Objective 

 Quartz Routers series use a combination of Router and cellular module firmware to function. Router firmware can be updated by following the application note “How to upgrade a Siretta Router Firmware Application Note” 

Updating Router Module Firmware has been a complex one that involves opening of Router casing, removing PCB assembly, detaching the Module, plugging the Module into a USB adapter to update firmware using a tool called QFLASH. A lengthy procedure requiring Siretta Technical support.  

This application note allows users to remotely update the Module inside Siretta Router Quartz series using efficient and non-invasive procedure without disassembling the unit. 

 For remote AT over IP access, the sim card inside Siretta Router must be a fixed public IP address or private fixed IP address with the VPN connection and Router must be configured locally first to accept remote access.  

 More information about IP addresses can be found from the following application note Siretta Products IP Addresses Explained Application Note  

Solution 

DFOTA – Stands for Delta Firmware Update Over-The-Air. DFOTA allows users to update Router Module firmware using cellular network. Router is set to AT over IP mode where AT command AT+QFOTADL is issued to initiate the update process and point to a location where delta firmware is stored. 

Delta firmware file can be either stored in a remote HTTPS/HTTP/ FTP server or in a local file system.  This application note covers the procedure where delta firmware file is stored in a local file system. 

Requirements  

 Siretta Quartz Series Router (for this application QUARTZ-GOLD-11-LTE (EU) was used) 

• Windows 11 Laptop with Tera Term Version 4.96 or above (Tera Term can be downloaded from the following link – Tera Term Link ). 

• Location where Delta Firmware file is stored. 

• Fixed Public IP address /Fixed Private IP address sim with the OpenVPN. 

• For this guide Private Fixed IP address of 10.188.232.13 with the OpenVPN client was used. 

• OpenVPN client setting was provided by a sim provider and installed to Windows 11 Laptop. 

Demonstration of Solution 

 Follow Router Quick Start Guide for initial Router settings. 

1. Wait for the Router to connect to the cellular network. 

1. Confirm that Router has received IP addresses (See below). 

 Note 1:

• IP address of 10.188.232.13 shown above, is the IP address that will be used to remotely access AT over IP using OpenVPN client.
• If sim card with fixed public IP address been used, then fixed public IP address will be used for AT over IP without needing to use OpenVPN client.
4. Open AT Command over Internet Protocol Router Guide
5. Follow steps 1 to 22 of the AT Command over Internet Protocol Router Guide.

Note 2:
• Local Router IP address in AT Command over Internet Protocol Router Guide is 172.168.1.1 which is different from the local Router IP address used in this guide 192.168.1.1.
• In step 12 of AT command over Internet Protocol Guide replace 172.168.1.1 with 10.188.232.13 and continue to step 22 of the guide.

6. Navigate to the AT over IP page from Router GUI to confirm that all settings are saved as shown below.

7. You have now set AT over IP.

Enabling Remote Access

8. Navigate to Administration Tab in Router GUI.
9. Select Admin Access Tab.
10. Enable Remote Access (HTTP).
11. Check “Allow Telnet Remote Access” box (see below page).

12. Click Save.
13. You will see a message displaying “The settings changed, some settings will take effect after the Router reboots”. Reboot Now
14. Click Reboot Now.
15. Wait for the Router to complete reboot cycle.

16. Navigate to Firewall tab from Router GUI.
17. Select IP/URL Filtering.
18. Allow any traffic to 10.188.232.13 and Port 5400 (see below).

19. Click OK.
20. You will see settings as below.

21. Click Save tab.
22. Wait for setting to be saved.
23. You have now configured Router to accept remote connection.
24. Confirm that laptop is connected to the OpenVPN Server (See below).
25. Below is the OpenVPN status page, showing laptop is connected to the server and assigned IP.

26. Use laptop connected to the OpenVPN to launch Tera Term Window (See below).

27. Select “TCP/IP “radio button.
28. In host field type IP address of “10.188.232.13” (Private IP address of the sim card inside Router).
29. Select “Other” in a service field.
30. Enter port number of “5400” in TCP port#: field
31. Select “IPV4” from IP version drop down menu.
32. Once all details are filled, settings will look like one below.

33. Click OK.
34. You will be presented with Tera Term window below.

35. You have now established connection with the cellular module inside the Router using fixed private IP address and VPN.
36. Issue the following AT commands to query modem before DFOTA process.
37. Issue AT– to Check AT communication.

38. Receive OK if there is communication between PC and Module inside Router else contact support@siretta.com
39. Issue AT+QGMR to receive full current firmware version.

40. Full current firmware version is EC25EUXGAR08A15M1G_20.200.20.200

Delta Firmware location

41. From Laptop / your PC file explorer Locate path for Delta Firmware package location.
42. For this guide the firmware file is located at C:\Users\Omari Hussein\Downloads\ dfota1.zip.
43. Issue the following at command AT+QFUPL=”dfota1.zip”,14026912,500 to prepare module to accept firmware file with size of 14026912 bytes and timeout of 500.
44. Receive “CONNECT” when successful.

