Hi Guys,
I did a search before posting, found a few threads but none of them had a solution so far.
I'm in search for a wireless guitar transmitter for my guitar. I play for my Church and also practice at home. Needless to say the guitar leads are annoying when they get tangled and could be VERY annoying when you move and they make feedback noise over your speakers! Especially in a concert or such!
Anyways, does anyone have a schematic?
Thanks
Meth
I did a search before posting, found a few threads but none of them had a solution so far.
I'm in search for a wireless guitar transmitter for my guitar. I play for my Church and also practice at home. Needless to say the guitar leads are annoying when they get tangled and could be VERY annoying when you move and they make feedback noise over your speakers! Especially in a concert or such!
Anyways, does anyone have a schematic?
Thanks
Meth
The first consideration is what frequency segment you could practically put to use. Uh - say somewhere between 100Mhz and 2 Ghz. outside this range things become very tough. Also I hope you will stick to the frequency segments that are leagal for this kind of application. UHF (Ultra-High Frequency) band has some spots that can be operated in licence free. You could start with a kit--- but RF is a complex dicipline in it's self, and will require a pretty stiff learning curve. Mabe buy an existing product and reverse engineer it? My concern is that the regulatory agencies are in place for a good reason, and a mistake in designing a transmitter can result in legal and ethical problems.
Hi methc,
I hate to tell you this, but you will be lucky if you can the performance of even a low-quality VHF transmitter with a DIY kit, or even an adapted design. I work in RF and can safely say that it's a domain that is totally unlike audio. Oscillators and tuned circuits are temperamental, and and getting them to work properly is not an easy thing for a novice.
Unless, you're not a novice in the RF field... I do agree this would be a fun project, I've even contemplated making one myself. As I recall, there was a article in ELECTRONICS NOW magazine in the nineties that had a VHF transmitter project.
If you are going to do this I suggest you use the unused exptremities of the FM band. An FM modulator is not that much harder to design than an AM transmitter. Mind you, with AM, you're pretty sure you won't bother anyone! And don'T think that because it's AM it woud sound like AM... you would full control on the frequency span since you wouldn't have to design-in a narrow audio filter. In any case, I don't really recommend using AM, it's prone to too much interference.
I hate to tell you this, but you will be lucky if you can the performance of even a low-quality VHF transmitter with a DIY kit, or even an adapted design. I work in RF and can safely say that it's a domain that is totally unlike audio. Oscillators and tuned circuits are temperamental, and and getting them to work properly is not an easy thing for a novice.
Unless, you're not a novice in the RF field... I do agree this would be a fun project, I've even contemplated making one myself. As I recall, there was a article in ELECTRONICS NOW magazine in the nineties that had a VHF transmitter project.
If you are going to do this I suggest you use the unused exptremities of the FM band. An FM modulator is not that much harder to design than an AM transmitter. Mind you, with AM, you're pretty sure you won't bother anyone! And don'T think that because it's AM it woud sound like AM... you would full control on the frequency span since you wouldn't have to design-in a narrow audio filter. In any case, I don't really recommend using AM, it's prone to too much interference.
I found this FM Transmitter while googling. Works between 80 -110MHz FM.
I'm aware of the legal issues surrounding using certain frequencies on the airwaves and I'm obviously working around them to be on the safe side. Thanks for the tip tho, was all good...
Can you guys take a look at the schematic, let me know what you think.
Does anyone have a good receiver schematic that will tune to the 80-110MHz FM range?
See you guys around.
Thanks.
Meth
I'm aware of the legal issues surrounding using certain frequencies on the airwaves and I'm obviously working around them to be on the safe side. Thanks for the tip tho, was all good...
Can you guys take a look at the schematic, let me know what you think.
Does anyone have a good receiver schematic that will tune to the 80-110MHz FM range?
See you guys around.
Thanks.
Meth
The schematic you found is for a LC tuned local oscilator witch has the draw back of being not frequency stable enough. You are going to have to find a design that uses a crystal as the local oscilator. It's leagal to transmit in the FM band without a licence but the power is restricted to such a low level that the range is typicaly limited to somthing like a couple of feet. This restriction is the effective radiated power, so there is no better antena or higher power that can be employed. Also the interfearance issue is a tough one. Try searching some similar products and see what frequencies they use. Also look up ISM band witch is the industrial sientific medical band. Look at how other people have delt with this question.
