Hi, I'm working on a PCB for my project where I use esp32, LoRa and GPS.
The problem is that I'm weary space limited and I have to put them next to each other as shows the picture.
Will the antennas interfere with each other or I can put them even closer?
I'm not really planning to use Bluetooth too much and I won't be using wifi.
Thanks for help.
That's hard to say. Place the devices that close and test!
I can't really test it so... thanks for the help anyway.
I dont see why you cannot test it.
The main issue would be the GPS and its relativly poor antenna, both the ESP32 and the LoRa device could interefe (as in affect reception) of the GPS.
Whether that is an problem rather depends on the application.
Its not clear what the three antennas actually are - there's some sort of coax connection - so one
antenna is off-board anyway?
2.4 ghz, 432 mhz?, and 1.2 - 1.6 ghz
if the LoRa and GPS add up to 2.4 ghz, you may have a problem.
So I can see it...
I'm not sure how you think anyone can comment on the RF from this drawing. I see a bunch of chips, the ESP module, some connector and an SMA footprint. You need to provide a lot more detail, but I'll make a guess. The SMA is far too close to the wifi antenna. The SMA can only be Lora or GPS... where is the other antenna? If it's U6, then you do have things far too close together. You will definitely have strong cross interference between all 3.
Ok so these are the antennas I'm planning to use:
GPS - GPS1003 Rainsun microwave Tech | C239243 - LCSC Electronics
LoRa - TX433-JW-5 ZIISOR | C454883 - LCSC Electronics
Thenks for the help
...and... which one is U6? If you can completely disable BT when you're not using it, you might get away with this. You say you're space limited but do you really have to have all the RF on one side? Can you not at least rotate the ESP32 so the antenna is on the other side of the board?
U6 is the footprint one of those ceramic stick antennas, somtimes used for GPSs, OK if reception is good. It is right next to U5, which looks like the footprint of a Ublox Max8Q or Quectel L70/L76 GPS.
MK1 is the footprint of a RFM98 style LoRa device and its antenna pin is connected to the RF1 (SMA) footprint centre.
In general you would want to keep the GPS and LoRa antennas as far apart as possible, but it depends on the application, which @clip16 has not revealed.
@srnet you are correct.
I'm making a computer for my rockets the problem at the bottom I have high current stuff (voltage regulators, pyro MOSFETs for parachute charge, servo connectors, piezo) so I cant put it there.
I cant put LoRa antenna (RF1, MK1) to the side as I have no space there I might end up using spring antenna as it is lighter.
I cant rotate the ESP32 (CPU1) - it would be impossible to trace.
So the only thing I can move is GPS (U5/6) but a read somewhere that GPS antennas are spouse to be facing the sky so should I move/rotate it?
Thanks for the help
Here is a link for the project: https://easyeda.com/Cassiopeia-space-program/cfc-mark-iii
Ah, a rocket.
How fast will the rocket be going, most GPSs will stop working when the vertical speed exceeds 100m/sec ?
How critical is weight, and extra 4g or so would get you a GPS with a decent antenna ?
Is the LoRa for telemetry whilst the rocket is moving or to find it when its lost ?
What is the body of your rocket made of? Real rockets use antennas that are on the surface of the rocket. They can be "slot" antennas or similar design. Same with antennas on high speed aircraft.
Paul
srnet:
most GPSs will stop working when the vertical speed exceeds 100m/sec
Oh, I haven't think of that. That might be a problem ill probably solve it in the future I'm not planning to go super fast at the start but max 100m/s is bit low, is there an "easy" way to solve this? LoRa has +-2km max range anyway so ill might have to make a new rocket computer at a point where I would go faster.
+4g is not a big problem but I dot know which antenna in a low price range to chose.
LoRa is going to be used for both for communication while moving no big data transmission + after landing I now that LoRa is not the best but for me Radio communication is a bit of a black magic so I'm clueless what to use.
I noticed you made a satellite how have you solved communication problem I couldn't find much information about this topic?
Paul_KD7HB:
What is the body of your rocket made of?
the tube is made from PLA reinforced using resin. I could cut a hole in it for the antenna but then it would have to be a wire one are there some wire ones that I could use?