45. Click file.
46. Select Send File.
47. You will receive Tera Term: Send File (See below).

48. Search firmware file name “dfota1.zip” and select it.
49. Select “Binary” check box.

50. Click open tab.
51. File will be sent to the module with displayed progress bar as seen below.

52. Once file transfer is complete, you will receive confirmation as below.

53. You have now uploaded firmware file to the Module flash storage.
54. Issue the following at command to double check file in the list AT+QFLST=”*”
55. Receive +QFLST: “UFS:dfota1.zip”,14026912. If successful downloaded otherwise use AT+QFDEL=”UFS:*” to delete any partial file loaded and repeat steps 43 to 54 above.
56. Issue the following at command AT+QFOTADL=”/data/ufs/dfota1.zip” to initiate firmware update from module flash.
57. Update progress will start.
58. Update progress can be seen on Router logs (see below).

59. FOTA”,”END”,0^M^M indicate that the process is complete and Router firmware update is successful.

Note 3: – If you receive any other number than “0” after “END” contact support@siretta.com with returned error.

60. Reboot Router.
61. Wait for a reboot cycle to complete.
62. Router now is ready with the latest firmware.
63. You can double check the current firmware by using at command AT+QGMR

Note: During remote firmware update make sure the SIM card has enough cellular data to avoid connection loss during uploading firmware package from the local PC to the module of the remote Router.

If you encounter any problem during firmware update or following this guide, please contact support@siretta.com

Additional Reading

The post Updating QUARTZ Router Module Firmware Over-The-Air (Remotely) appeared first on Siretta Limited.

Quick answer

Best for long range: Sub-GHz LPWAN such as 433 MHz, 868 MHz or 915 MHz
Best for low-power cellular: LTE-M or NB-IoT
Best for short-range IoT: 2.4 GHz Wi-Fi, Bluetooth, Zigbee or Thread
Best for high-speed local IoT: 5 GHz or 6 GHz Wi-Fi
Best for industrial private networks: Sub-6 GHz 5G NR bands such as n77, n78 or n79
Common mistake: Selecting the radio module before checking regional bands, antenna size and enclosure constraints

Why frequency band choice matters

Frequency affects how an IoT device performs in the field. Lower-frequency systems generally travel further and penetrate walls, cabinets and equipment better, but they usually carry less data. Higher-frequency systems can support faster connections and denser networks, but range is shorter and antenna placement becomes more critical.

The frequency band also affects the physical design. A Sub-GHz antenna is normally larger than a 2.4 GHz antenna. A wideband cellular antenna must cover multiple LTE or 5G bands. A MIMO 5G router may need several antennas with enough spacing and isolation to work correctly.

For this reason, frequency selection should be treated as a system-level decision, not just a module choice.

Sub-GHz IoT: 433 MHz, 868 MHz and 915 MHz

Sub-GHz bands are widely used for long-range, low-power IoT applications. Typical technologies include LoRaWAN, Sigfox and other LPWAN or ISM-band systems.

These bands are suited to:

• smart metering
• agriculture
• environmental monitoring
• remote telemetry
• industrial sensors

The main advantage is propagation. Sub-GHz signals generally travel further than 2.4 GHz or 5 GHz signals and are less affected by obstacles. This makes them useful for outdoor sensors and devices that only send small amounts of data.

The limitation is data rate. Sub-GHz LPWAN is not intended for video, frequent firmware updates or high-throughput diagnostics. Regional availability also matters: 868 MHz is common in Europe, while 915 MHz is common in other regions, so product variants may be required.

2.4 GHz IoT: Wi-Fi, Bluetooth, Zigbee and Thread

The 2.4 GHz band is one of the most common short-range IoT bands. It supports Wi-Fi, Bluetooth, Bluetooth Low Energy, Zigbee and Thread.

It is often used in:

• smart home devices
• wearables
• consumer IoT
• building automation
• short-range industrial monitoring

The advantage is compatibility. Many phones, routers, gateways and controllers already support 2.4 GHz technologies. Antennas are also compact, which helps in small embedded products.

The main problem is congestion. Wi-Fi, Bluetooth, Zigbee and Thread may all operate in the same band, so coexistence and interference should be checked during testing. Enclosure material, PCB layout, batteries and nearby antennas can also affect practical range.

Cellular IoT: LTE-M, NB-IoT, LTE and 5G

Cellular IoT is used where devices need wide-area connectivity without relying on a local gateway. It uses licensed mobile network spectrum, and the exact bands depend on region, operator, module and SIM.

For low-power cellular sensors, LTE-M and NB-IoT are usually the first options to consider.

LTE-M / Cat-M1 is suited to devices that need low power, moderate data rates and mobility support. It is commonly used for asset tracking, metering, wearables and telemetry.

NB-IoT is suited to very low-data applications where deep indoor coverage and long operating life are more important than speed. Typical uses include static sensors, alarm panels, HVAC monitoring and utility metering.

