Szhuashi LoRa Bi-Directional Amplifier
The Szhuashi 20 watt LoRa amplifier is nothing short of amazing for use in Mesh / LoRa applications.
If your mesh firmware has extremely short duty cycles (like ChatterBox), this thing doesn’t even get warm running 24/7.
It doesn’t use much current and can easily be powered by a 24v battery
Usage requires an amateur radio license in the US
About This LoRa Amplifier
Specs
Cost (2025): $219.00 (Ebay)
Frequency: 800MHz-930MHz
Output Power: 43dBm (20W)
Gain: 18 dB RX, 18 dB TX
Indicator LEDs: Red = Power, Green = Activity
What’s Included
Amp (Mountable aluminum enclosure)
No power supply included
No instructions/paperwork included
Mesh / LoRa Amp Testing
Methodology
As a mesh communication firmware developer, my only interest is really whether this amp plays well with LoRa mesh applications. My testing is pragmatic and focuses on reliability of encrypted mesh deliveries (one way and 2 way) at various distances, and that is really all.
As you can see in the screenshots below, using the ChatterBox mesh firmware, I’m able to see a live view of which devices/nodes I’m receiving pings from. I’m also able to send messages, which return an ECDSA signed confirmation (shows as check mark), so I know for a fact the message was received and validated, without seeing the distant device.
My “Base Station” (basically a node)
All tests with different antennas and distances were done by viewing signal strength, attempting direct messages and broadcasts, and receiving direct messages/broadcasts from my fixed position base station. The base station is not really what I’m testing here, but rather what this 1 watt amp can is capable of. This base station isn’t the subject of these tests, but since it’s involved, I’m showing it here. It’s composed of a ChatterBox E-Paper Mesh Node, 20 watt amp, and 84” roof mounted omni antenna.
The Test Unit
For the test unit, I simply paired a ChatterBox E-Paper T3S3 node with the Szhuashi LoRa amp and a 24v LiPo battery to power the amp (and keep the node charged).
I put all that into an easy-to-transport enclosure, and left the antenna connector accessible where I could easily swap the aforementioned antennas at various locations.
Antennas
Base Station Antenna
The “base station” (node) is common across all tests. I try various antennas, as shown below, paired with the Szuashi 20 Watt LoRa antenna to compare how well the amp works with the firmware and antenna combo.
This node is generally what I do distance tests with for simplicity.
It’s running with an 84” Signal Plus Omni antenna (source: Amazon).
Laird Phantom Stealth
A very stealthy option (you can barely see it mounted on my car), but very good performer.
This is a great option for car-mounted antennas. They’re so stealthy, I can’t find any sources that have them in stock currently.
Signal Plus 15” Omni
These are great antennas for mounting to a wall or mast, while not being overly large.
They are weatherproof and extremely dependable performers for LoRa / mesh.
They come with cable and usually an SMA adapter. You can find them on Amazon for $30-40.
Signal Plus Yagi
This is another great outdoor antenna for mounting to a mast, while not being overly large.
It’s directional with a focused 48° horizontal beam width.
They come with cable and usually an SMA adapter. You can find them on Amazon for $69.
Results
The results of the Sunhans LoRa amplifier’s connectivity to the base station at varying distances are shown below.
As you can see, all pairs are generally able to receive encrypted/signed messages quite well all the way up to 25 miles, depending on your antenna (and of course your location/height/barriers/etc).
I was quite surprised with the good results from the Laird, given it’s so small and unnoticeable.
These tests were done on flat land in the midwest, before trees had bloomed in the spring. I have not tried longer distances yet.
If you were to repeat these tests where the node (or you) is positioned on a place with high visibility, such as a mountain top, I think you’d be able to do much better than the results show here. I would not be surprised doubling the distance in that case.
One of the main benefits (here) of the amp is penetration of obstructions. Given earth curvature, I’m not even sure how I was getting good connectivity at 25 miles, but I certainly was.
The packets/pings/etc that are sent get back an instant ack packet, have an expiry, encryption, hash/signatures..there is simply no way any RF could be mistaken for a ChatterBox packet or message.
After the message is sent, the recipient device sends back a unique and signed confirmation of receipt, which again..it’s unmistakable and unfakeable, so I’m quite confident in these results.
Conclusion : Excellent LoRa Amp for Secure Mesh Comms!
When paired with a suitable antenna and LoRa mesh firmware that that has robust delivery capabilities, you are probably going to be blown away by the results you get from this amp.
I’ve bought several of these from the source linked earlier (ebay) and the quality has been very good on each one.
The seller linked has also been good to work with. I typically receive the units 2-3 weeks after ordering.