HC12 Range Issue

Hi all,

I’m using HC12 modules to create wireless transmission of sensor data. According to datasheet it provided 1.8KM in open space(FU4 mode). I tried all possible combination the max distance i get is about 210meters(without data loss) and 260meters(with data loss).Still not tested in complete open ground.

The other thing i observed is I’m getting almost same distance in FU3(4800baud rate) and in FU4 mode(1200baud rate). Changing antenna from spring to SMA also dosn’t making any difference.

Few things i need to know,
1)What Max HC12 transceiver range can be obtained in FU4 mode and FU3 Mode without any data loss!?
2)Do i making any mistake in doing testing like type of antenna, delay between data transmission(i’m giving 1s) or the place of testing(i tested in Residential Area) !?

The distance between good line of sight (hilltop to hilltop for instance) and what you get on the ground (in a residential\urban area can be very significant. So the distance your getting might be normal.

The spring antennas are fairly inefficient, so a proper antenna should make quite a differance, a 17cm bit of wire for 434Mhz ought to be significantly better.

SMA is a socket type, its meaningless to use it to describe what type of antenna you have, an antenna with an SMA plug\socket on it could be any old bit of junk.

This might provide some pointers;

Reception Distances at UHF my 1000:1 rule

Thank you for your Suggestion,it cleared most of my doubts.I will do range test using 17cm wire antenna and am really curious to see the Results.

Thanks and Regards,
Chandan.

I have tested FSK style tranceivers similar to the HC12 extensivly in the urban area by me, where there are houses in the way between TX and RX.

The range I get at ground level with handhelds, for data packets @ 1000bps @ 100mW would be around 300m maximum.

The same setup was good for 40km between hilltops.

Such are the very large distance differences between urban areas and good line of sight.

Thank you once again for your suggestion, i tried with 17cm antenna and i got 50meters more than previous result. Need to check on Hill top.

I have few questions,
1)40Km which you got is using Arduino or any Development KIT!?
2)Is there any module other than HC12 where i can get long range communication using Arduino!?

Thanks And regards,
Chandan

1)40Km which you got is using Arduino or any Development KIT!?

The processor used was in that case a PICAXE. The processor used has no affect at all on the sensitivity and distances of the RF device of course.

2)Is there any module other than HC12 where i can get long range communication using Arduino!?

Indeed there is. I repeated the 40km hilltop test with LoRa devices a couple of years later, they covered the same distance with a mere 3mW versus the 100mW needed by the FSK device.

The current one way record for a LoRa device is 702km;

Record 702km

If anyone can spare me £25,000 it would fund a small satellite launch, and I estimate you could receive LoRa packets on a Arduino UNO based handheld receiver at 2000km+.

We just reached 2.2 KM with the spring antenna.
BUT, not all HC-12 modules are good. See this video:

chandu_csg:
Hi all,

I'm using HC12 modules to create wireless transmission of sensor data. According to datasheet it provided 1.8KM in open space(FU4 mode). I tried all possible combination the max distance i get is about 210meters(without data loss) and 260meters(with data loss).Still not tested in complete open ground.

The other thing i observed is I'm getting almost same distance in FU3(4800baud rate) and in FU4 mode(1200baud rate). Changing antenna from spring to SMA also dosn't making any difference.

Few things i need to know,
1)What Max HC12 transceiver range can be obtained in FU4 mode and FU3 Mode without any data loss!?
2)Do i making any mistake in doing testing like type of antenna, delay between data transmission(i'm giving 1s) or the place of testing(i tested in Residential Area) !?

Looks like there are faulty clones out there. My modules had a horrible range and could not penetrate a single wall with the spring antenna. After I applied a fix the module could penetrate at least 3-4 concrete Walls with the spring antenna.

Somebody found a way to fix those faulty modules. Helmut Jahrstorfer on Amazon.de has written, that those boards have a missing trace on the board. He says, that 3.3V must be measured at a specific point. If not, you have to manually add a connection between two resistors.

See picture in my comment in https://www.instructables.com/id/HC-12-Distance-Problems/.

every time I see a picture of an HC-12 with a spring antenna and poor range the board is upright and the antenna is horizontal. the receiving antenna is vertical. that can't work. the antennas have to be parallel to each other. vertical antennas are inherently parallel, horizontal antennas must be aligned parallel.

horizontal here and vertical there is inherently a weak rf connection. it's called polarity.