A simple FM transmitter at 70-120MHz is dead easy to build. Quality is perfect with FM modulation, sound will be very clear. There are some slightly more advanced tranmitters employing two transistors at the output stage for more power, but I doubt you'd need that in a church hall.
A simple transmitter, like the one you have shown above (I remember from memory those days we used the 2n2219/2n2222A not the BC54x series) that one will drift as others have said, it will drift with temperature, baterry power, and so on. Even if you wax the coil it will still drift. So the receiver at the other end will need to be constantly adjusted.
So you are looking for a schematic employing a crystal or PLL or something to make sure the frequency stays put.
A well designed transmistter using 2-3 transistors would last at least 6-9 hours using a 9V PP3 battery, no need for the bulky AAs.
At the other end you will need a receiver. Unlike the transmitter you are in luck, because space is not at a premium backstage, so you could use an ordinary radio, something with PLL and a digital display maybe.
Here is the trick. You open up the radio, find it's tuning circuitry and adjust it so it can receive 10%-15% off one side of the 88MHz-108MHz FM band! eg you tweak it so that it covers 80MHz-100MHz. I have done this many times, there is usually a set of variable caps you can mess with, dead easy to spot, mostly driven straight off the tuning knob (or via a belt/cable).
By tuning down to say 86MHz, you are ensuring that nothing else can interfere with you since commercial FM stations start, at best, at 88MHz. Or you can go the other way, eg 110MHz, 2MHz off the top 108MHz.
It could be said that you'd be breaking regulations by transmitting into bands you should not but I have two things to say. First your transmitter is so powerless that it would hardly make it backstage, let alone outside of the premises. Secondly many, hundreds or thousands of amateur hobbyists build radio transmitters, and while experimenting, and sometimes while not, they mistakenly transmit all over the place, what with harmonics, bad tuning pots etc. So they all do it, one way or the other. Finally as you are so close to the 88-108 range, it should not matter, eg 87MHz should be fine.
Of course someone is going to jump up and inform me that 87MHz is the frequency allocated for monitoring equipment at cardiac departments in hospitals or the well publisized frequency for remotely manipulating the control rods in your local nuclear power generator... Whatever
A simple transmitter, like the one you have shown above (I remember from memory those days we used the 2n2219/2n2222A not the BC54x series) that one will drift as others have said, it will drift with temperature, baterry power, and so on. Even if you wax the coil it will still drift. So the receiver at the other end will need to be constantly adjusted.
So you are looking for a schematic employing a crystal or PLL or something to make sure the frequency stays put.
A well designed transmistter using 2-3 transistors would last at least 6-9 hours using a 9V PP3 battery, no need for the bulky AAs.
At the other end you will need a receiver. Unlike the transmitter you are in luck, because space is not at a premium backstage, so you could use an ordinary radio, something with PLL and a digital display maybe.
Here is the trick. You open up the radio, find it's tuning circuitry and adjust it so it can receive 10%-15% off one side of the 88MHz-108MHz FM band! eg you tweak it so that it covers 80MHz-100MHz. I have done this many times, there is usually a set of variable caps you can mess with, dead easy to spot, mostly driven straight off the tuning knob (or via a belt/cable).
By tuning down to say 86MHz, you are ensuring that nothing else can interfere with you since commercial FM stations start, at best, at 88MHz. Or you can go the other way, eg 110MHz, 2MHz off the top 108MHz.
It could be said that you'd be breaking regulations by transmitting into bands you should not but I have two things to say. First your transmitter is so powerless that it would hardly make it backstage, let alone outside of the premises. Secondly many, hundreds or thousands of amateur hobbyists build radio transmitters, and while experimenting, and sometimes while not, they mistakenly transmit all over the place, what with harmonics, bad tuning pots etc. So they all do it, one way or the other. Finally as you are so close to the 88-108 range, it should not matter, eg 87MHz should be fine.
