FM Transmitter

[musichal]

Did I deal with the noise gracelessly?

My experience with the TIVDIO 15w FM Transmitter:

Initially, I thought it sounded pretty good, and so did Christine. I began with some classic rock music - older recordings with limited dynamic range. As I began to broadcast better recordings, I found that I had to turn the level down a lot to help ameliorate some very nasty midbass distortion on program peaks. Of course, I tried different levels of both source output and the Audio input level of the Xmitter itself, but could find no combination to bring that mb distortion down to a listenable level because as the levels came down, the frying noise intruded.

It seemed that the background fry noise became louder as the music level declined. Now, if it had been a ssshhh sort of background, I could live with that. Maybe. However, this was a nasty, crackly, spikey fry - sort of like like bacon popping and snapping, but without the pleasant aroma and appetite anticipation. Unlistenable. Well, you could, as long as you didn't expect to enjoy it.

A compressor (was considering a Cuthbert, if I could get one) would likely help. As it was, the happy medium between background noise at low program levels, and very high midbass distortion proved to be anything but happy. Understand, the distortion was very high, far into double digits, I'm sure [if someone measured and told me it was 44% at its worst, I would not be surprised]. Nor was the fry simply a smooth whoosh that tends to be masked by program material. Needs compression, either by choice of recording, or maybe a compressor, is my take.

I don't believe my expectations were unrealistic - even at its best, with dynamically-challenged recordings - there yet remained some background fry that was masked by rock or country music, ie, selections without quieter passages, and I expected that [some midbass distortion remained, too, but further down in level]. I did not expect the Xmitter's highly objectionable distortion and noise with more dynamic recordings. If I ever decide to pursue FM Xmission further, it won't be with this unit.

 

[Punker X]

Did you try turning down the level of the input? May have been over modulating. I often have to readjust when changing streams or sources.

 

[musichal]

Did you try turning down the level of the input? May have been over modulating. I often have to readjust when changing streams or sources.

Yes, I think you missed that when scanning my often too-long posts. I tried almost every conceivable combination of both source output level and the Xmitter's Audio Input level. With the level high, I got what I was sure was over-mod distortion showing up first as mid-bass distortion, exacerbated greatly on program peaks; as I brought the level down, via any combination of output and input control settings, the ever-present fry in the background increased to the point that it was unmasked by program, ie, music. And the lower in level, the nastier the fry. The result was that it sounded okay (not really good) with recordings, or music sources, that compress dynamics.

Many people apparently use these for Christmas display sound, and I can see it being passable for that, or for a PA at a car show where folks can simply hear announcements over their radios, as one Amazon buyer uses it. But for listening to music on my not-yet-built new patio, I will resort to running wire, using a radio, or some other method. Of course, the Cuthbert compressor I mentioned above (positive review by radiojay) could be a possible solution, but Sean builds them one at a time, is getting more interest due to the review, has parts on order that delay more production for about two months... sells them via ebay, and you have to watch for them to come up. I didn't ask if I could reserve one - I wanted to check out the transmitter first.

https://radiojayallen.com/cuthbert-6-channel-3-band-stereo-audio-compressor/

 

[Bill Ferris]

Musichal FWIW, I built and have used the unmodified Ramsey 100B for over 19 years ago, used with their optional outside PVC antenna elevated 36`, fed with 100ft of RS branded Tandy RG- 6.
And had friends drive over a mile in both N, S, and W(E wasn`t checked because of the river across the street) directions from my house, and reported to me that my "WBIL" signal sounded excellent until they hit the fringe of my coverage area, which this distance was unintended.
I setup this FM XMTR. to provide my all day classic rock music from my Big dish sat. HQ DMX digital radio feed, or CD selected from my living room`s A/V rack Mac. C 37 preamp primarily to provide my music to a recently added attached garage, which was built after I had paid somebody to already run L/R audio & a composite video feed cables to all the other rooms in my house years prior.
Plus as a side benefit, for my next door neighbor B-I-L, could tune in to my station and hear straight music with full quieting on his Garage`s receiver with no stupid brainless commercials, heavy audio compression etc. from our local FM fare while he tinkered around out there.

