FM Transmitter

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

  1. Punker X

    Punker X Moderator Moderator Subscriber

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  2. I LIKE MUSIC

    I LIKE MUSIC Super Member

    The pictures below shows how the set the transmit frequency. This unit uses hexadecimal coding to set the transmitter frequency.

    upload_2018-6-28_9-23-11.png


    Note that in the chart below there are 2 setting for each frequency. One for stereo (S) and one for mono (M). If it were to be used for music at your pool side or deck and range was an issue, mono would likely give a longer range and possibly a less noisy signal.

    upload_2018-6-28_9-25-7.png


    This device is professional grade and typically used for wireless assistive listening applications. No bells and whistles, just set it and forget it (no I am not Ron Popiel).

    Note this company also makes devices that are used for the same application and are used in the ISM band of 72 MHz to 75MHz.
     
    Last edited: Jun 28, 2018
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  3. Bob@FM

    Bob@FM Active Member

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    My apologies for posting that link, I think it may be a scam, please do not order from this company !

    The old saying likely applies here - "if it looks too good to be true, it probably is".
     
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  4. robgmn

    robgmn Super Member

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    An FM transmitter would be good.

    There are tons out there from the "WholeHouse FM Transmitter" (wayyy overpriced) to BlackBox (wayyyy overpiced) to t he ones you can get on the 'bay or from sites like FocalPrice, AliExpress, etc.

    If you find one you are interested in, Google it and check YouTube. Someone has probably tested/reviewed it, and you can get an idea of what you may be buying.
    YouTube example below.

    BTW - I've been running a TX fed by a computer for about 10 years now. I started with a transmitter that was made to plug into a car lighter and modified it for better range.
    I then graduated to a home-built Ramsey transmitter, then to an overpriced BlackBox (other cheaper options were not available at the time) that feeds an antenna up in my attic.

    The PC runs JRiver and currently has multiple playlists that are set to play at different times of day. I've done some EQ work to make it sound more like a radio station, and have even added bumpers that play at random to break things up a bit (sometimes you just need to hear a "commercial" and not non-stop music).

    I also stream the music directly from the PC to my Android phone/s via Muzecast anywhere that has internet access .

     
    Last edited: Jun 28, 2018
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  5. I LIKE MUSIC

    I LIKE MUSIC Super Member

    Thanks for the video.


    It is interesting that he mentions that it uses the BA1415F transmitter chip. This is the same chip that is used in the Ramsey FM100B.

    At the end of the video he mentions changing the pre-emphisis. It appears that it 50 microseconds, instead of 75 microseconds.

    Pre-emphisis is an EQ curve that is applied to the audio prior to transmission. A receiver/tuner will have the inverse curve. For the best fidelity, the curves should match, although it may not likely be a big deal in this type of application.

    That is likely the same transmitter that musichal tried.
     
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  6. robgmn

    robgmn Super Member

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    One of the many reasons the overpriced transmitters may have some value :)
     

     

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  7. Bob@FM

    Bob@FM Active Member

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    My Landmark FM350 also uses the Rohm BH1415F. I think they previously had a BA1404, but not 100% sure there ever was a BA1415F. I think I've seen confusion around this before as well...

    Bottom line, most of the better older units were based on the BH1415F, and the implementation was important. But done well, there may not be substantial differences in audio FM performance from one model to another.
    The Ramsey does include features that are very important if you are broadcasting live music or speech - the limiter/compressor.
    But for digital sources, that are already limited, and players more or less produced to meet a standard output level, that may not be as important.
     
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  8. DustyOldPile

    DustyOldPile Vinyl Goddess

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    The Ramsay may work extremely well, but boy... that faceplate is butt ugly! Straight out of 1975.
     
  9. 39cross

    39cross AK Subscriber Subscriber

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    Interesting stuff they have, I checked out the link. I don't see an FM350 transmitter, just a receiver, maybe that's discontinued?
    What looks interesting to me is the Landmark S100 Transmitter, it covers a wider frequency range than conventional FM OTA broadcasting; you could put it to use with a Japanese market tuner if you somehow ended up with one, for your home broadcasts. I see these pop up on eBay as the poor orphans of the tuner world. Not that anyone would do this...just a thought.
     
