrants and aliens, the more you control all of the people.”
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Ben Zonia
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Re: FM Transmitter Range

Post by Ben Zonia » Wed Nov 30, 2022 9:33 pm

bmw wrote:
Wed Nov 30, 2022 8:12 pm
The best option for expanded coverage without going crazy is to buy a CCrane FM Transmitter (version 2) and replace its antenna with a 30-inch or longer telescoping antenna, set that antenna length to 1/4 wavelength the frequency you're transmitting on, and there's one internal adjustment (a small tuning pot) you can adjust to increase the transmit power. Unit runs on 3v and fully modded, mine was able to get out about half a mile with city-grade coverage for probably 800 feet or so.
With dipole antenna efficiency at a height that clears nearby obstacles, 10 mW would put a 70 dBu signal out about 800 feet. Still illegal, technically speaking, regardless of the lack of enforcement.


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bmw
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Re: FM Transmitter Range

Post by bmw » Wed Nov 30, 2022 9:49 pm

Ben Zonia wrote:
Wed Nov 30, 2022 9:33 pm
With dipole antenna efficiency at a height that clears nearby obstacles, 10 mW would put a 70 dBu signal out about 800 feet. Still illegal, technically speaking, regardless of the lack of enforcement.
Recommending somebody use an otherwise legal FM transmitter, that runs on 2 AA batteries, by modding it with a larger antenna and somewhat higher power output, on an unused frequency, on a 5 acre property, in rural Michigan, is akin to telling somebody it is ok to drive 36 MPH in a 35 MPH zone.

Now that 1,000w transmitter - that is pure insanity. Even for experimental purposes I wouldn't put a rig with even a fraction of that power output on the air for so much as a minute.



bmw
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Re: FM Transmitter Range

Post by bmw » Wed Nov 30, 2022 9:55 pm

TC Talks wrote:
Wed Nov 30, 2022 9:17 pm
Here one for the same price with more juice...
The C.Crane unit can be had for under $50. I use one around my house that is slightly modded with the larger antenna and and the power output turned up just a tad from its factory setting. Covers my house and most of my yard and that's about it. The sound quality is very, very good. The original model transmitter had some background hiss, but the revision (v2) eliminated most of that.



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HD74
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Re: FM Transmitter Range

Post by HD74 » Thu Dec 01, 2022 2:41 pm

Hogwash!
It is NOT akin to driving 36 in a 35.
When the FCC comes to your door, you will be subject to a warning and possible confiscation.
If you fail to heed the warning, you will face the same fines as someone loosing 100 watts, 1000 watts, whatever.
Do not think for one second that they are not enforcing this.


You're never too old to learn something stupid.

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TC Talks
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Re: FM Transmitter Range

Post by TC Talks » Thu Dec 01, 2022 3:57 pm

HD74 wrote:
Thu Dec 01, 2022 2:41 pm
Hogwash!
It is NOT akin to driving 36 in a 35.
When the FCC comes to your door, you will be subject to a warning and possible confiscation.
If you fail to heed the warning, you will face the same fines as someone loosing 100 watts, 1000 watts, whatever.
Do not think for one second that they are not enforcing this.
Again, cite any instance of this happening of this happening more than 20 miles from a field office. I think the scare tactics are bullshit. I think that people starting pirate stations would become an engineers nightmare but I just don't believe there's much enforcement. Given the satellite and Jesus crap that's being piped into most rural areas I would love to see pirate stations come up and actually serve the community.

https://sites.google.com/site/napirateh ... tory?pli=1


“The more you can increase fear of drugs, crime, welfare mothers, immigrants and aliens, the more you control all of the people.”
― Noam Chomsky

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originalzzmfmjock
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Re: FM Transmitter Range

Post by originalzzmfmjock » Thu Dec 01, 2022 4:47 pm

Yup not akin to driving 36 in a 35. If you are driving at any speed and not paying attention to what you are doing you may very well kill yourself or someone else. In my 70 years on this earth, more than 50 years of it making a living in the communications field, I have never heard of a pirate radio station killing anybody.



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HD74
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Re: FM Transmitter Range

Post by HD74 » Thu Dec 01, 2022 7:20 pm

Sorry, I have personally been involved in two enforcement issues. You? FM is overwhelmed by a local signal. When your audio signal is at 87.7 and some jack*ss lights up a transmitter say 40 miles out, it destroys the far away station. This results in citizen complaints which lead to an enforcement action. Period. Licensed broadcasters will turn your *ss in and you will feel it. When was the last time you were face to face with the FCC?