For these applications, Siretta’s LTE-M and NB-IoT industrial modem range is designed for low-power cellular IoT deployments such as metering, asset tracking, environmental monitoring and remote sensor telemetry.

For higher-throughput applications, a full LTE router is usually more appropriate. If the system needs Ethernet, serial connectivity, VPN support or remote equipment access, a compact 4G router such as the QUARTZ-COMPACT-LTE industrial router is a better fit than a low-power modem.

Mid-band 5G for industrial IoT

Sub-6 GHz 5G NR bands, including n77, n78 and n79, are used where higher capacity, lower latency and dense device support are required. These bands are relevant to private 5G networks, robotics, machine monitoring, smart factories and industrial gateways.

The trade-off is range. Mid-band 5G provides more throughput and capacity than lower-frequency cellular systems, but it usually needs more careful coverage planning. Antenna placement and MIMO layout are also more important.

For industrial 5G routers, gateways and private network equipment, Siretta’s 5G antenna range supports common sub-6 GHz 5G and 4G applications across embedded, terminal, magnetic, through-hole, wall and pole-mounted formats.

5 GHz and 6 GHz Wi-Fi

The 5 GHz and 6 GHz bands are used by high-speed Wi-Fi systems. Wi-Fi 5 and Wi-Fi 6 commonly use 5 GHz, while Wi-Fi 6E and Wi-Fi 7 can use 6 GHz where regulations allow it.

These bands are suited to:

• smart cameras
• enterprise IoT
• video systems
• industrial tablets
• local diagnostics
• high-speed gateways

The advantage is throughput. These bands support faster data transfer and more channel capacity than 2.4 GHz. The disadvantage is reduced range and weaker penetration through walls, metalwork and enclosures.

For local high-speed IoT, 5 GHz and 6 GHz Wi-Fi are useful, but access point position and antenna placement must be validated in the final installation.

Antenna and band selection

Frequency band choice directly affects antenna selection. The antenna must support the required technology, frequency range, mounting method, IP rating and MIMO configuration.

For cellular designs, it is also important to check the exact LTE or 5G NR bands used in the deployment country. A router or antenna may support “4G” or “5G” generally, but still not cover the required regional bands.

The Siretta antenna selector tool can be used to filter antennas by mounting type, cellular technology, Wi-Fi technology, ISM technology, GNSS, IP rating and MIMO configuration.

The Siretta band selector tool can be used to narrow products by LTE bands such as B1, B3, B7 and B20, and 5G NR bands such as n77, n78 and n79.

IoT frequency band comparison

Selection checklist

Before choosing the radio hardware, confirm:

• operating country or region
• required range
• required data rate
• battery or mains power
• indoor or outdoor installation
• static or mobile device
• LTE or 5G NR bands required
• antenna mounting method
• enclosure material
• IP rating
• MIMO requirement
• cable length

Need help selecting the right IoT hardware?

If you can share the deployment region, radio technology, enclosure type, mounting method and expected cable length, Siretta can recommend a suitable modem, router or antenna configuration for evaluation.

Button text: Request recommended sample (https://www.siretta.com/request-for-quote/)

Secondary: Ask an RF engineer (https://www.siretta.com/find-out-more/)

The post IoT frequency bands below 6 GHz: range, power and antenna trade-offs appeared first on Siretta Limited.

A passive GPS antenna consists only of the antenna element. It receives GNSS signals and passes them directly to the receiver with no amplification. In contrast, an active GPS antenna integrates a low-noise amplifier (LNA) directly after the antenna element. This boosts the signal before it reaches the receiver.

This distinction is important because GNSS signals arrive at the Earth at extremely low power levels. Any loss in the system—whether from PCB traces, connectors, or cables—can reduce signal quality and impact positioning performance.

What changes in real installations?

In practice, the difference between active vs passive GPS antennas is not just about gain—it’s about how well the system handles real-world losses.

A passive antenna works well when:

• The antenna is placed directly on the PCB
• The RF path to the receiver is very short
• There is a clear view of the sky

However, performance can degrade quickly if:

• The antenna is inside an enclosure
• The ground plane is limited
• The environment introduces attenuation or interference

An active antenna helps compensate for these losses by amplifying the signal early in the signal chain. This improves the signal-to-noise ratio (SNR) at the receiver input and helps maintain reliable satellite tracking.

Active antennas: benefits and trade-offs

Active GPS antennas typically provide around 15–30 dB of LNA gain, along with filtering to reduce out-of-band interference.

They are commonly used when:

• The antenna is remotely mounted
• The signal path includes connectors or coaxial cable
• The installation environment reduces signal strength

However, more gain is not always better. Excessive amplification can:

• Overload the receiver front-end
• Amplify interference from nearby RF sources (e.g. LTE, 5G)
• Reduce overall system dynamic range

For best performance, antenna gain should be matched to the total system loss.

Passive antennas: where they make sense

Passive GPS antennas are typically used in:

• Compact embedded designs
• PCB-mounted ceramic patch antennas
• Applications with minimal RF path loss

They offer:

• Lower cost
• No power requirement
• Simpler integration

But they rely entirely on good placement, grounding, and system design to perform well.

