Wireless Guitar Transmitter/Receiver

[DigitalJunkie]

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.

No.No.

The Aircraft band is up there,and you DO NOT want to upset those people. Not to mention if you were to interfere in a way that could cause some kind of accident,people might get hurt.
Even at low power,it's not a band I would want to monkey around in.

[AuroraB]

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!

[akis]

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.

[Iain McNeill]

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.

[AuroraB]

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£ ??????

[amptramp]

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

[Iain McNeill]

Great recycling idea!

You could even tweak it by modding the caps etc! I'd guess a baby monitor isn't too concerned with low frequencies. In terms of a reliable radio it's a great value!

[amptramp]

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.

[phase_accurate]

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

[akis]

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.