What about this one for GPS:
or
And this for LoRa if it even works with LoRa I really don't know I just know to look for 50ohm and 433Mhz
Thanks for all the help
@srnet Oh, LoRa might be the right way to do it I guess I´m just an idiot who doesn't know what he´s doing.
I searched up the $50SAT you worked on and just how? I really need to understand at least the fundamental principals how Radio communication works.
clip16:
@srnetOh, I haven't think of that. That might be a problem ill probably solve it in the future I'm not planning to go super fast at the start but max 100m/s is bit low, is there an "easy" way to solve this? LoRa has +-2km max range anyway so ill might have to make a new rocket computer at a point where I would go faster.+4g is not a big problem but I dot know which antenna in a low price range to chose.
LoRa is going to be used for both for communication while moving no big data transmission + after landing I now that LoRa is not the best but for me Radio communication is a bit of a black magic so I'm clueless what to use.
I noticed you made a satellite how have you solved communication problem I couldn't find much information about this topic?
@Paul_KD7HB
the tube is made from PLA reinforced using resin. I could cut a hole in it for the antenna but then it would have to be a wire one are there some wire ones that I could use?
What about this one for GPS:
BWGPSCNX8-8B1 BAT WIRELESS | C496567 - LCSC Electronics
or
https://lcsc.com/product-detail/New-Arrivals_BAT-WIRELESS-BWGPSCNX18-18B1_C496568.html
And this for LoRa if it even works with LoRa I really don't know I just know to look for 50ohm and 433Mhz
TX433-FPC-2906 ZIISOR | C454888 - LCSC ElectronicsThanks for all the help
Google "skeleton slot antenna". You can make a good one out of foils and glue it to the outside of the rocket. Two tiny holes to connect to the long edges of the slot.
Or you can make a dipole antenna out of foil and make two tiny holes to connect to the near ends of the dipole.
Paul
clip16:
@srnet Oh, LoRa might be the right way to do it I guess I´m just an idiot who doesn't know what he´s doing.
I searched up the $50SAT you worked on and just how? I really need to understand at least the fundamental principals how Radio communication works.
$50SAT was before the days of LoRa, making a £3 radio module that the manufacturers claimed was good for 1km operate at 1000km+ was a challenge to say the least, lots of work and testing. This Video explains the project; https://www.youtube.com/watch?v=q00Fm-ij02M
As for the rocket, the speed limits are there to prevent the use of GPS in missiles, I believe you can get licensed GPSs that will do the job, not cheap I guess.
For your tracker then just use a simple vertical wire antenna for the LoRa, no need for the SMA socket, and the same for the GPS, a wire antenna will do, better than the ceramic chip antenna too.
Simple wire antennas 1/4 wave long is the approach used in high altitude balloon trackers and LoRa has worked at up to 832km, no need to overcomplicate things, see here; https://www.thethingsnetwork.org/article/lorawan-world-record-broken-twice-in-single-experiment-1
What you probably need to be more worried about is the Lora transmitter getting into the GPS receiver and interfering with it. Your Lora probably about 900mhz and the gps about 1500mhz but that puts the second harmonic of the Lora pretty close to the gps. Your gps will have no affect on the Lora. Another thing to remember is the ceramic patch types of antennas base their published pattern and gain based on their mounting on a certain size ground plane so on a plastic rocket all bets are off about those. Personally I would be looking at antennas developed drone drone use. Larry
Here is an example of a balloon tracker for a foil party balloon, the GPS is on the top, note the simple 1\4 wave wire antenna, and the LoRa device is on the bottom, LoRa antenna is a 1/4 wave vertical wire with radials.
This was for 2.4Ghz LoRa and that balloon was tracked out to 85km, a record at the time for 2.4Ghz LoRa ......
Ok, thanks for all the help especially @srnet
I'm going to use put header pins on the board one on each side for wire antenna if I'm correct
LoRA - 868MHz = 8.2169585253456212115cm.
GPS I guess I should use the L1 band as its furthest from the LoRa band so that's 1575.42 MHz = 4.5272498762234834047cm
What time of wire do you recommend? how width should it be?
The GPS is capable of GLONASS and BDS do you know if they have the same 100m/s limitation?
Thanks for the help