Power and integration considerations

Active antennas require a DC supply, usually delivered via the RF cable (bias tee).

• Typical operating voltage: 3.3 V to 24 V
• Without power, the LNA becomes a loss element
• Performance may drop below that of a passive antenna

This is a common integration issue in GNSS designs.

Practical summary

The choice between active vs passive GPS antennas is not simply about antenna type—it’s about overall system performance.

• Use a passive antenna when the RF path is short and losses are minimal
• Use an active antenna when system losses or environmental factors reduce signal strength

In most embedded designs, passive antennas are sufficient. But in real-world installations—especially where placement or environment is less controlled—active antennas provide the margin needed for reliable GNSS performance.

Explore Siretta’s range of GNSS antennas or speak to our engineering team for guidance on selecting the right active or passive solution for your design.

The post Active vs passive GPS antennas: what’s the real difference appeared first on Siretta Limited.

In dense urban environments, often referred to as urban canyons, this effect becomes more pronounced. The receiver may only see a limited number of satellites, and some of those may be reflections rather than true line-of-sight signals. Although modern receivers attempt to mitigate this in software, they cannot fully correct poor signal conditions at the antenna.
In practice, this shows up as position drift, slow fix times, or large jumps in reported location, particularly when moving between open areas and built-up streets.

Direct and reflected GNSS signals in urban environments. Buildings block line-of-sight signals and create delayed reflections, leading to positioning errors.

How to improve GPS accuracy in urban environments

1: Antenna placement

The antenna location has the biggest impact on performance.

It should be positioned as high as possible with a clear view of the sky. Mounting low down, inside an enclosure, or close to vertical metal surfaces will increase reflections and reduce direct signal reception. In vehicle applications, a roof-mounted antenna will consistently outperform one placed on a dashboard or inside the cabin.

Keeping distance from nearby metal surfaces is also important. Vertical conductive surfaces act as reflectors and can significantly increase multipath errors if the antenna is mounted too close to them.

2: Antenna type

For static installations, a patch antenna with a suitable ground plane is generally preferred. The ground plane helps maintain a stable radiation pattern and reduces sensitivity to low-angle reflected signals.

For mobile applications, external active antennas are typically used. Antennas such as the Mike 19 provide a practical balance of gain and radiation performance for vehicle or asset tracking, particularly when mounted with a clear view of the sky.

In embedded designs where the antenna must be located inside the product, ground plane size and placement become limiting factors. In these cases, compact active antennas such as the Echo 52 are designed to operate with reduced ground planes while maintaining acceptable polarisation and performance.

3: Antenna gain and noise

GNSS signals are very weak when they reach the earth, so an active antenna with a low-noise amplifier is typically required.

Lower noise figure improves signal quality, but gain must be considered in the context of the full system. Too little gain will result in poor tracking, while excessive gain can raise the noise floor or make the system more susceptible to interference from nearby radios.

4: Cabling

Cable losses can significantly affect performance, particularly at GNSS frequencies.

Where possible, the cable between the antenna and receiver should be kept short. If a longer cable is required, a low-loss coaxial cable should be used and the antenna gain selected to compensate for the additional attenuation.

5: GNSS receiver capability

Using a receiver that supports multiple constellations such as GPS, GLONASS and Galileo can improve performance in urban environments by increasing the number of available satellites and improving positioning geometry.

Multi-frequency operation can also help reduce certain error sources, although it does not eliminate multipath caused by reflections from nearby buildings.

Summary

Poor GPS accuracy near buildings is usually caused by a combination of signal blockage and multipath reflections, rather than an issue with the receiver itself. The most effective improvements come from optimising antenna placement, ensuring a clear view of the sky, and selecting an antenna suited to the installation.

The post Why is my GPS accuracy bad near buildings and how to improve it appeared first on Siretta Limited.

Key Features:

• Low-profile design, 115 mm protrusion from ceiling and 200 mm diameter
• Professional-grade N-Type female connectors
• Available in white or black housing
• Customisation options for connector types and cable length
• 1-2 dBi omnidirectional gain

Find Out More

Key Features:

• Ultra-low-profile design: 11 mm protrusion from ceiling
• SiSo configuration (single port)
• 2–3 dBi omnidirectional gain for consistent indoor coverage
• Plenum cable supporting low passive intermodulation for clean signal performance
• WLAN compatible (IEEE 802.11 a/b/g/n)

Find Out More

Key Features:

• 4×4 MIMO capability with four independent ports
• Wideband coverage: 600–6000 MHz
• Ultra-low profile design (23 mm height)
• Average gain of 5 dBi with peak performance up to 7.47 dBi

Find Out More

Key Features:

• Two cables with N-Type female connectors
• Omnidirectional radiation pattern for uniform coverage
• Low-profile design for discreet ceiling integration
• Balanced performance for medium-density deployments
• Suitable for cost-effective MIMO upgrades