I left the Ramsey running 24/7/365, and the only time I had to adjust the audio input level control was when somebody came over with a very hot overly compressed CD to have me play, that the super stupid local recording studios had pushed the master burn levels so hot (because that`s what the general public wants hear, and we all know louder is better!!) that it clipped the Ramsey`s audio input frontend.
After a handful of that noise experiences, I just flat out refused to play any local recording burns from them through my system ever again !

The 100B has a switch selectable fixed compressor/limiter, but I never used it because my music source`s where pretty close enough to set the input level at the hottest CD modulation level and not worry about the slightly lower levels of other recording media fed to it, since I had full quieting there was no reception hiss, if I chose to turn up the receiver`s volume slightly for the less hot recorded music.

Any way, if you ever decide to look into a FM XMTR again, look at the Ramsey 100B, or whatever variation they now offer(I built mine on a TV tray table, because both benches were occupied) and with the use of only one hand ..

Good luck, whichever route you chose.

Kind regards, OKB

 

[Bob@FM]

With the level high, I got what I was sure was over-mod distortion showing up first as mid-bass distortion, exacerbated greatly on program peaks; as I brought the level down, via any combination of output and input control settings, the ever-present fry in the background increased to the point that it was unmasked by program, ie, music. And the lower in level, the nastier the fry. The result was that it sounded okay (not really good) with recordings, or music sources, that compress dynamics.

I'm really glad you sent it back. At 15W, or even 2W, this is WAY too much power for homeowner use. It's very likely you were severely overloading the input RF stages on your FM tuners (which does not sound good). You are just way too close to the transmitter at those power levels.
Here's another decent unit that works OK for many - the $50. CCrane unit.
https://www.ccrane.com/item/acc_tra...nsmitter_2_for_sending_near_broadcast_quality

I tested one of these (the original version) for my friend Ray, it was OK, not by any means bad, and extremely listenable.
The results are still over at Yahoo FMTuners (in files) if anyone is curious.
I see that this new version, like the original has a hidden pot inside you can adjust to increase range. see here
http://bellgab.com/index.php?topic=9294.0

Even with the above adjustment made to max power, you will still be close to low 100mW power. Which should easily give you 1/4 mile + range, if you position the antenna in a good location (usually higher = better, i.e. upstairs versus in the basement). Also you should make sure the receive antenna is oriented like the transmit antenna, i.e. both either horizontal, or vertical. Give it a try.
Bob

 

[Watthour]

I have two of those, one smaller than the other. I won't mention the output wattage, but suffice it to say that I can tune the larger one on the truck radio about 5 miles away. I can drop the output wattage to a much lower level for use in the neighborhood.

 

[FrostEOne]

I have a 192 channel Christmas display choreographed to music, the whole house fm transmitter works great for this, reasonably priced and legal too.
https://wholehousefmtransmitter.com/

 

[I LIKE MUSIC]

I ran across this PDF awhile back. I do not know this person or have any knowledge of his technical expertise.

It is an interesting read comparing the RF field strength of several Part 15 FM transmitters,, although not much about audio quality.

Note the increase in RF signal strength for the Whole House 3 transmitter when an audio input cable is plugged in. This is not necessarily surprising since it supplies at least in a small part the missing RF counterpoise for the antenna.

Also note that the C.Crane transmitter comes from the factory adjusted for a rather low output power, but is adjustable to considerably higher power and range.

This information is several years old and may not be accurate for newer units.

 

[FrostEOne]

I ran across this PDF awhile back. I do not know this person or have any knowledge of his technical expertise.

It is an interesting read comparing the RF field strength of several Part 15 FM transmitters,, although not much about audio quality.

Note the increase in RF signal strength for the Whole House 3 transmitter when an audio input cable is plugged in. This is not necessarily surprising since it supplies at least in a small part the missing RF counterpoise for the antenna.

Also note that the C.Crane transmitter comes from the factory adjusted for a rather low output power, but is adjustable to considerably higher power and range.

This information is several years old and may not be accurate for newer units.

