Fiberglass antenna

Development Hardware
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Good morning people :slight_smile:
Does anyone know how long a fiberglass antenna can last outdoors? Is there a cheaper alternative?

Is there any negative effect in having a repeater/node with one of those and a 1W lora module?
Thanks :slight_smile:

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A fiberglass antenna can last from 1 year to 10 years depending on the environment.

Vibration from the wind and the mounting placement is one factor, Water and ice is another.

UV radiation is usually ok :blush:

The cheapest alternative is to make a dipole antenna.

The antenna dbi and the power depends off the purpose and placement.

If you place the unit on a high mountain top with a antenna with very high gain and radio at max power to get radio cover down the valley. The result is not ideal.

Antenna gain, power and placement all need to match the purpose.

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I understand, so it would last a long time, depending on the weather ^^

What do you think about this antenna? (I’m in no way related to the vendor)

According to this wiki the ttgo tbeam radio delivers +20dBm
https://tinymicros.com/wiki/TTGO_T-Beam

I would love to put a node in a neighborhood, not on a mountain.
Would this equipment be a good match?

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Some thoughts about the antenna :blush:

  • I do not know what region you are in, but if you will use 868 MHz this is not a good match.

  • If you are in USA or Canada, its better match. ( not perfect )

  • The radiation pattern to the antenna is not known so hard to tell from the picture.

  • If this is made like a dipole you do not need to think about RF ground. If you need to provide RF ground yourself, you need to plan where to mount it. Wood and bricks is no good RF ground.

  • +20 dBm is 100mW and the antenna is rated for 50 000mW so that’s inside the limit :wink:

Speed of transmission:

  • Im not sure about the sensitivity you like to use but lets say it is -130 dBm. The transmit power is +20dBm and we have a link budget of -110 dBm

Free Space Path Loss:

  • 40 Kilometers distance and frequency 868 Mhz with a 8 dBi TX antenna and 8dBi RX antenna is ca 107.25 dB loss I “air” ( That’s not with loss in cable and connectors )

Then we have 2.75dBm to play with

Things to check:

  • Losses in cable and connectors you must take into calculation.

  • EIRP will be 20 DBm + 8 DBi = ca 631mW so check your local regulation

Its very hard to say if this is a good antenna for you or not, but you got some information to dig into.

40 000 meters around your house are also in the upper part of “neighborhood”. Do you really need that range :wink:?

Maybe a standard 2dbi antenna will do the job :tokyo_tower:

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I understand, so a node can communicate with that antenna without having a similar one?

Ground? Of course it must be put on a mast but I must also connect a ground wire for lightning, am I right?

The connector would only be a sma to n male :slight_smile:

Haha I would love a few hundred meters higher to communicate with a lora repeater satellite, I don’t know, one can dream haha (also at some point we could collect money and send a small lora meshtastic repeater to space) :satellite: :artificial_satellite:

Thanks for all the technical information, I don’t think an antenna like that would fit in a mesh project, I just saw some similar antennas in european countries and I thought they would also work for meshtastic :slight_smile:

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I’m not sure what you are asking, but you don’t need similar antennas of all units. Portable units may use small antennas… Car maybe like magnetic antenna and repeaters may like dipole or ground plane antennas.

You have signal ground and equipment ground… and sometimes this is common. :slight_smile:

Ground wire for lightning protection is a hole other story.

This antenna radiation pattern probably does not radiate with a high angle. That is a different antenna design. If your goal is space, you cannot use this antenna. This antenna will probably radiate in a very narrow pattern over ground.

The antenna has to match the purpose. If you like to have a narrow beam angle, low power transmission (save battery power) and week signal reception ( save power at transmitting node ) it’s a perfect match. ( If you manage to get a low SWR at your frequency )

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I think it’s all clearer now, obviously I need to do more research on antennas.
Thanks for your answer :slight_smile:

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I’d be careful with the 1 watt radios. A lot of other systems use the same frequencies and a strong transmitter can drown out other users. You don’t want the electric company knocking on your door because they stopped getting readings from the meters near your node.

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You’re right, I don’t want to bother anyone ^^