Find Out More

Key Features:

• Optimised for 5G C-band (3300–4700 MHz)
• 4×4 MIMO support via four N-Female connectors
• ±45° slant polarisation for improved signal stability
• Directional radiation pattern for targeted coverage
• Rugged enclosure also suitable for indoor and outdoor use

Find Out More

Key Features:

• Ultra-wideband coverage: 600–8000 MHz
• 4×4 MIMO capability for enhanced throughput
• Suitable for multi-operator and shared network deployments
• Directional pattern for controlled RF distribution
• Designed for both indoor and semi-outdoor applications

Find Out More

Key Features:

• Up to 7.5 dBi gain for extended reach
• Wide beamwidth for effective area coverage
• High port isolation (12–28 dB) for efficient 2×2 MIMO
• Stable directional pattern for controlled coverage
• Supports combined cellular and Wi-Fi environments

Find Out More

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In practice, effective Distributed Antenna Systems design is rarely about choosing one antenna type over another. Ceiling-mounted omnidirectional antennas provide the primary coverage layer across the building, while directional panels are added selectively to address specific challenges. This layered approach ensures consistent performance throughout the space while allowing the network to adapt to more complex environments where additional control is needed.

Real-World Impact Across Industries

Commercial Offices – Lead DAS adoption driven by employee connectivity expectations. Modern offices generate enormous traffic from video conferences, cloud applications, and collaboration tools. DAS ensures robust connectivity in interior conference rooms, basements, and core areas.

Healthcare Facilities – Require DAS for telemedicine, mobile EHR access, patient monitoring, and staff communications. Complex architecture with concrete, steel, and X-ray shielding necessitates carefully engineered solutions for complete patient care area coverage.

Transport Infrastructure – Airports, railway stations, and underground systems combine massive user density with RF-hostile environments. Multi-operator neutral host architectures have become standard, enabling all carriers to share infrastructure.

Stadiums and Arenas – Face the ultimate stress test with tens of thousands of simultaneous users. Sophisticated DAS architectures with extensive antenna arrays and smart monitoring manage dramatic traffic swings between events.

Industrial Facilities – Rapidly adopt DAS for Industry 4.0, robotics, automated vehicles and real-time monitoring. Private 5G networks over DAS provide ultra-reliable low-latency connectivity for automation, with manufacturers achieving significant operational improvements.

 

Smart Building infographic illustrating the role of Siretta RF antennas in delivering end-to-end connectivity across DAS, building systems, security, and smart automation.

The Road Ahead

As demand for indoor connectivity continues to grow, the role of Distributed Antenna Systems is becoming increasingly central to modern network design. Higher frequency 5G spectrum, particularly in mid-band and mmWave, brings significant capacity gains but also introduces greater propagation challenges. This makes reliable in-building coverage not just desirable, but essential.

At the same time, expectations of what indoor networks must support are evolving. Beyond basic connectivity, organisations now rely on wireless infrastructure to enable smart building systems, real-time monitoring, automation, and data-driven decision making. From energy management and security to workplace optimisation and industrial operations, these applications depend on consistent, high-quality coverage throughout the environment.

This shift is changing how indoor connectivity is viewed. It is no longer treated as an extension of the outdoor network, but as a core part of the digital infrastructure that underpins building performance and user experience.

In this context, antenna selection remains a critical part of the overall system design. Ceiling-mounted omnidirectional antennas provide the foundation for consistent indoor coverage, while directional panels are used selectively to address more complex or high-demand areas. Together, they enable flexible, scalable deployments that can adapt to the specific requirements of each environment.

Siretta’s portfolio of Tango ceiling-mounted and Oscar panel antennas supports this approach, offering a range of solutions designed to meet the demands of modern indoor wireless networks. By combining wideband performance, flexible deployment options, and support for both cellular and wireless technologies, these antennas provide the building blocks for reliable, future-ready connectivity.

Ultimately, organisations that invest in robust indoor wireless infrastructure are better positioned to support productivity, efficiency, and innovation. As the volume of connected devices continues to grow and applications become more data-intensive, the importance of getting indoor connectivity right will only increase.

About Siretta

At Siretta, we understand the challenges involved in delivering reliable wireless connectivity and have developed our own antenna selector tool to help reduce time to market. Our portfolio includes cellular modems and terminals, routers, cellular network analysers, and a wide range of RF antennas, including MIMO solutions, as well as products supporting WLAN, LoRa, and Sigfox applications.

We also offer RF cable assemblies and accessories, with solutions typically covering frequencies from 400 MHz to 8 GHz, spanning HF, VHF, ISM, cellular, and GNSS bands.

If you have a project related to Distributed Antenna Systems that you need support with, or would like to discuss the best antenna solution for your deployment, get in touch with our sales team.

The post Distributed Antenna Systems: Powering Next-Gen Indoor Wireless with Advanced Antenna Solutions appeared first on Siretta Limited.

