AT86RF212 Antenna Brickwall

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#1
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Hi,
I would like to make a remote control device for my gate. I checked my local supplier and they can only bring in the AT86RF212 (dont have stock of the AT86RF230/1). I like the idea of the added range of the RF212! Imagine pushing a button to open your gate like 200m away, then by the time you arrive home its open!

The gate controller is going to be mounted in a metal box (Its what I already have), so I would like to use an external Antenna. For the remote control I presume I use a small SMD ceramic antenna?

The AT86RF212 seems like a fantastic device, but trying to get a balun and antenna is really possing a big problem for me.

I have been googling for ages with no success with regards to a commonly available antenna's (also checked the datasheet). I am from South Africa and I dont care if the antenna is anywhere between 700 to 900MHz, its just needs to be a common part that I have a hope of buying!

I can only find lots of App Notes for the AT86RF230 antenna, nothing on the AT86RF212.

This is the best results for an antenna my googling has found:
http://uk.farnell.com/lprs/ant-9...
But its about 7 british pounds!!!

I will read anything anyone points me too! Thanks for any help.
This antenna stuff seems like a black art secret :?

Just a noob in this crazy world trying to get some electrons to obey me.

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Not many commercially available antennas out there for 800MHz. That isn't used in the US (about 910MHz is) but it IS used in the E.U. That is probably why you have having difficulty.

My gate opener has just a wire antenna poking up from the top of the box. It is insulated copper, about the gauge of house wiring. At this frequency, I don't think that you need much in the way of a "special" antenna. The metal box will make a nice "ground plane" for it. The wire comes through the box with a compression fitting; it is waterproof, plastic, and has a compressed rubber ring around the wire that seals it.

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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Do you really want to be able to open up your garage from 200m away? That's quite an distance, likely not within visible range. Great way for unexpected 'visitors' to get in unseen. Or imagine accidental activation while you cannot see the garagedoor, it could means that your garagedoor remains open until you get back. I would prefer something like 20..30m range.

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He is talking about a gate opener. Not garage door. I don't even have a garage door, let alone a garage door opener, but I have a gate with a remote opener. Great to keep stray livestock from going where they should not or people out who think your entrance is a highway.

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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ka7ehk wrote:
Not many commercially available antennas out there for 800MHz. That isn't used in the US (about 910MHz is) but it IS used in the E.U. That is probably why you have having difficulty.

My gate opener has just a wire antenna poking up from the top of the box. It is insulated copper, about the gauge of house wiring. At this frequency, I don't think that you need much in the way of a "special" antenna. The metal box will make a nice "ground plane" for it. The wire comes through the box with a compression fitting; it is waterproof, plastic, and has a compressed rubber ring around the wire that seals it.

Jim


Ah ok, a piece of wire it is then! I was wonder are those plastic black antennas that can rotate and bend 90 degress, are those just a plastic housing with a wire in it? Nothing special like you say?

ka7ehk wrote:
or people out who think your entrance is a highway.

lol

Just a noob in this crazy world trying to get some electrons to obey me.

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Hi,

You check out some antennas from http://www.johansontechnology.com/ they are available on digikey. But also use the matching network that the recommend. I have used their antenna but along with my PA and LNA so I get much better performance on RF212. However I had been trying out lately on Direct coupling using a shielded thick 24AWG wire. The results with a 100pF cap are really satisfying with a net return loss of -6db on the antenna. Hope that it helps.

AVR Rulez...;-)

Warm Regards,
Boseji
http://m8051.blogspot.com/