Here’s my modded gateway with it’s discrete extra heatsink.
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Anyone using RAK 2245 for some time now? How stable is it?
Had my RAK2245 up for maybe 4~5 months solid running in my server rack in the garage connected to an external antenna on AU915 here in Australia, no problems yet.
I may need to look into enlarging the heatsink shortly before our summer hits though.
I started this week building my own RAK2245 gateway. Completely new to this topic.
It is not in an enclosure for the moment open in a room that has a temperature of about 16. But the heat-sink is very hot. 45-50 degrees C
It is on top of a Raspberry pie 4, I have a passive cooling.
The range seems to be disappointing, but I live in a city surrounded by buildings and my double glass window may block some signal.
It definitely needs an active cooling in my opinion.
That is about normal for gateway concentrator boards. Without heat-sink the chips will run to over 70C.
You could attempt to mount a huge (PC CPU type) heat-sink without fan on the existing heat-sink, that should keep temperatures lower.
Why did I not think about that?
I have here a PC that dropped dead with a HUUGE heatsink on it!
I can receive uplinks from about 1.5km+, however when it comes to downlink messages I can receive them from max 500 meters. I thought that downlink messages will be no problem since US region has 500kHz bandwidth for downlinks, SF is set to 10 and Tx power to 20dBm. Sensor has same params except bandwidth is only 125kHz. I’m using 915 MHz US version. Does anyone have similar issue?
I added an external antenna to mine (Australia - old cellular type, as our frequency’s here use part of old defunct cellular ones), which made all the difference - I bought a new antenna a month or so back which it tuned for 915~928mhz which should filter out all the frequency’s not needed and be better again, but haven’t had time to put it up yet. I also just have the pi sitting on a shelf next to my rack being passively cooled as well.
This is the one I have to put up when I get time https://zcg.com.au/d/CMG920-6/
That’s not how an antenna works.
Hopefully the antenna would work well in terms of gain and SWR when transmitting across the specified frequency range. How it works outside that is not specified - typically the performance degrades.
But antennas are generally specified in terms of how they handle desired signals, not what they do with undesired ones. Unless there’s a bad connection causing rectification, handling undesired energy is really the job the the receiver’s front end, not the antenna.
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Yes you are correct, my radio will no longer have to filter out as much undesired noise.
No, that is really not true
I’ll ask for a refund on my new antenna then. Doesn’t seem like it will be worth the hassle of installation if the existing 850-2100mhz one will be suffice. I was always worried for potential noise as 850-914 is used by a mobile carrier here.
The new antenna may well be better, but in terms of putting the transmitter energy out onto the air, rather than bouncing it back up the cable where it will heat up the power amplifier.
Hi, which mpcie formfactor concentrator would you recommend then?
If you are referring to this:
When considering RAK2247 with Linux PC, keep in mind that uses code discontinued by Semtech in 2015. Semtech discontinued the code with good reason (timing inaccuracies due to the USB to SPI translation which cause scalability issues)
Then it’s important to note that the RAK2247 comes in both SPI and USB versions, and the concern mentioned there is specific to the USB version which someone would probably pick if they had a Linux “PC” vs. a Linux “embedded board” likely to have an SPI channel.
If you can use SPI, be sure you order the SPI version of the RAK2247. Unlike the RAK833 where the USB model also supported SPI, for the 2247 you have to specifically chose the SPI version at order time. You do have to slow the clock speed to account for a poorly chosen and unnecessary level translator in the 2247, but that doesn’t really cause problems the way the latency of an FT2232 USB interface does.
If you need to use a USB interface because your host system is constrained, pick a “pico GW” design which uses an MCU to accomplish the tighter timing tasks. nFuse makes them, one of the Heltec offerings might also have this capability but you’d have to check carefully. The picoGW code from Semtech code forces slightly longer timings than the native SPI code, but not by much. Also note that it is unfortunately a different packet forwarder codebase (though if you do a full diff, not terribly different), so if you want to use a packet forwarder that has been modified from the Semtech original, you may need to spend some time patching before it will work with the pico GW interface code.
Yes, I was referring to that statement. I want to use it in an alix apu2 ( https://www.pcengines.ch/apu2.htm ) no mention in the docs ( https://github.com/pcengines/apu2-documentation/blob/master/docs/APU_mPCIe_capabilities.md ) about SPI support though.
Was planning on using https://github.com/RAKWireless/rak_common_for_gateway
Was planning on using GitHub - RAKWireless/rak_common_for_gateway
That’s precisely what is not recommended, as the USB latency really limits agility on a busier network
For picoGW solutions which are sensible I should also mention that the nFuse seems to have compatibility issues with some internal mPCIe slots. You might consider it, but in an external holder connected to a USB port.
Even if I use the SPI version? I understand the USB version has timing issues.
https://github.com/RAKWireless/rak_common_for_gateway states:
“Added support for rak2247/rak833 spi version.”
Am considering: https://store.rakwireless.com/products/rak2247-lorawan-gateway-concentrator-module?variant=29444341923885 (SPI, not USB)
It’s unlikely your embedded PC supports SPI. Certainly not on the mPCIe connector - there isn’t even a standard pinout for that, because SPI is not part of the mPCIe spec the way that USB is.