Objective

Quartz routers series use a combination of router and cellular module firmware to function. Router firmware can be updated by following the application note “How to upgrade a Siretta Router Firmware Application Note”

So far, updating router module firmware has been a complex one that involves opening of router casing, removing PCB assembly, detaching the cellular module, plugging the module into a USB adapter then update firmware using a tool called QFLASH. A lengthy procedure requiring Siretta Technical support.

This application note allows users to update the cellular module inside Siretta Quartz series routers using efficient and non-invasive procedure without disassembling the unit.

Solution

DFOTA – Stands for Delta Firmware Update Over-The-Air. DFOTA allows users to update router module firmware using cellular network. Router is set to AT over IP mode where AT command AT+QFOTADL is issued to initiate the update process and point to a location where delta firmware is stored.
Delta firmware file can be either stored in a remote HTTPS/HTTP server or FTP server, this application note covers the procedure were delta firmware file stored in HTTPS server.

Requirements

• Siretta Quartz Series Router (for this applicationQUARTZ-ONYX-GW42-5G (GL) was used)
• Windows 11 Laptop with Tera Term Version 4.96 or above (Tera Term can be downloaded from the following link – Tera Term Link ).
• URL where Delta Firmware file is stored.
• AT Command over Internet Protocol Router Guide

Demonstration of Solution

1. Follow router quick start guide for initial router settings.
2. Wait for the router to connect to the cellular network.
3. Confirm that router has received IP addresses (See below).

4. Navigate to a Basic Network in router GUI.
5. Select Cellular tab.
6. Uncheck Modem Enable checkbox

7. After unchecking Enable Modem check box, page will look like below.

8. Click Save button.
9. Wait for about 3 seconds.
10. You will receive page below.

11. Click Reboot Now.
12. You will receive reboot prompt below.

11. Click Reboot Now.
12. You will receive reboot prompt below.

15. Open Overview page (see below).

16. Navigate to a Basic Network in router GUI.
17. Select Cellular tab.
18. Confirm Modem Enable checkbox is unchecked (See below).

19. Open AT Command over Internet Protocol Router Guide
20. Follow steps 1 to33 of the AT Command over Internet Protocol Router Guide.

Note: Router IP address in AT Command over Internet Protocol Router Guide is 172.168.1.1 which is different from the router IP address used in this guide (192.168.1.1). Replace 172.168.1.1 with 192.168.1.1 and continue with the rest of the application note.

21. You will be presented with Tera Term window.

22. You have now established connection with the cellular module inside the router.
23. Issue the following set of AT commands to query modem and initiate DFOTA process.
24. Issue AT+CREG? – to Check the network registration.

25. Receive following when registered to a local network: +CREG: 0,1.
26. Receive following when registered to a roaming network: +CREG: 0,5.
27. Issue AT+CGPADDR=1 to Check if the context is activated.

28. Receive IP address when context is activated: +CGPADDR: 1,”10.188.232.13″

Note: If no IP address is returned issue AT+CGACT=1,1 to activate context or contact support@siretta.com. Your returned IP address may be different from the above depending on your SIM card provider.

29. Issue AT+QGMR to receive full current firmware version.

30. Full current firmware version is RM500QAEAAR13A03M4G_01.201.01.201.

31. Obtain link from Siretta representative for Delta Firmware package location.

32. For this guide the following link was used http://portal.siretta.com/uploads/DELTA/sign_to_RM500QAEAAR13A03M4G_01.203.01.203_118669193e.zip.

33.Issue the following at command to initiate firmware update over Air.

AT+QFOTADL=”http://portal.siretta.com/uploads/DELTA/sign_to_RM500QAEAAR13A03M4G_01.203.01.203_118669193e.zip”

34.You will receive OK, when successful.

35. Followed by the indication of the status of upgrade +QIND.

Note: 0 indicates firmware was successfully loaded to the module flash storage and upgrade was successful. If you receive any number other than 0 contact support@siretta.com.

You may only receive +QIND: “FOTA”,”HTTPSSTART”, if you see this wait for about 3-5 minutes, as firmware update is taking place in the background then power cycle the router.

36.After receiving no error an automatic firmware update will commence, and you will be unable to send any AT command to the module.

37. After receiving QIND: “FOTA”,”END”,0 the firmware update is successful.

38. Power cycle router.

39. Re-open terminal and query module current firmware by using the following at command AT+QGMR

40. Full current firmware version is RM500QAEAAR13A03M4G_01.203.01.203

41. You have successfully updated module firmware from RM500QAEAAR13A03M4G_01.201.01.201 to RM500QAEAAR13A03M4G_01.203.01.203 using DFOTA.

Note: During firmware update make sure the SIM card has enough cellular data to avoid connection loss during uploading firmware package from the server to the module.

42. Navigate to a Basic Network in a router GUI.

43. Select Cellular tab.

44. Check Modem Enable checkbox.

45. Reboot the router.

46. Wait for the reboot cycle to complete.

47. Router is ready for use with the latest firmware.

If you encountered any problem during firmware update or following this guide, please contact support@siretta.com

Additional Reading

The post Updating QUARTZ Router Module Firmware Over-The-Air appeared first on Siretta Limited.