Of course someone is going to jump up and inform me that 87MHz is the frequency allocated for monitoring equipment at cardiac departments in hospitals or the well publisized frequency for remotely manipulating the control rods in your local nuclear power generator... Whatever
Simple transmitters like this are NEVER stable enough nor CLEAN enough not to disturb other services - and then your in deep s**t! You need at least X-tal controlled accuracy in both ends.
And the possible interference to the aircraft band is indeed a serious problem!
Unless you're seriously skilled in RF design and layout, - forget it.
Take the advice and get a proper set, even second hand!
And the possible interference to the aircraft band is indeed a serious problem!
Unless you're seriously skilled in RF design and layout, - forget it.
Take the advice and get a proper set, even second hand!
OK it seems 108MHz+ is bad. A bit less than 88MHz is not that bad though, TV channels it says, I suppose it varies from country to country. How about spot on 88MHz? How many radio stations transmit on 88MHz?
Then, there are also those commercial iPod/MP3 player FM transmitters - I presume since those things are freely for sale, one is allowed to transmit at 88-108MHz if power is low.
Then, there are also those commercial iPod/MP3 player FM transmitters - I presume since those things are freely for sale, one is allowed to transmit at 88-108MHz if power is low.
Agreed.
The problems of cable tangle and loose connections are much more easily solved than getting an FM transmitter to work properly.
Imagine the transmitter drifting off frequency in the middle of a song and blasting white noise out instead. Or a ghost image suddenly capturing the channel and suddenly blasting out Black Sabbath (or worse)!
Now if you want to learn about RF electronics, that's a completely different story.
The problems of cable tangle and loose connections are much more easily solved than getting an FM transmitter to work properly.
Imagine the transmitter drifting off frequency in the middle of a song and blasting white noise out instead. Or a ghost image suddenly capturing the channel and suddenly blasting out Black Sabbath (or worse)!
Now if you want to learn about RF electronics, that's a completely different story.
That's essentially correct- but these TX-s are tiny power , designed for distances of a few meters only. Even moving yourself behind a speaker rack may cause crackles and pops.
OTOH - some frq.s in the 45 MHz band were used in several countries. These also had TX-s for lavalier mics, which could be adapted to a guitar. These ought to be fairly cheap if you can find one. Modern systems mostly use diversity receivers which are much less prone to signal change as you move around in a room or on stage. The cheaper systems go for around 300£ here in Norway, and are probably about 2/3 in the UK - a used system maybe 100£ ??????
OTOH - some frq.s in the 45 MHz band were used in several countries. These also had TX-s for lavalier mics, which could be adapted to a guitar. These ought to be fairly cheap if you can find one. Modern systems mostly use diversity receivers which are much less prone to signal change as you move around in a room or on stage. The cheaper systems go for around 300£ here in Norway, and are probably about 2/3 in the UK - a used system maybe 100£ ??????
This discussion came up in the Analogue subforum, so I will repeat what I said there:
I have a real low-budget rock-bottom ghetto approach to this: My daughter has a number of guitars, some of which are good quality and some of which are "beaters". This is for her own use around the house with one of her beaters, a Chen Yi guitar that I got at a garage sale for $20 (actually a pretty good guitar).
The main purpose is being able to move around without tripping over wires, so I have modified a Fisher-Price baby monitor with the transmitter taken out of its case and buried in the guitar. The slide switches can be moved with a key, but I intend to drill the case at some point where there is no acoustic resonance and install miniature toggle switches and a small battery holder, which I have not done yet.
The receiver can be connected to a proper amplifier as the monitor electronics was never intended to reproduce anything remotely close to high fidelity, but there is no doubt better fidelity ahead of the output amplifier.
The electronics in the units (once you get rid of the cheesy plastic cases) appears to be reasonably high quality.
You can modify the electronics to achieve pretty well any frequency response you want. The monitor was $2 at a garage sale and offers two frequencies to avoid interference.
So something designed to listen to
leaves me
I have a real low-budget rock-bottom ghetto approach to this: My daughter has a number of guitars, some of which are good quality and some of which are "beaters". This is for her own use around the house with one of her beaters, a Chen Yi guitar that I got at a garage sale for $20 (actually a pretty good guitar).
