Hello! I am following the meshtastic project for a while, and now I found some boards that I want to buy but I’m not 100% sure they are compatible. The sellers on Aliexpress do a pretty terrible job on adding all the important information about the board and the specific versions (I saw that are a couple different ones for sale). Maybe somebody here bought this ones or they recognize the specific version from the photos and could confirm they are compatible.
My second question would be about the antenna. Is the one that comes with it good enough? Knowing that shipping could take over 2 months, I would prefer to also order some better antennas at the same time. It would be great if you would give me some suggestion for these ( I will use the 868Mhz board version).
Also, if this works well, I’m thinking about adding an antenna on the top of the house or on a higher place so I would need a more robust antenna for this. Would an extension cable work? The device would probably be way safer inside with just the antenna outside and an extension between them. I live in a city and I’m planning to use this with a friend that is about 700m away but there are some buildings between us so placing the antenna as high as possible may be the only way we can get this to work.
Any response and suggestion is appreciated. Thank you very much!
Link to the board set
Hi Sebastian and welcome. The boards that you have linked to are the Lora V1 boards by Lilygo. They will work, just be sure to use the correct firmware with them. See LILYGO® TTGO Lora devices | Meshtastic
In terms of antennas, the ones that come with the devices are usually just about adequate, but could be better. I can’t give any particular recommendations as I got mine from a company in the UK. When adding an antenna to your roof, you are likely better putting the node outside in a waterproof box. Cable can significantly lessen the transmission power. See - Times Microwave for more information on cable attenuation.
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Welcome @sebastianhamza
@apt105 Is correct.
Any inexpensive antenna is going to be a bit of a gamble, or luck of the draw due to how finnicky antennas can be, and the tight manufacturing tolerances.
Quality antennas have a premium cost because the designers and manufactures focus on accurate products, not cheaply mass produced.
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Thank you!
That cable attenuation calculator is great. Turns out that the cable length that I had in mind would be less than 50% efficient so that will probably be worst than just keeping the antenna on the balcony. If the wifi of the board will be powerful enough, I could probably find some waterproof case and place the entire thing on the roof.
That makes sense. I saw a youtube video of someone with a frequency analyzer that tested cheap antenna models and some turned out to be almost unusable. I will probably just wait for the first 2 boards to arrive and test those. Depending on what results I get I will invest in some better antennas or some additional nodes to boost the range.
Thank you!
That is a beautiful QFH antenna. Unfortunately a circular polarized antenna is going to degrade your reception in this case…unless all your nodes use circular polarized antennas.
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This is very true for fixed sites using antennas with the same polarization.
Mobile devices that are not mounted on cars where the antenna has a fixed orientation to the ground plane and similar orientation to other fixed antennas could do about as well or better with a H/V antenna Rx/Tx to a Cir Antenna due to the often changing orientation of the mobile antenna.
GPS satellites use circular polarized antennas for a number of reasons, but cheep gps receivers often have a H/V antenna.
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Yes I guess the “node in your backpack at some random orientation” could benefit.
If I remember correctly, the attenuation to a H or V polarized antenna from a circular is -3dB either way.
I believe that is correct.
Also one thing I’ve found in my reading about antenna polarization is that RFID applications often use semi-directional circularly polarized antennas/