FM Transmitter

Discussion in 'Tuners' started by musichal, Jun 18, 2018.

  1. musichal

    musichal poet emeritus Subscriber

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    Inserted between antenna and transmitter, I guess?

    I see it attenuates from 15w to 1.5w. Does it then attenuate 1.9w to 0.19w? The transmitter offers output adjustment in 1.9 increments. 3.8 becomes 0.38? 5.7, 0.57? & etc?

    If so, that could be a very helpful circuit to dial in just the right low-power setting needed.
     

     

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  2. I LIKE MUSIC

    I LIKE MUSIC Super Member

    Yes, that is correct.

    Yes, that is correct.

    And you can built the attenuator for more attenuation (less power to the antenna) if you so desire.
     
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  3. Bob@FM

    Bob@FM Active Member

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    here's the web page for that power calculator
    https://a29.veron.nl/hams/pa1b/pa1b-power-attenuator-calculator/

    Note one thing that most of us know about resistor power ratings -
    As previous, also be careful to NOT use typical cement type or wire wound resistors, who have significant inductance at RF frequencies. Carbon or specifically "non-inductive" resistors are OK.
     
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  4. musichal

    musichal poet emeritus Subscriber

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    Be danged if the transmitter didn't just show up on the doorstep. I'll be trying it out again later, and let you know how it goes... maybe ask some questions. So the stage is set for Round 2.
     
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  5. Bill Ferris

    Bill Ferris Super Member

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    :thumbsup:
     
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  6. RickB

    RickB On the Road to Find Out

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    :lurk:

    .
     
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  7. I LIKE MUSIC

    I LIKE MUSIC Super Member

    Musichal, you might be interested in the article linked in this thread.

    From the article.

    Ajit Pai chairman of the F.C.C., promised to “take aggressive action” to stamp out pirates. In early May, the Preventing Illegal Radio Abuse Through Enforcement, or PIRATE, Act was introduced in Congress; it would increase fines from a maximum of a hundred and forty-four thousand dollars to two million dollars.

    It is interesting that this bill would give state and local governments the ability to impose civil and criminal penalties, although the FCC would be the last word in determining piracy.


    We will be passing the hat for you.:eek::D
     
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  8. dewdude

    dewdude I fix stuff.

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    So let me say this....regardless of how much you attenuate the output and comply with the field level for Part 15.....that transmitter is illegal.

    In a finished form...the device MUST be certified for Part 15 compliance. That will NEVER happen with this device due to the fact it has an antenna jack and external antenna. For that reason alone....any certification it has is likely counterfeit and it would never get certified.

    This is why you'll see "kits" for transmitters more than you'll see a ready to go product. You don't need certification to legally sell it...that would be up to the builder to ensure compliance. But if you sell "part 15" transmitters without full certification you're breaking the law.

    Now the confusing thing. ItsI not illegal to posess this thing...mere poesssion is ok. That's why these things are kind of a grey area. From the seller's aspect I'm not 100% sure what the rules are. With the FCC it's a lot about literal marketing. Market it as a low power transmitter itsi fine...sell it to normal people as a legal device and they have problems.

    So what's the danger in using this? Technically it's a violation of federal law. Don't forget FCC regulations are part of US Code. But the FCC is mostly enforcement...and like on an empty desert road...if there's no one to enforce how will anyone know. They don't go looking like some think...they mostly act on complaints. Most of the pirates spoken about in the previous post are the people putting serious power on the FM band...operating as an unlicensed wide coverage station...and usually wind up interfering with a license holder. It's from complaints they take action...and it's a difficult process.

    If they were to send you a NOV (notice of violation) over it....they usually give you a chance to rectify the problem before they start additional proceedings.

    I still wouldnt have such a thing in my house.
     
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  9. musichal

    musichal poet emeritus Subscriber

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    Call me an anarchist. But I'm not. However, there are several laws that I don't agree with, and think are past due needing changed but I'll not stray into politics here. Fact is, I don't give a damn that the device is illegal - or rather, can be used illegally. My intended use is not apt to result in any complaints, but if I did receive such a notification, I certainly would change what I was doing. My target piracy realm is a very limited one. If this new one sounds no better than the previous, I won't be using it at all. Technically (your modifier), how many laws per day does an average fellow break, I wonder?
     
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  10. dewdude

    dewdude I fix stuff.

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    "In Jersey anything is legal as long as you don't get caught."

    Same is true for a lot of stuff.

    Me 4 years ago would have been all "screw it! let's go till we get caught". These days...due to the fact I have FCC issued radio licenses...I put more on the line. They show no mercy to a licensed individual caught doing pirate activities.
     
  11. Retrovert

    Retrovert AK Subscriber Subscriber

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    Hmmm. You ever live in Jersey? Because only someone in Jersey could truly appreciate that logic. (NB: I grew up in NJ, but was eventually deemed ready to rejoin society and allowed to emmigrate.)

    The FCC, furthermore, has a policy that anyone found responsible for operating an illegal transmitter cannot obtain an amateur radio license.

    Hams can triangulate an illegal transmitter faster than you can say "Radio Direction Finding".
     
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  12. evsentry3

    evsentry3 Well-Known Member

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    It's fun when somebody in my area gets one of those transmitters. Takes minutes to find them and report it.

    These days, there is so many low power and translator stations crowding the band that there really is no place on the dial that an illegal isn't stepping on somebody's toes. And often several toes. I can't imagine in more congested areas how stacked up it's getting. And here is the bad thing...receivers that can separate out the signals are getting fewer and fewer. And yet we have more and more signals being jammed in. That's why these "I didn't mean to cause anybody any harm" signals are such a problem. Why would those that enjoy the listening want to cause further harm?

    It's also easy to tell when it's one of those really junky units as not only is the spectrum it transmits is bad, but as experience already in this thread, the audio of generally pretty bad too. When you try to condense a whole big boxed expensive unit down to a single chip, something...a lot actually...has to give.

    EV3
     
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  13. musichal

    musichal poet emeritus Subscriber

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    Fun, huh?

    That's a thread-killer.
     
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  14. barefootbrew

    barefootbrew AK Subscriber Subscriber

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    That's a bummer.....
     
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  15. Harvestor

    Harvestor Super Member

    Movie:
    Pump up the volume
    With Christian Slater

    If you have a message that just must get out past all the censorship like "THE CHAIR IS AGAINST THE WALL ------JOHN HAS A LONG MUSTACHE----" to Quote another movie
    ..
    Then keep moving like Mr Slater
     
  16. audiotemp

    audiotemp Well-Known Member

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    The sound quality of even a single-chip FM transmitter can be quite decent. At least some of the little devices that are (or, at this point perhaps, were) sold to play a portable music player through a car FM radio have SQ that is quite acceptible...as long as they are not over-modulated.
     
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