Antenna help needed

I have access to a couple of rather large antennas, but they are labeled as 900-935 MHz. Is there any chance that they might work at 2.4 GHz? Would modifications be required? I haven’t been able to get the antennas out of their boxes to see what they actually look like. If there’s a chance they could work, I might be able to get them out of the shipping cylinders.

@wgbartley, those are tuned as per the labelled frequencies meaning impedance as well. There is no simple way to modify them for 2.4GHz. They would be great for zigbee or the Flutter units!

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If I could get my hands on a couple of Flutter units… Hrmm.

they don’t actually exist do they - think they got funded but never delivered.

We met the creator and saw the units working! He will be fulfilling the pledges very soon then sell them online for $29. A steal if you ask me!

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ah great, well if they really do manage the 1km range they say (unlike rf24/433’s claims of 100 metres that is more like 20m) then they should be good. cheaper than xbee and competitive with ciseco

@sej7278, according to the creator, he tested them to 1 km without any problems (outdoor, line of sight) and he says they should be able to go to 3 km. Definitely a good deal WITH a processor onboard, crypto and huge range!


Do you have the contact? He only sold within US but I would love to get a pair and have fun and maybe integrate with the cores :slight_smile:

Otherwise I can ask @zach about the flutter wireless :smiley:

@kennethlimcp, here is the Kickstarter link. Click on “contact me” and that should do it. :smile:

He says in his last update:

and are now working to put a small store on our site to take more orders before our first manufacturing run so we can get the best volume discounts.

So there is a chance to pre-order I suspect.

So I was pretty sure based on the range, but it took me a long time to find where it says on their site that Flutter is 915MHz ISM band device. So legally that is a ITU region 2-only device, so sorry Kenneth. The ISM band rules are that you have to limit tx power and accept all interference, so the range is a bit of random variable. There are plusses and minuses to any frequency band these days, I guess.

You can get a $12 module at Sparkfun that transmits at +20dBm, which would likely get you 250meters. He must be using spread-spectrum or some other digital modulation technique to get to 1km. The max tx power in that band is spec’ed as an electric field a certain distance from the the antenna (EIRP), not a power level, so modulation matters. I see some folks have transmitters doing +36dBm tx in that band with digital modulation.

It’s a cool idea for remote sensors.

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