RF Range Extender

Firmware/software/electronics
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Surrender
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RF Range Extender

Post by Surrender »

Good morning,

I've just thought about how to amplify the RF to get a extended range. After a couple of minutes i found this nice IC from Texas Instruments:
Here a overview: Overview CC2590/CC2591
And here the Datasheet TI CC2590.

The chip costs ~2.3$, on this site you can buy 10 pieces for 23$ with free shipping: AliExpress CC2590 QFN16

Maybe someone can look at these documents and check if this is possible to use with our crazyradio to get a extended range. It consumes about 22mA @ 12dBm, max: Up to +14-dBm (25mW) Output Power.
The receive sensibility is also extended up to +6dB.

There is also another type (from Microchip): SST12LP07
and here one from MAXIM:MAX2242
I'm not able to find someone who sold max2242 or 2240.

So i searched a HF Amplifier @ farnell.com and found this:
Farnell Page ALM-2812
ALM-2812 Datasheet for 1,8€

Greetings
tobias
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Re: RF Range Extender

Post by tobias »

Good afternoon Surrender!
I did some investigations about this a while ago as well and from what I recall there where something not so good about the CC2590. I think it was related to noise.

I've seen a couple of 2.4GHz amplifiers that could easily be connected between the Crazyradio and the antenna which would be the simplest solution. There is still the problem with the down-link though and putting an amplifier on the Crazyflie is more or less impossible without redoing it.

In cases where a up-link is sufficient, just sending control data, there are software improvements that can be done such as channel hopping and I would expect switching to a "up-link only mode" would increase the range alone.
Surrender
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Re: RF Range Extender

Post by Surrender »

Thanks for your reply! :)

Yes, i also read about it (4,6dB LNA or noise or something). I dropped the idea with this chip anyway.

The MAX2242 would be a nice thing (i think as a company you can buy it), maybe a nice addition to a next crazyflie board release. It has a size of only ~2x2mm which is very small.

I most like the ALM-2812 because everything is in the chip (matched in,output, ~3x3mm size), only one capacitor is needed in addition. This one can be added on the crazyradio and on the crazyflie to get a really good extended range (duplex).

What i want (and what maybe others also do) is to get a better uplink. It does not really matter if the CF is not sending data anymore to the base station, but it matters if the CF can receive commands even if its far away. The RF AMP implemented in the crazyflie board will be cool but the we need (as you say) a new board or a small hack (mini board as extension).
tobias
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Re: RF Range Extender

Post by tobias »

Thanks for the links! Might be possible to fit one of these amplifier on the board if switching to a balun filter :).

Arnaud is looking into the channel hopping and "up-link only" software but he also has the least time. If you are up for it... ;)
Surrender
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Re: RF Range Extender

Post by Surrender »

Yes, maybe they fits to the board. :D

I also have not that much time, but maybe when i have finished the "find me" - mode and the flight duration calculation then i can have look into a "up-link" - mode for the pc client and the channel hopping support (don't know much about channel hopping). :lol:

Thanks for looking into and checking if it is possible to add a amplifier.
tobias
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Re: RF Range Extender

Post by tobias »

One of these external amplifiers should give a pretty good range in a up-link only mode. They are probably not leagal to use though...
foosel
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Re: RF Range Extender

Post by foosel »

... at least not without a ham radio license. Maybe it's time to look into that again...
Image
Also: AR.Drone 2.0 (RC-enabled thanks to self-soldered MiruMod) and Hubsan X4 H107
Surrender
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Re: RF Range Extender

Post by Surrender »

1000mW is ... too much for our small fly. We need a FPV system, otherwise 50 - 100mW are enough to get a good range, but i cannot find a external amplifier for 100mW or similar..
Surrender
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Re: RF Range Extender

Post by Surrender »

Moin,

last week i received two different antennas for the crazyradio.
One with 5dBi and one ith 8dBi. I like the 5dBi because it is smaller and has a foot to stand on. Now when flying outside it is much more smoother, less interference and a better link quality. I didn't test the range but i think its now much more better.

Links to products:
5dBi TP-Link-TL-ANT2405C
8dBi TP-Link-TL-ANT2408CL

(both are from the german amazon page, sorry if it is not in english)
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