The main purpose is being able to move around without tripping over wires, so I have modified a Fisher-Price baby monitor with the transmitter taken out of its case and buried in the guitar. The slide switches can be moved with a key, but I intend to drill the case at some point where there is no acoustic resonance and install miniature toggle switches and a small battery holder, which I have not done yet.
The receiver can be connected to a proper amplifier as the monitor electronics was never intended to reproduce anything remotely close to high fidelity, but there is no doubt better fidelity ahead of the output amplifier.
The electronics in the units (once you get rid of the cheesy plastic cases) appears to be reasonably high quality.
You can modify the electronics to achieve pretty well any frequency response you want. The monitor was $2 at a garage sale and offers two frequencies to avoid interference.
So something designed to listen to
leaves me
Great recycling idea!I also have a set of Advent AW820 wireless speakers here. The transmitter is a relatively small D-shaped unit about 4" in diameter that could be made to fit a guitar easily. I got the transmitters and speakers new in the box for $20 at a garage sale. Decent units although the noise floor is a little high.
There is an analog control for frequency tuning on both the transmitter and the receiver/speaker assemblies that can provide a minor shift in frequency. Each speaker can be switch-selected to be left channel or right channel and you could broadcast in stereo to give the effect of a pickup at the frets and at the bridge if you want to get elaborate. The transmitter takes an input from my computer headphone jack, so you would have to cobble up a microphone and preamp to feed it.
This is an alternative to the baby monitor that I mentioned above.
There is an analog control for frequency tuning on both the transmitter and the receiver/speaker assemblies that can provide a minor shift in frequency. Each speaker can be switch-selected to be left channel or right channel and you could broadcast in stereo to give the effect of a pickup at the frets and at the bridge if you want to get elaborate. The transmitter takes an input from my computer headphone jack, so you would have to cobble up a microphone and preamp to feed it.
This is an alternative to the baby monitor that I mentioned above.
In Europe for instance it is leagal nowadays to use small FM transmitters in the FM broadcast band. But they are restricted to some microwatts only. These can be used to "connect" your iPod to the car radio for instance (and they do therefore come in stereo).
So the FM band would be an option in Europe for instance but you would have disadvantages like others have mentioned already.
Professional wireless equipment uses frequency bands that are internationally assigend for this purpose (in some parts of the world they are endangered by DVB-T nowadays).
Regards
Charles
So the FM band would be an option in Europe for instance but you would have disadvantages like others have mentioned already.
Professional wireless equipment uses frequency bands that are internationally assigend for this purpose (in some parts of the world they are endangered by DVB-T nowadays).
Regards
Charles
In terms of what is legal I think 88MHz and 108MHz would be great to use and with 1000s of commercial radios to plug to your amplifier back stage.
There are also those TV home units in the 2.4 GHz band you do not need a license for, but that area is really congested, almost anything these days uses it.
There is another band at 400-odd MHz which is free to use - I remember a house alarm remote was using this frequency.
And car key remotes maybe use some other frequency?
****
In terms of signal quality the question would be would a transmitter function uninterrupted, considering its location, eg attached to one's belt, and with a person moving in and out of sight of the receiver, perhaps behind obstacles like concrete/marble columns - I am imagining a cathedral ?
What frequency would be the best to use to minimise local blind spots so to speak? I presume the lower the frequency the better, eg short waves or even long waves - those would not be affected by obstacles (eg people, columns etc) ?
My wireless at home, at 2.4GHz, drops a million packets when people walk in and out of rooms - definitely affected.
There are also those TV home units in the 2.4 GHz band you do not need a license for, but that area is really congested, almost anything these days uses it.
There is another band at 400-odd MHz which is free to use - I remember a house alarm remote was using this frequency.
And car key remotes maybe use some other frequency?
****
In terms of signal quality the question would be would a transmitter function uninterrupted, considering its location, eg attached to one's belt, and with a person moving in and out of sight of the receiver, perhaps behind obstacles like concrete/marble columns - I am imagining a cathedral
?What frequency would be the best to use to minimise local blind spots so to speak? I presume the lower the frequency the better, eg short waves or even long waves - those would not be affected by obstacles (eg people, columns etc) ?
My wireless at home, at 2.4GHz, drops a million packets when people walk in and out of rooms - definitely affected.
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