I need to transmit data wirelessly but do not want to use an antenna at all. I am trying to use the RF-LINK 2400 bps. Transmitter andd receiver are each connected to 5V. Testing the range a few days ago, I was able to walk all over the house and still receive the signal. Today, I can only move a few meters away and lose signal. When using long wire as antenna I can move farther away like I did without the antenna a few days ago. Any ideas?
I looked at other products with a built in antenna but they are too expensive ( I am trying to put 20 prototypes together) and run on 3 V.
I don’t need speed for transmission. Know of any inexpensive (~$10)products out there that will give better range without antenna (or with one built in) running 5V?
amirbaram:
I need to transmit data wirelessly but do not want to use an antenna at all. I am trying to use the RF-LINK 2400 bps. Transmitter andd receiver are each connected to 5V. Testing the range a few days ago, I was able to walk all over the house and still receive the signal. Today, I can only move a few meters away and lose signal. When using long wire as antenna I can move farther away like I did without the antenna a few days ago. Any ideas?
I looked at other products with a built in antenna but they are too expensive ( I am trying to put 20 prototypes together) and run on 3 V.
I don’t need speed for transmission. Know of any inexpensive (~$10)products out there that will give better range without antenna (or with one built in) running 5V?
Thanks,
Amir
Unless you are transmitting at very close range, have a rediculous amount of power, or have a very long balun… you definitely need an antenna.
maybe you should understand what an antenna is. I know this isn’t precise but it’s part of a tuned circuit that resonates at the desired radio frequency. in order to transmit or receive, by definition, you must have an antenna.
now, I’m sure you mean something you purchase that has a connector on it and so on. but, all you need is a resonant length of wire. Your first experiment probably had something resonant acting as an antenna. In it’s simplest form, a quarter wave whip for 433.9 mhz is just a length of wire approximately 6.5" long. best orientation is vertical.
for my rf-link 2400, I use a 6.5 inch length of #24 solid core wire pushed into a solderless breadboard (receive and transmit). The transmitter is running on 3.3V and I get about 150 ft going through 3 walls and a floor.
Thanks for your reply philba. I was able to get the range back by changing to a fresh 9V battery. Power is supplied from 9V through MAX667 regulator to 5V. I thought that since the Max667 ouputs 5V constant (which goes to the transmitter) then the range shouldn’t change over time as long as the circuit stays at 5V. But the range has dropped drastically when 9V battery is down to 7.5V. Does that make sense?
Thanks guys I will connect an antenna. I would like to add a removeable antenna. Which antenna should I use (cannot just use a wire) and which connector?