I have some NRF24L01+PA+LNA modules and am going to make a sort of modified version of a ship to shore radio. Basically, there is two transceivers, one on land, one on a sailing dinghy. They can communicate voice almost like a walkie talkie from one to another. Because it is on a sailboat, I need quite a bit of range. I would like the range to be at least a mile (1,610 meters).
Does anyone know how to get more range out of these modules? I looked it up online and came up with a few things:
Add RF shielding by using aluminum foil
change the data rate to 250kbps (which might not work though for voice)
change the channel to a higher one, because wifi and bluetooth mostly use the lower channels
build a directional antenna (which might not work either, because a boat is a moving object)
plenty of filtering on the power supply with capacitors
Well, if you are really into building antennas. High gain, omni-directional antennas can certainly be constructed. Look for coaxial collinear antennas and other types of vertical antennas.
An antenna can be just a metal (copper) wire. You may use the metal wires that keep your mast upright as a ground plane. Then at the top of your mast you could add the antenna. At 2.4 GHz it will be quite small (lambda 12 cm).
At 2.4 GHz a direct line of sight is very important. Therefore the higher the antenna the better.
Acc. to wiki a height of 1.7m should give you 3 miles.
But that is without any waves. And your antenna would be in between the metal wires that keep your mast upright. That will hinder transmissions in certain directions (where the wires are).
My boat is only a 8' sailing dinghy. It's so small it doesn't even have any stays or standing rigging (metal wires to support the mast)! The mast is aluminum though and ~14 feet tall.
You mean all the antenna has to be is a specific length of stripped copper wire?
Then the alu mast will be your ground plane.
You may indeed cut a copper wire to the correct length for your frequency.
I have been broadcasting at 3m, so not experienced in 2.4 GHz. Maybe someone else can help you out as you need to take into account the impedance that your circuit is expecting, the correct type of cable and probably more. But I have read articles on cheap antennas made from just a copper wire. So maybe just google cheap 2.4 GHz antenna...
Maybe you like this : https://pin.it/5Le6OTd.
This antenna will direct your signal.
This will increase your reach .
Maybe not very handy on your ship, but might work from the land side.
The main problem is these devices don't have great signal/noise performance, limited range of baud rates and run in the microwave region (2.4GHz) so antennas are typically low gain (have a small effective area). For voice you maybe want 8kHz uLaw sampling, ie about 64kbaud, considerable less bandwidth than the nRF24L01+'s minimum 250kbaud. Power required (for given range & SNR) scales with bandwidth, so chosing a Mbaud transceiver makes no sense.
If you want range go for a lower carrier frequency where the antenna can be larger.
You also need antena height - if the boat doesn't have rigging, the shore station will need considerable elevation to compensate.
Unfortunately there is little legal frequencies where you may transmit without license...
But indeed, at 2m you can do tens of kilometers with a few watts.
Yes, you would need to direct it.
From the land to the boat and from the boat to the land (if you have 2 such antennas).
On the boat you would need something to keep it horizontal. Otherwise your antenna will point into the waves or into space depending on wind an waves...