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  10. I LIKE MUSIC

    I LIKE MUSIC Super Member

    Thanks for the correction, my health and medication muddles my mind and sometimes causes me issues and I miss things.

    Way back in the day before cheap LCD displays and programmable controllers, it was not as cheap and easy to build a frequency programmable FM transmitter to cover the entire FM broadcast band.

    Back in the day, they typical implementation of the BA1404 used a variable capacitor or inductor to set the transmit frequency. BA1404

    There may have been an implementation that used a programmable PLL for frequency determination.

    I built my first FM transmitter using vacuum tube. It used a variable frequency oscillator and a frequency multiplier chain.

    It was not stable, the output was not clean and the audio was poor, but it did make sound on a receiver, but what more could a farm boy with out a father want?

    My next version used a crystal controlled RF oscillator and frequency multiplication chain. It had much improved audio with real pre-emphisis and much improved RF filtering on the output. Still DIY grade, but it was quite listenable when fed from a 1951 Webcor reel to reel.

    It was given to me as a present. Wow, it was bi-directional mono (although not automatic) play and record.

    BTW, I am not old...:no::eek:
     
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  11. musichal

    musichal poet emeritus Subscriber

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    Breaking News: Strange Development with the TiVDIO Transmitter

    Just got a phone call from Angela, a young lady with a strong Asian accent, who would tell me later in the call that she was calling from China. Our conversation went essentially as follows.

    "Is this person who return the FM transmitter to Amazon?"

    "Yes."

    "Well, we like to send replacement..."

    "That won't be necessary. I've already returned it for full credit, and decided against the purchase."

    "Yes. I know you return for credit, but we like to send replacement."

    "I can understand that, but I tried out the transmitter, and it was too noisy for my purpose, so why don't we just leave it like it is?"

    "But we think you have one that defective, and like to send replacement you try."

    "Ma'am, I'm sorry, but I decided I didn't want to buy it."

    "Did Amazon give you money back? You have refund."

    "I think they probably have, not entirely certain, but they issued a credit and said it should show up on my credit card in two or three days."

    "So you receive refund, and now we send replacement you try."

    "While I admire your persistence, I simply don't want to buy another one."

    "I not understand all, but we send you replacement, you try, and if happy you change review - you gave us two stars."

    "Ma'am, I just don't want to buy one anymore."

    "No, you have refund, we no ask money."

    "Are you saying you want to send me one free - no charge, no pay - just to try out?"

    "Uh... but we want you change review."

    "I think we better just leave things as they are, because I'm not sure we are communicating clearly."

    "Yes, but we send you new transmitter, if make you happy you change review."

    "But I decided I don't want one."

    "You try new one? You no pay. If you like, you change review."

    "Ma'am, I don't think this is a good idea. I won't change my review in exchange for a free transmitter."

    "No. You change if like transmitter. We think you like."

    "I don't want to pay to ship it back, either. Understand. No pay for transmitter, no pay shipping, no pay anything.."

    "No, no. No pay anything. You keep transmitter. You change review if make you happy."

    "I still think this is a bad idea. I will not promise a good review. If you want to send a free one for me to give a second shot, okay, but if you charge me, I will complain to Amazon and will lower your transmitter to one star. Do you understand?"

    "Yes. We send you transmitter. No pay. It make you happy, you change review. You keep transmitter, no pay. If no make you happy you talk me in emails and we try make work good."

    "I can make you no promises that you will like what I write in review. Understand?"

    "Yes, you watch email and I send message now."

    "What is your name, and where are you calling from?"

    "My name Angela, I call in China where is business."

    So I gave her the email address and she sent a hi just to confirm communication. By this time next week some Chinese scammer will probably be writing nonsense at Audio Zen under the name musichal while emptying our bank accounts. LOL. If I hadn't read so many remarks about Angela by Amazon user reviewers, about how nice she is, I wouldn't have agreed to this deal.

