simple 433mhz antennas?

[NleahciM]

Hi - can anybody give me any advice on how to make a very simple 433 Mhz antenna? Could a specific length of wire work? Or what about an antenna that's actually a trace on a pcb? Sorry I'm horrible when it comes to RF

 

[Roboticinfo]

reply

What are you trying todo?

I mean what type of project are you doing?

 

[NleahciM]

Re: reply

What are you trying todo?

I mean what type of project are you doing?

I'm making a remote control for my outside lights. The only thing not designed is the antennas - everything else has been designed and tested. I've just been using short pieces of wires for antennas and the range seems to be pretty good, amazingly.

 

[Roboticinfo]

reply

Any antenna should work fine but I would recommend a antenna off of a cordless phone like a 900mhz
depending were you bought your tx/rx
it could go as far as 500 feet.

 

[DirtyLude]

Do a search on Digikey for '433mhz antenna'. I tried making my own for a while and dealt with tuning problems. I use the linx 1/4 wave whips, now. For $2.00, it's hard to justify making your own, and they look pretty professional, too.

You can see what it looks like, here:
**broken link removed**

If you want to go cheaper, they even have some cheezy helical coils for under $1.00.

 

[Roboticinfo]

reply

Didn't those antennas cost $10.00?

Anyway for stylish antennas


**broken link removed**

go to this website.

It is owned by linx Technologies
And they have a variety of antennas.

But the antennas from cordless phones are just as stylish and are good in range.

 

[chiba]

> Could a specific length of wire work?

Yep, Just make your wire the right length and it should work pretty good.

**broken link removed**

 

[Roboticinfo]

reply

That is two feet are you nuts!


But cool calculator though

 

[JimB]

A simple monopole antenna is a quarter wavelength long, only six inches.

JimB

 

[mechie]

Re: reply

Any antenna should work fine but I would recommend a antenna off of a cordless phone like a 900mhz
depending were you bought your tx/rx
it could go as far as 500 feet.

Bad advice :!:

You need an aerial that is at least close to the right size, impedance and design for your chosen frequency and task (directional/omni/...)

Start by looking at **broken link removed** for a directional
Or **broken link removed** page 16 of the datasheet gives a bit of info on wire and pcb track aerials --- I'm using these little transcievers at the minute, playing with a 16.4cm monopole on a portable keyboard and a centre-fed dipole (about 4 times the above) for a remote control system - it works for me !

 

[Roboticinfo]

reply

Mechie I use cordless phone antennas for my projects that use those 433mhz tx/rx modules and I get a good range.

Not bad advice

Good advice

 

[Nigel Goodwin]

As already suggested, a 1/4 wave whip is only short, and VERY easy to calculate - but even easier, read the datasheet for the RF modules you use, they generally give one or two exact aerial dimensions - particularly as the aerial is an important part of the licence free conditions!.

 

[NleahciM]

As already suggested, a 1/4 wave whip is only short, and VERY easy to calculate - but even easier, read the datasheet for the RF modules you use, they generally give one or two exact aerial dimensions - particularly as the aerial is an important part of the licence free conditions!.

The datasheet gave no information on this whatsoever. I think they said that a quarter wave antenna would be a good idea - but they gave no dimensions or anything like that.

 

[NleahciM]

> Could a specific length of wire work?

Yep, Just make your wire the right length and it should work pretty good.

**broken link removed**

awesome - I'll start it out with that as it's by far the simplest solution. Thanks!

 

[Roboticinfo]

reply

But you would need two feet of wire!

 

[DirtyLude]

Re: reply

Didn't those antennas cost $10.00?

Anyway for stylish antennas


**broken link removed**

I specificly said in the post that they were $2.00.

If you went to digikey and did the search I suggested, you would have seen that the antennas that came up are actually the Linx line and to be exact, the Linx 1/4 wave whip that I show in the picture is $2.03, USD.

 

[Roboticinfo]

Reply

I know you said that
I accentdently forgot to put didn't they used to be $10.00 dollars.

 

[chiba]

But you would need two feet of wire!

Hmm, i calculated a 1/4 wave antenna @ 433MHz to about:

0.56788167205542725173210161662818 ft

The only way i could get a result of "2 feet" was to take my shoes off then count

 

[Roboticinfo]

reply

Ohh I did the full length

not 1/4

 

[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.