Do transmitters and receivers need antenna's to work?

Hi I'm fairly new to arduino and wireless communication. I have a code that seems to work and the hardware seems fine but do I need to add antenna's to the transmitter and receiver for it to work. It is only a foot apart though. Also do Arduino atmega 2560's have trouble with the RH_ASK library and SPI.h library because if they do I'm buying myself a couple Uno's.

For a given transmitter and receiver, the communication range is determined almost entirely by the quality of the antennas, on both.

Operating without an antenna will damage some transmitters.

Most Bluetooth and Wi-Fi devices have the antenna already etched onto the PCB. So no floating wire is usually visible or necessary. However some more advanced devices do have a socket for attaching an antenna wire but it only needs to be about 33 mm long for 2.4 GHz signals

Well I am using the 433 MHz transmitter and receiver that seems to be commonly used with arduino. So is this a type of transmitter that would be damaged?

I’m not certain if the transmitter will be damaged without an aerial, but it could be. I guesstimate the aerial should be about 8 cm long for that frequency.

The receiver aerial should be the same length.

OK so I should try the antenna and if it doesn't work then my transmitter is broken and I should get a new one.
Also if you got 2 pairs of transmitters and receivers then they would interfere with each other right?

Any transmitter of any kind would require an antenna. A receiver might still work without one but the range or strength wouldn't be acceptable. Also it is worth noting that any transmitter should not be powered on without an antenna. A transmitter generally transmits signal so if there is no antenna, the power you pumped into transmission goes nowhere. If it's a sufficiently high power transmitter, that power that's going nowhere might even damage the transmitter. So any transmitter on power on requires an antenna. I would suggest you check the transmitter if it still works and move ahead.

DheerajG:
Also it is worth noting that any transmitter should not be powered on without an antenna. A transmitter generally transmits signal so if there is no antenna, the power you pumped into transmission goes nowhere. If it's a sufficiently high power transmitter, that power that's going nowhere might even damage the transmitter.

Depends what you mean by "powered on"....

I have 4 or 5, and none of them transmits when powered on. They all require me to press the PTT button on the mic or press the CW key.

(Oh and btw, afaik, all of them have circuitry that prevents them actually transmitting if I press the PTT but the SWR's too high like when I forgot to plug the antenna in like after a storm.)

jubukraa:
Depends what you mean by "powered on"....

I have 4 or 5, and none of them transmits when powered on. They all require me to press the PTT button on the mic or press the CW key.

Well transmitting without an antenna is a bad idea. That's what I meant.

No insect anatomy whatever is required. You need aerials for RF. :wink:

8675300:
Well I am using the 433 MHz transmitter and receiver that seems to be commonly used with Arduino. So is this a type of transmitter that would be damaged?

Please stop the nonsense. :roll_eyes:

If you want to seriously discuss the matter, give the proper Web links for these devices.

8675300:
Well I am using the 433 MHz transmitter and receiver that seems to be commonly used with arduino. So is this a type of transmitter that would be damaged?

Assuming you're talking about the cheap FS1000A transmitter / XY-FST regenerative receive modules, they won't be damaged by using them without an antenna1, but they won't work very well.

The usual recommendation is to use a 17 cm length of 22 gauge wire as an antenna on each module. Wire gauge isn't critical, the length is 1/4 the transmit frequency wavelength and is fairly critical. The antenna is soldered to the hole label "ANT" (reverse silkscreen in my photo) on the transmit module. It's soldered to the hole near the bottom of the receiver module in the linked photo.

1Transmitters with high output power (e.g. A few Watts or more) are at risk of damage if operated without antenna. The reason is that the power that is supposed to go to the antenna and be radiated as signal is reflected back into the transmitter output stage and may catastrophically overheat the circuit. The FS1000A module simply doesn't have enough power to hurt itself in this manner.

Can be lighter gage wire too - I used 30AWG wirewrap wire in my last project. It was secured inside the plastic box and not subject to vibration so it never broke on me.

rf module antenna basics

OK so I should just solder in 17 cm of wire and I'd be good?

also the wire should be insulated right

Insulation right AND left. :wink:

It actually makes no odds, the insulation is just for the prevention of short circuits. You note that all commercial aerials have bare elements.