emonBase with 433Mhz SMA Antenna

First off I must say I was very pleased to have come across OEM in my searches for energy monitors, it's certainly the most versatile option I've seen, thank you to all who've been involved in the development.

I've recently installed solar panels and an inverter and now want an energy monitor to keep tabs ont he power usage and generation without having to manually go check my utility meter every day and compare it to the logs from the inverter.

This will hopefully be a relatively easy question, being my first question on the forums...

I don't have any OEM kit yet, still deciding what I need and will be posting a longer question later...

I'll probably get an emonBase but see that it looks like it has the simple wire antenna that will stick out a Pi case the unit would go into. I'm sure it will work just fine but I'm curious about replacing the wire antenna with the 433Mhz SMA antenna available in the shop, which states that it includes a PCB connector.

So, my question(s), is it possible and easy enough to replace the wire antenna with the SMA antenna and are there any instructions, preferably with diagrams/pictures, available to do so?

pb66's picture

Re: emonBase with 433Mhz SMA Antenna

The emonTx and the emonPi have tracks at the board edge to accommodate the external antenna's "pcb connector" so although it is most probably possible it's not quite as easily done.

The range on the rfm69pi's is pretty good with the wire alone, I have one near the centre of my "network" which the wire doesn't even need to be protruding the Pi's case it is just looped (lightly coiled inside the case, the short wire isn't even quite long enough to do 1 full lap of the inside). I also have another at the far outskirts of the network and I have added a 2nd wire as a ground dipole and that has improved the range to comfortably read the nodes it originally struggled with, again both these wires are loosely looped rather than fully extended, so you may not need the external antenna, if you can comfortably receive your nodes without the antenna, adding it may just pull in more noise.

By all means if you need greater range try adding the external ant, but if you are considering adding the antenna because you dislike the idea or the appearance of the wire, I would say try tucking it in first as no (visible) wire or antenna is even easier on the eye.

Paul

Rhys's picture

Re: emonBase with 433Mhz SMA Antenna

Hi Paul,

Thank you for the reply, I think I'll go with your suggestion. It was partially about the looks but mainly about the range but I've found other posts mentioning range and I think I should be fine. The only potential extra range interference may be the server cabinet I'll probably be placing the emonBase in but if it proves to be an issue I'll just place it on top of the cabinet and just run slightly longer LAN and USB power cables so no real biggy...

Rhys

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