Can I locate the RF antenna away from the emonTx?

Submitted by crispin on Thu, 08/10/2015 - 20:10

Bit of a newbie question here, but is it possible/easy to locate the antenna away from the emonTx (or emonPi) unit? I will need to get a signal between buildings and the range/concrete may be an issue, so ideally I'd put the antenna behind wood outside.

If it is possible to put the antenna on a cable, does anyone know where I can find a suitably terminated cable for sale and what to ask for?

Re: Can I locate the RF antenna away from the emonTx?

Submitted by JD on Thu, 08/10/2015 - 20:32.

I bought a few cheap ebay 433mhz antennas to try, and they all are no better than the stock antenna (or even a wire). But, getting the antenna on the other side of a wall or out of a metal cabinet can make a big difference. This one was cheap and OK:

http://www.ebay.com/itm/GSM-GPRS-Antenna-433Mhz-3dbi-cable-SMA-male-Magn...

Re: Can I locate the RF antenna away from the emonTx?

Submitted by Bill Thomson on Thu, 08/10/2015 - 22:26.

I bought a few cheap ebay 433mhz antennas to try, and they all are no better than the stock antenna (or even a wire).

Hi JD,

Did you mount your "ebay" antennas on a ground plane?

Here's a couple of pics and some info.

Re: Can I locate the RF antenna away from the emonTx?

Submitted by Bill Thomson on Thu, 08/10/2015 - 22:37.

If it is possible to put the antenna on a cable,

Yes.

One thing to keep in mind is to keep the cable length as short as possible. Losses in the cable affect the level of the transmitted and received signal. The longer the cable is, the more it will reduce the signal levels.

does anyone know where I can find a suitably terminated cable for sale and what to ask for?

The thread I linked to in the post above this one, has a link in it for a source of ready made RF cable assemblies.

Re: Can I locate the RF antenna away from the emonTx?

Submitted by crispin on Thu, 08/10/2015 - 22:51.

Thanks! So if I understand right I'll be looking for RG-174 cable with male and female SMA connectors? Looks like there's a 6' cable of that kind on amazon. Hopefully I can probably poke that out under the eaves with the antenna on the end so the emonpi in the other building will get a signal.

Re: Can I locate the RF antenna away from the emonTx?

Submitted by Bill Thomson on Fri, 09/10/2015 - 10:49.

So if I understand right I'll be looking for RG-174 cable with male and female SMA connectors?

Correct.

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