So.........For this weeks small project: I've been thinking over the last week or so, how can I transmit Bluetooth audio as well as line level audio in stereo around my medium sized flat Now I bought one of those FM transmitters back in 2015 that had a claimed 15 to 20 mile radius if placed up high enough! These only have a line in facility though & as it turned out they also cause interference to just about everything - Spurious emissions that knocked out my Wi-Fi, Freeview TV & Freesat, so I quickly decided I wouldn't be using it at all as it would be doing the same next door & flats upstairs too! Not only that, the signal was indeed so powerful it was overloading the front end of the tuners in many of my boomboxes to the extent that the results were terrible! I've been thinking over the last week or so, how can I transmit luetooth audio as well as line level audio in stereo around my medium sized flat! I have a cheap device in my car that allows Bluetooth audio & handsfree calling that simply plugs into the cigarette lighter socket & allows me to use the existing Tuner/CD player without messing with the car stereo at all! Car comes with factory fitted JBL speaker systems front & rear & they are simply excellent so with a decent factory stereo in perfect working order, this little device is perfect! A couple of days later & another similar device arrived along with a car cigarette lighter socket - I chose to keep it as simple as possible after the expensive transmitter mistake in 2015, cheap as well so I had nothing to lose! I have a new unused 10 Amp high quality regulated power supply doing nothing but sitting it's box! This is a beautiful supply & it's 13.8 supply is overkill for such a tiny device but as I had it already was the reason I chose this route! With all the gubbins in front of me, it was definitely time to break for a hot sponge pudding You can't beat that Dr Kipling Pudding digested & energy levels up, out came the soldering iron & some thick gauge red/black cabble it took just a few minutes to extend the somewhat stingy caable from the new socket to a decent length using heat shrink wrap to cover the soldered join!! Mount the socket part on the upright poles of my corner shelves, connect the power supply up & perform tests!! I almost tripped over my perch The results were just excellent in all the rooms, even the little Fisher/Sanyo mini Hi-Fi in the bedroom which is through 3 walls was able to pick up hiss free FM stereo! Result!! & of course all my beloved boomboxes (I hate that word!) can now easily tune in to 94.4 FM & produce lovely stereo sound......... I have a cheap device in my car that allows Bluetooth audio & handsfree calling that simply plugs into the cigarette lighter socket & allows me to use the existing Tuner/CD player without messing with the car stereo at all! Car comes with factory fitted JBL speaker systems front & rear & they are simply excellent so with a decent factory stereo in perfect working order, this little device is perfect! Oh yeah: I paid £16 for it & cigarette adapter was £2! Naturally I am up over the moon with the end result......... I can now listen to "Orange FM" easily & effectively!! Et Viola: 4K video here as Youtoob have caught me out just like a kipper & refused to let me post so go here: https://1drv.ms/v/s!ANEYKw-3GKK-gqwA
St.Nick, your ingenuity Strikes Again!!! Quite a few folks at Boomboxery have their boom-rooms, and I could never figure how they make the whole wall of bboxes play one tune... and no one of those Lucky Dudes would enlighten me Now I know how to make them all come alive at the same time, and to the same tune... (((once I get there again... ...but of course I will... I have only four now: presents from @Boodokhan and from @Longman and two "survivors" from my burned collection )))
I use an FM Transmitter from FMUser. The audio sources it can accept include Line, SD cards, and BT. It even has a rechargeable battery so you can take it outdoors. It is only 0-1 watt, but I only need 2 or 3 tenths of a watt at home. There's no need for 1+ watts unless you need to broadcast to other people.
I'm still on the fence for which FM transmitter I should get, I've been using them for years in my car but I keep getting that scratchy sound that almost sounds like the old dial up modems. It happens about every 10 minutes and I still don't know what it is, I've heard two theories, one is it might be an incoming call checking your phone ID or theory two is that it's the cell phone towers changing. Are you getting any of that interference? I'm leaning to something like Reli has, they're pretty cheap now and I've dreamed about having a transmitter since I picked up a soldering iron as a kid. I recently talked with a HAM Radio guy on a jobsite and he said the Feds will track you down fast if your signal is too strong and the fines are huge. In the old days they used to monitor more heavily, mostly for the CB band for the guys that would tweek their equipment and extend their range exponentially.
I haven't found any that sound as good as a real FM station. The bass isn't as good. Really it's just a convenience item, useful for outdoor events and drive-in movie theaters.
I might have to dig into the old electronic's magazines and build one. I assumed the signal would be linear but pushing the bass must take more power. This is the kind of stuff that's fun to go over with some beverages on a Friday but all the electronic nerds around here are over 80 and nobody else has interest.
Well most of them say things like "frequency response 50Hz to...." in the specifications, so apparently there's a dropoff in bass......Not sure why. Otherwise why would they even mention it. Maybe it even starts to drop off at 100, and 50 is just an arbitrary point they chose to state. But consider that CD players start at 20 Hz or less. So these transmitters would prevent some of that low bass from happening. Also there's nearly always a hum between songs, caused by interference from the AC cable, your RCA cables, or just low-quality componentry inside the transmitter.
On a boombox the quality is more than acceptable, I guess on a proper Hi-Fi tuner in a system one could be picky & listen for any losses - I get no dropouts in here or in the car! Audio CD's sound better in the car but they would of course..........I like having access to my entire music collection with random play mode activated most of the time! Stereo separation is above average for a cheap transmitter & phone calls are hands free too as the module has a built in microphone with no pain in the ass manual mics to route & mount in the car! No hums or hissing from my two, not yet anyway.......... A purpose built transmitter would be much better I would guess........
I didn't know they didn't have a full frequency response on the FM Band, over here it's limited "The (L+R) Main channel signal is transmitted as baseband audio limited to the range of 30 Hz to 15 kHz" https://en.wikipedia.org/wiki/FM_broadcasting Maybe the smaller transmitters are limited even more?
Yeah 15 khz has always been the upper limit on FM & remember that most if not all stations use a high range of compression which was never the case in the 70's & early 80's!! The warm sound of FM is long gone
We have a few stations trying really hard over here, but it's not like the old days where they tried hard to have the cleanest, best-sounding signal. Believe it or not several stations still play vinyl and they love to advertise it, no one listens to digital radio over here, I've never seen a digital reciever except Amazon.com, so analog is here to stay for a long time, thankfully.
Also: https://darrylparks.com/2015/10/20/why-your-favorite-fm-station-doesnt-come-in-as-good-anymore/
St.Nick, you strike again! I must try this with my 2+terabytes collection... If you won't hear from me again it means that I gone totally crazy: mix of Pink Floyd, Klaus Schulze, BeeGees, Mahler, Schubert, LadyGaga, KanyeWest (being a collector, I find it hard to delete Garbage) may finally accomplish The Thing by Boss is saying about me