What is ZeroTier?

ZeroTier is a software that creates a virtual private network (VPN) solution.

ZeroTier VPN supports client to client communication, where several clients are connected to the central server and securely communicate with each other using end to end encryption.

ZeroTier client is compatible with Window 11, Android, MacOS, Linux, Raspberry Pi and Docker Operating Systems.

Objective 

This application note shows how to configure and use a QUARTZ router as a ZeroTier client. The Zero Tier server to which it is connecting is running on another platform. VPN traffic  is not passing through a server. The purpose of server is to match clients.  

The most likely reason a VPN is used in the context of an industrial router is to allow secure remote access to a corporate network and allow encrypted end to end communications between clients. 

Therefore, Siretta recommends using a cabled connection between the QUARTZ 5G router and the devices connected to it (the routers clients) when using a VPN to minimise the possibility that this connection be intercepted or monitored. 

ZeroTier makes it quite easy to set up and use a VPN tunnel.  

Solution 

When Zerotier client is installed and configured to any device with a compatible operating system, the device can directly and securely communicate with the Siretta router using its IP address, when they are connected to the same network using Zerotier VPN. 

In this application note Zerotier client is installed and configured in a Windows 11 laptop and communicates with built-in Zerotier client in the Siretta router. 

Requirements  

• Window 11 Laptop – (Client) 

• QUARTZ-ONYX-W42-5G (GL) – (Client) 

Demonstration of Solution 

1. Follow router quick start guide for initial router settings.
2. Wait for the router to connect to the cellular network.
3. Confirm that router has received IP addresses (See below).

4. Follow ZeroTier Quick Start Guide to create a new account if you don’t have one.
5. Once an account is created you will be presented with the following page.

6. Take a note of a Network ID (5b6e887e28f64f9 for this setting).
Note: You may have a different network ID depending on your settings.

7. In basic setting you can name your network to a name of your choice. For this setting “Testing Siretta Router” was used.
8. In the description box, you can add any description to reflect the purposes of your network.
9. For this setting description of “Siretta Router is a ZeroTier client” was used.
10. After adding the information above, the page will look like:

11. Check “Private” radio button in Access Control.
Note: This setting will allow client to be authorised first before joining the network (See below).

12. Other setting is Public where client can join to the network just by using network ID without authorisation.
Note: For security reasons Siretta does not recommend setting network as Public.

13. Click advanced settings IP4.
14. Check Auto -Assign from range box.
15. Select Easy option (see below).
16. Select IP address range of your choice.
Note: For this guide setting of “192.168.191.*” was selected.

17. Leave the settings for IPv6 Auto-Assign unchanged.
Note: Siretta Router does not have a support for IPv6.

18. Leave the settings for DNS unchanged.

19. Setting for a network is now complete.
20. Clients can be added to the network by using Network ID: 45b6e887e28f64f9.
Note: If you have encountered any problem during network settings, please see “Settings Help” section or contact Siretta support support@siretta.com

Adding Clients to a Network

Adding Siretta Router to a ZeroTier Network

21. In Siretta router GUI navigate to VPN tab (See below).

22. Click Zerotier tab.

Note: If the Zerotier tab is not present in your router then you may have an older firmware version contact support@siretta.com for firmware update.

23. You will be presented with the screenshot below.

Note: Current settings do not use the following parameters Zerotier Moon Network ID, Allowed NAT, Zerotier Moon, Zerotier Moon IP, Zerotier Moon ID, Custom Planet and Uploading Planet File, these parameters are reserved for users who create and host their own Zerotier server.

24. Check Zerotier Client box.
25. Add Zerotier World Network ID.

26. Click Save.
27. Wait for about 10 seconds for service to restart.
28. You have successfully added router to Zerotier server.
29. Confirm that router is added to Zerotier user interface (See below).

30. Router is added to the network but no authorised to use network service.
31. Click Edit tab, you will see screenshot below.

32. Check Authorised box to Authorize device to join and use network service.
33. Add name of your choice, for this setting “QUARTZ-ONYX-W42-5G (GL)” was used.
34. Add description preferred to your settings, for this example “Siretta Router “was used.
35. Click Save button.
36. You have successfully authorised the Siretta Router to join the network (See Below).

37. Refresh ZeroTier user interface to see new device is added to the network and has been given a local IP address.

38. QUARTZ-ONYX-W42-5G (GL) was assigned an IP address of 192.168.191.249, this IP address can be used to communicate with other clients added to the same network.
39. Navigate to Basic Network settings in a router GUI.
40. Select Routing tab, you will see ZeroTier route as seen below.

41. QUARTZ-ONYX-W42-5G (GL) is now added to the Zerotier Server and can be accessed using IP address of 192.168.191.249 by another client connected to a same network.

Adding Window 11 Laptop to a ZeroTier Network42.