I have noticed many things that effect performance of this unit, including the input level from source and level settings on both input options. Wasn't aware of Canadian setting. Good information to know, thanks

 

[musichal]

I ran across this PDF awhile back. I do not know this person or have any knowledge of his technical expertise.

It is an interesting read comparing the RF field strength of several Part 15 FM transmitters,, although not much about audio quality.

Note the increase in RF signal strength for the Whole House 3 transmitter when an audio input cable is plugged in. This is not necessarily surprising since it supplies at least in a small part the missing RF counterpoise for the antenna.

Also note that the C.Crane transmitter comes from the factory adjusted for a rather low output power, but is adjustable to considerably higher power and range.

This information is several years old and may not be accurate for newer units.

That is indeed an interesting account. Wish I'd run across it prior to my selection and/or try-out of the TiVdio. Thanks for posting it. If I decide to pursue FM transmission, I might try the CCrane before ordering a Ramsey 100b.

 

[FrostEOne]

Back in the 70's I knew a fella that used a TV antenna amplifier as a transmitter with a roof top antenna, it would go about 5 blocks in an uptown area.

 

[I LIKE MUSIC]

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

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



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.



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.

Back in the 70's I knew a fella that used a TV antenna amplifier as a transmitter with a roof top antenna, it would go about 5 blocks in an uptown area.

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.

 

[I LIKE MUSIC]

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

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.

Back in the 70's I knew a fella that used a TV antenna amplifier as a transmitter with a roof top antenna, it would go about 5 blocks in an uptown area.

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.

 

[FrostEOne]

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

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.

I just called him, just a pair of Winegard TV antenna amps in series, he worked in a TV repair shop. Remember them?

 

[I LIKE MUSIC]

I just called him, just a pair of Winegard TV antenna amps in series, he worked in a TV repair shop. Remember them?

I owned one and my shop was an authorized Winegard dealer.

Without modification, and amplifier is just an amplifier, not a transmitter.

Show me the audio input on Winegard TV antenna/distribution amplifier.

 

[FrostEOne]

I owned one and my shop was an authorized Winegard dealer.

Without modification, and amplifier is just an amplifier, not a transmitter.

Show me the audio input on Winegard TV antenna/distribution amplifier.

I agree with you, he is holding something back. Sorry for incorrect info.

My dad had a TV repair business when I was young, but that was 60 years ago. I remember when color TV came out!

 

[I LIKE MUSIC]

FrostEOne, to be clear, I mean no disrespect and I am not trying to pick on your posts. But there are over 900 hits on this thread and I am just trying to supply, to the best of my somewhat limited ability, mostly accurate information.

BTW, I remember when the transistor was invented. Common wisdom of the time said that it was too performance limited to amount to much and it would never replace the vacuum tube in most applications.

Okay, this is not meant to open up a debate regarding solid state vs. tube audio gear.

 

[musichal]

I'm disappointed too. Was about to make an order. Maybe it was just a bad unit, just about all the reviews were quite positive with references to quiet dead air operation... on the other hand I really wanted to hear good news so I might be projecting some of those hoped for expectations. Leaves me wondering why.... I mean, now hard can it be to make a decent low power FM transmitter now days....

Well, it is entirely possible that my experience with it was largely human error, too. Give it a go and see what you find. I think either the CCrane or the Ramsey would likely be better options, though. I'd believe anything PunkerX says about RF stuff, which biases me toward the 100b if I decide I want to play with a transmitter.

 

[I LIKE MUSIC]

BTW, sorry for the double post above. I was having an issue with my internet service and I may have pushed the button more than once, or maybe it is just my age, health and medications...

 

[FrostEOne]

FrostEOne, to be clear, I mean no disrespect and I am not trying to pick on your posts. But there are over 900 hits on this thread and I am just trying to supply, to the best of my somewhat limited ability, mostly accurate information.

BTW, I remember when the transistor was invented. Common wisdom of the time said that it was too performance limited to amount to much and it would never replace the vacuum tube in most applications.

Okay, this is not meant to open up a debate regarding solid state vs. tube audio gear.

I LIKE MUSIC No disrespect taken, I understand where your coming from. I'm here to learn and absorb info, if I need corrected, so be it!