    I think she had as much trouble with my Deep Southern accent (Mississippi, ya'll) as I did with her Asian one, and the conversation went much longer than this, as I am always suspicious when someone wants to give me something, though the circumstance seldom arises. I refused more times than indicated in the above paraphrase, but she was patient, persistent and so nice she wore me down. Looks like there may be a Round Two upcoming.
     
    Last edited: Jun 29, 2018
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  12. I LIKE MUSIC

    I LIKE MUSIC Super Member

    Wow!

    That is some story. I hope that it all works out.

    Possibly after all of the speculation, you did just have a defective unit.

    I certainly hope not.
     
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  13. 39cross

    39cross AK Subscriber Subscriber

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    Round 1 goes to Angela :)
    I am going to bet it sounds the same, just to make in interesting. But you never know, maybe they will cook you up a personalized super unit.
     
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  14. jlovda

    jlovda Things I loved from the 60's and 70's Subscriber

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    Listen to The Who Sell Out album from about 1967. See my avatar. The album sounds like a pirate radio station in Britain during that time period. The Who tracks are interspersed with commercials for Odorono, Heinz Baked Beans, Rotosound Guitar Strings, etc. Fun to listen to. Search "the who sell out commercials" on YouTube.
     
    Last edited: Jun 30, 2018
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  15. Bill Ferris

    Bill Ferris Super Member

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    Mercy Sakes Alive musichal !!
    I would be interested in hearing about your experience with the replacement unit(FM XMTR) after you run it through it`s paces..

    Very interesting development..

    Good luck..
    Kind regards, OKB.
     
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  16. imral3

    imral3 Super Member

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    This was such the entertaining read - absolutely loved it!!! I'm looking forward to round two and maybe listening to The Whale, WHAL, radio. But, me thinks the 1,701 miles separating us will hinder that a bit.
     
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  17. musichal

    musichal poet emeritus Subscriber

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    Haven't heard anything else from Angela, but I believe her purpose in sending me a hello e-mail was to establish the communication link for troubleshooting after the transmitter arrives, if indeed one is coming. From what has been posted about her by other buyers, I figure one will show up.

    A five-foot round of sheet-metal for mounting the antenna is not anything I have lying around nor would I have a place to put it if I did. Keeping an eye out for something a bit smaller, but larger than the pizza pan I tried. Also, I'm considering where best to place it, and the attic above the garage seems my best option for several reasons including that it offers easy access - the most important factor for enrolling Christine's aid.

    Hmmm... part of our remodeling around here a couple years back included one of those large stainless steel vent-hoods over the stove in the kitchen. It came with a pretty large section of stainless extension for use with higher ceilings, which we did not need. Where did that get off to? I'll have to ask Christine - it may well be already in place, and wouldn't that be convenient?

    Also, I LIKE SOUND, would any of those ferrite chokes I bought on your recommendation for the dipole build (pending) be of use here? I think I bought 15 of them. Satisfyingly heavy little buggers, BTW.

    Just starting to think about Round 2.
     
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  18. imral3

    imral3 Super Member

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    You got me wanting to play!!
     
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  19. Watthour

    Watthour Electron Rancher - JS3600

    Very similar here. Playlists on a PC run until I stop them. There are station I.D. breaks scattered through the playlists.

    The down-side is that the transmitter screws with my TV reception, so I have to be careful of when it is on and a what output level. It also blanks out my overhead door operator so I actually have to get out of the vehicle and right next to the garage to remotely open the door. RF is RF.
     
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  20. musichal

    musichal poet emeritus Subscriber

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    Dang it. We use our garage door opener a lot. If I put the antenna in the attic above my garage and it kills my remote function, then I'll have to relocate it. One more thing to check. And placement is beginning to look like a big hurdle - if the Xmitter does what I want.

    However, another issue is that the intended antenna location puts the transmitter itself in my unheated, uncooled garage. Good for fan noise, but... With high summertime ambient heat... could overheat the Xmitter. Even at its lowest setting? IDK. There'a always something - make that somethings. There's always somethings.
     
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