FM Transmitter

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

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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.

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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.
 
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Is this a reputable site? Nice price. Be nice to have a backup or compare against the Ramsey FM-100B

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".
 
What would be a good transmitter for taking an FM stream from a PC and transmitting it to tuners in various rooms in the house?
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 .

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

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.
 
The Ramsey 100B has the looks to make you think your a big time broadcaster...:D:beerchug:

It even says "professional" right on the front. To be clear, it has a lot of very satisfied users.

View attachment 1221029

The C. Crane transmitter receives mixed reviews. Quite a few complaints about range, but this it be expected right out of the box. It is interesting that it uses the Silicon Labs digital FM transmitter chip.

This could be an issue for the analog purist.

This chips coverts the analog audio input to digital audio and does all of the audio processing in the digital domain (limiting, audio level, pre-emphisis and so on). I make no promises that the current production unit is RF output power adjustable.

Here is block diagram of the Silicone Labs FM transmitter IC. Note that it even as an input for direct digital audio, although it is not available with the C. Crane transmitter.

View attachment 1221019

Here is a PDF with the data on the Silicone Labs FM transmitter for those (likely only a very view) that are interested in this kind of "stuff". IIRC the C. Crane transmitter used a buffer RF output stage (I believe it was a Maxim RF chip).

The Whole House transmitter seems to offer a good bang for the buck and seems to get reasonably good reviews.

The Ramsey FM100B, again IIRC, uses the BA1415F. It is a much older IC and is analog audio all the way, and some what less sophisticated. That does not mean that it does not work well.




He likely used to to boost the output of what ever transmitter that he was using. A TV antenna amplifier is just that an amplifier, not a transmitter.

All though back in the day when I had my shop, I had to track down some antenna amplifiers that had failed and started to self oscillate, producing a rather dirty signal "going to" the antenna, and causing no end to over the air TV reception issues.

BTW, musichal, you know what they say, in for a penny, in for a pound. You might as well go whole hog as they say and go with some top of the line equipment.

The Ramsay may work extremely well, but boy... that faceplate is butt ugly! Straight out of 1975.
 
My Landmark FM350 also uses the Rohm BH1415F....
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.
 
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:
 

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.
 
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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.

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.

I certainly hope not.
 
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.
 
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 .

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.
 
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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.

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.
 
It lives! Testing it out on the dining room table. Here are my instructions to get it up and going, in American English:

Quickly scan the 4-page "manual" the day before connecting.
Tear open box and remove the Xmitter.
Do not plug in the power cable until you have connected the antenna, ever.
Screw the antenna onto the back of the unit. Important to do this first, before connecting anything else.
Grab the heaviest package and open it, wondering what it is.
Realize that it is an antenna stand.
Unscrew the antenna from the back of the Xmitter and screw it onto the stand.
Screw the antenna cable from the stand into the back of the Xmitter.

Plug the provided 3.5mm to 3.5mm cable to your source, or use RCA to 3.5mm cable (not provided - that's okay, you've got about forty somewhere) if necessary. I was testing with my Zune, so the provided cable made it unnecessary for me to spend an hour finding one among the twenty or so I have, carefully rat-nested with many other various cables. The 3.5mm end remaining plugs into the front of the Xmitter on the left side, Audio-In. The other, on the right, is clearly Mic-In so not even I got that wrong.

Plug the power cable into the back of the Xmitter before plugging the other end to 110 - get the order right here or you might see sparks warns the seller (in-line power supply doesn't block other outlets on your already-overloaded power strip - yay!).
Plug the power supply into 110v outlet.

Press Power button.
After a few seconds, when the alarm starts it's piercing beep, beep, beep, push all the buttons at random, watching the display.
When anxiety reaches its peak, with your wife shouting at you to turn off the alarm, shut down the power and find the manual and your lighted magnifying glass.
As you read, realize that pushing the antenna across the table was likely a bad idea, and re-locate it further away from Xmitter, at the end of its fifteen-foot tether, realizing now why they included the stand with 15' cable.

Press power button to turn back on (standby/transmit are press and hold).
With no alarm now disconcerting you, scroll through the short, simple menu with quick-presses of the Power button.
When FWD (followed by bars) begins flashing, stop quick-pressing the Power button, unless you pass it up, then keep pressing until it comes around again (very quickly) quicker than you thought it would so keep quick-pressing until you inadvertently stop with FWD flashing and all bars lit up.
Press down-arrow button until no bars are lit up, which is the 1.9 watt setting - the unit's lowest.
Refer to manual again for which icon lets you adjust Xmission frequency and set that with menu and up/down arrows to your predetermined broadcast frequency. In my case 97.7, determined using Radio Locator.

https://radio-locator.com/cgi-bin/locate?select=city&city=73071&state=&x=0&y=0

Check chart in manual for the precise antenna extension in inches for your frequency, then eye-ball it like I did 'cause you don't want to look for your measuring tape right now.
Start some music. Turn on a tuner or grab a radio, or both, as I did
Turn your source up. Adjust the volume of the Xmitter's Audio-In to about half way.
When you hear your new radio station, smile, because it sounds better than you thought it would, unless your expectations were unreasonably high for this type of device at this price.

Look at any clock. It's only 2:00 AM. Hand your wife your Sangean DT-160, or order one now if you don't have one 'cause it's a winner. Ask her to walk around outside to check range.

"What is this?"

"It's our new radio station."

"I thought that was the thing on my table. What is this you're handing me?"

"Cheese 'n' crackers, baby! It's a radio and headphones! People often use them to test their new radio stations."

"Oh. Well doesn't it have to connect to the station?"

"I see the source of your confusion now. You've become accustomed to that long-ass wire that connects from your car radio to whatever station you're listening to, but this works differently. It's wireless."

"Smart-ass," she's laughing in spite of herself. "Yeah, I'll go check it out."

She was gone about 20 minutes and returned to inform me that it gets fuzzy and unlistenable about four houses in every direction, but sounds nice and clear within three.

"Is this that thing you said we could go to jail over?"

"Yeah, we'll be doing hard time in a Federal prison soon, but maybe not tonight."


Some may be tempted to omit some of these steps, but I don't recommend that because I know this method works.
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.
 
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.
 
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.
 
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.

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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