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originalzzmfmjock
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Re: FM Transmitter Range

Post by originalzzmfmjock » Thu Dec 01, 2022 9:33 pm

When was the last time I was face to face with the FCC. Funny you should ask, here's my story.

Mid 70's living on the southeast side of Grand Rapids in Alger Heights. I put together a 1 watt station and studio in my house. Operated on 92.5 with the call letters of WWKX-FM and the moniker of X-Rock 92. A top 40 station that was on the air several days/nights per week from 1973-1978.

Sunday December 10, 1978, 12:13pm. I'm on the air and my dog starts barking at the door upstairs. I went up to see who it is and there are 2 guys standing on my porch. I answer the door and it's Irby Tallant and Mike Rhine from the Detroit FCC office. They ask if they can come in and look at the station. I figure it's probably in my best interest to cooperate with them. They take a look at the studio in the basement, then I take them up to the transmitter room which was on the 2nd floor. After testing the transmitter for output power (1 watt) we go back downstairs to the studio. They tell me I can play one more song if I want before I will have to turn off the transmitter for good. I decided not to play one more song (but later thought I should have taken them up on it and played the Z. Z. Top song Heard it on the X. It was a song about a pirate radio station). I pulled the plug on the transmitter and as they were leaving told me I had the nicest pirate station they ever had to bust.

What were the consequences of this?
Did they take the transmitter - No (I gave it to a friend of mine)
Did they cancel my FCC license - No
Did I get fined for my actions - No
Did I get any jail time - No
They just told me not to do it anymore and I've been a good boy ever since : )

Strangely enough my path would cross with Mike Rhine again in the mid 90's. I worked for the Grand Rapids Police Departments communications office for 35 years. 1974-2005 and again 2008-2012. We had a guy who built a transmitter and was interfering with police communications channels during critical moments. With the help of MIke and some of our engineers at the police department the guy was located and wound up paying the price that was much steeper than the one I paid for running a 1 watt transmitter on the commercial FM band.

Now as Paul Harvey would say - You know the rest of the story.

It's 44 years later and as I mentioned in an earlier post there are several small powered radio stations operating in the West Michigan area, some running for more than 20 years with no enforcement against them. Nobody seems to care about that stuff anymore. In fact an engineer friend of mine called the FCC within the past couple of years about pirate stations and they told him if the station wasn't causing interference to one of his stations they didn't want to hear his complaint. True Story.



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HD74
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Re: FM Transmitter Range

Post by HD74 » Thu Dec 01, 2022 9:56 pm

Nice story, and I knew them. Since you were running an unlicensed station, what license did you have to lose? Remember, the 70’s are long ago. Your later story confirms what I just stated. I have never had them tell me they weren’t concerned. Interference with emergency communications is now a felony. After the homeland security act that includes licensed broadcast stations, so yes, a felony. Just don’t do this. It’s asking
to have your nose bloodied through your wallet. I have no more to say, if you let me know I’ll come visit you in jail.


You're never too old to learn something stupid.

originalzzmfmjock
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Re: FM Transmitter Range

Post by originalzzmfmjock » Thu Dec 01, 2022 10:13 pm

License was a 3rd class with broadcast endorsement. Back when they had such things.



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HD74
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Re: FM Transmitter Range

Post by HD74 » Thu Dec 01, 2022 10:18 pm

Yep, it authorized you to work under the supervision of a Class 1 with whatever endorsement. Mine was ships radar, now it’s General.


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bmw
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Re: FM Transmitter Range

Post by bmw » Thu Dec 01, 2022 10:41 pm

HD74 wrote:
Thu Dec 01, 2022 2:41 pm
Hogwash!
It is NOT akin to driving 36 in a 35.
When the FCC comes to your door, you will be subject to a warning and possible confiscation.
If you fail to heed the warning, you will face the same fines as someone loosing 100 watts, 1000 watts, whatever.
Do not think for one second that they are not enforcing this.
If you're out in the middle of BFE broadcasting with a slightly modified transmitter that barely covers a 50-acre parcel and has a signal that marginally leaks onto some neighboring dirt roads, who in the world is even going to report you to begin with?



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