simple 433mhz antennas?

[Nigel Goodwin]

Re: reply

But you would need two feet of wire!

A quarter wave (6.5") wouldn't work? Actually for the receiver 2 feet isn't a problem at all - but for the transmitter it would be.

He's already said that he worked it out incorrectly (full length instead of quarter). However, a full length whip would be no good for the receiver either!, although it won't damage the receiver (as it may the transmitter!), it still won't work properly - the severe mismatch will reduce the reception sensitivity just as on the transmitter it will reduce the transmitter output.

 

[NleahciM]

Re: reply

But you would need two feet of wire!

A quarter wave (6.5") wouldn't work? Actually for the receiver 2 feet isn't a problem at all - but for the transmitter it would be.

He's already said that he worked it out incorrectly (full length instead of quarter). However, a full length whip would be no good for the receiver either!, although it won't damage the receiver (as it may the transmitter!), it still won't work properly - the severe mismatch will reduce the reception sensitivity just as on the transmitter it will reduce the transmitter output.

yeah - I hadn't realized that there was a second page to this thread, so I missed his correction

So it'd be better to use two quarter wave antennas?

 

[Nigel Goodwin]

Re: reply

So it'd be better to use two quarter wave antennas?

Depends what you mean by that?.

A dipole is the basic aerial element, and is the standard against which all other aerials are compared. A dipole basically consists of a quarter wave element connected to the inner core of the coax, and another quarter wave element connected to the screen of the coax. This effectively gives a half wavelength aerial, with the connection in it's centre.

A quarter wave whip is essentially the same device, the 'ground' half of the dipole is reflected in the ground plane that the screen of the coax connects to - for a standalone aerial, you usually have a number of horizontal rods projecting sideways from the base of the aerial, on a car the car body acts as the ground plane. For a 433MHz transmitter or receiver the metal box you install it in acts as the ground plane - if you use a plastic box, it won't work as well! - often suggested PCB layouts include a ground plane in the copper track around the aerial connection.

 

[zachtheterrible]

Hi NleahciM, I've got a couple 433MHZ tx's n rx's. I just used a 36cm piece of wire for my whip antenna and it worked wonderfully.

Direct line of sight, I probably got around 500 ft or so, and the signal still showed up, I couldn't go any further to test it though (i live in tract homes :cry: )

Going through a house, I got around 100ft.

 

[xavierp_00]

antenna question too

Hi, I´m building a really small low-power reciever and I would like to know wich antenna should I use to recieve at 433 Mhz, the smaller one.. It would be great for it to be internal.. I found many different searching arround but I'm nor sure... tahnks!

 

[Superbat]

There are three kinds of the 433Mhz antennas.
1.antenna mount magnetic baseView attachment 63249
2.rubber antenna:View attachment 63250 ,which is mostly used for 433MHz RF Transceiver CC1101 Module matched
3.Mounting Adhesive antenna:View attachment 63251

 

[JimB]

There are three kinds of the 433Mhz antennas.

Did you have to resurrect a three (going on seven) year old thread to provide this snippet of information which is also wrong.

JimB