Download Zero Tier to your PC depending on your operating system, for this setting Microsoft Windows was downloaded

43. Run ZeroTier One.msi installer to your PC
44. Click Install.

45.Click Finish.
46. You have successfully installed ZeroTier Client to the Window 11 laptop.

47. Right Click Zerotier icon in system tray

48. You will be presented with the following menu.

49 .Click Join network, you will be presented with dialog box below to enter 16-digits Network ID.

50. Enter Network ID, which is 45b6e887e28f64f9 for this setting.

51.Click Join
52. You have now added Window 11 laptop as a client to Zerotier Server.
53. Open View Network connection in the laptop, you will see Zerotier network is added.

54. Confirm that Laptop is added to a server in a Zerotier user interface (See below).

55. Laptop is added but not authorised to use network service.
56. Authorise Laptop by clicking edit check box.

57. Check Authorised check box above.
58. Add laptop name of your choice, for this setting “Window 11 Laptop” was used.
59. Add description of your choice, for this setting Laptop Client was used (See below).

60. Click Save.
61. Laptop now is authorised and added to a network.

62. Check on Zerotier user interface, you will see Window 11 Laptop added to the member list as seen below.

63. Window 11 Laptop is successfully added to the Zerotier server with the local IP address of 192.168.191.174.
Testing communication between ZeroTier clients.
64. Use Window 11 Laptop to ping QUARTZ-ONYX-W42-5G (GL) by using an IP address of 192.168.191.249.

65. Ping was Successful, Window 11 Laptop can communicate with QUARTZ-ONYX-W42-5G (GL).
66. You can use Window 11 Laptop to manage QUARTZ-ONYX-W42-5G (GL).
67. Use QUARTZ-ONYX-W42-5G (GL) to ping Window 11 Laptop by using an IP address of 192.168.191.174.(See below).

68. Ping was Successful, QUARTZ-ONYX-W42-5G (GL) can communicate with Window 11 Laptop.

Additional Reading

The post Using ZeroTier VPN as a client with QUARTZ routers appeared first on Siretta Limited.

In most wireless products like IoT sensors, routers, gateways, trackers, the RF module and PCB is protected by the device enclosure, but the externally mounted antenna has to live on the enclosure. That creates a classic integration problem:

How do you pass a 50 Ω RF signal through the casing without breaking the PCB, detuning the antenna, or creating intermittent failures?

In the real world, these failures aren’t usually RF theory problems. They’re mechanical: torsion from an SMA connector, repeated antenna swaps, vibration, cable tugging, or over-tightening that transfers load directly into a small PCB-mounted connector, eventually cracking solder joints or lifting pads.

The fix is simple and proven: design the RF cable assembly so the enclosure takes the load, not the PCB.

The rule that prevents most RF interconnect failures

The PCB should carry electrical signal. The enclosure should carry mechanical load.

That means your antenna connection should be “serviceable” and mechanically anchored at the enclosure, with a short coax jumper in between.

The recommended RF interconnect stack-up

RF module → PCB RF connector → coaxial pigtail cable assembly → bulkhead connector → antenna

Why this works:

• The bulkhead connector (SMA bulkhead, N-type bulkhead, TNC bulkhead, etc.) is clamped to the enclosure.
• Antenna torque and user handling stop at the enclosure wall.
• The coaxial cable assembly isolates the PCB from strain, vibration, and repeated mating cycles.

Choosing the right RF connectors (SMA, N-Type, BNC, TNC, SMP)

Connector choice is where most teams accidentally design-in future failures. Use connector families based on environment, mating cycles, and size.

SMA connectors (most common for compact products)

Use SMA when you need:
• a compact footprint
• wide antenna availability
• good performance at high frequencies

Watch-outs:
• SMA is easy to over-torque.
• If SMA is mounted directly to a PCB, it commonly cracks solder joints or lifts pads over time.

Best practice:
• Use an SMA bulkhead connector on the enclosure and a short internal coax jumper.

N type connectors (rugged, higher power, outdoor use)
Use N-type connectors when you need durability, sealing options, and lower loss at longer cable runs.

Best practice:
• N-type is almost always an enclosure/bulkhead interface, not a PCB interface.

BNC connectors (quick connect/disconnect, test setups)
BNC connectors are common in test or instrumentation environments. For products with frequent connect/disconnect, BNC may outperform threaded interfaces in service workflows, but it’s physically larger and not typical for small IoT enclosures.

TNC connectors (threaded BNC-style for vibration)

If vibration is expected and you like the BNC form factor, TNC connectors are often a better choice due to the threaded coupling.

MMCX / MCX (Compact Board-Level RF Connectors)

MMCX and MCX connectors are compact snap-on RF interfaces commonly used at the PCB edge to connect to an internal coaxial cable assembly. While they work well as a board-level transition point, they are not designed to absorb mechanical stress from external antennas. For enclosure-mounted antennas, a short pigtail should transition from MMCX or MCX to a bulkhead-mounted SMA or N-type connector to protect the PCB.

Selecting the coax pigtail: cable type, size, and durability

The “pigtail” isn’t just a cable; it’s a mechanical decoupler. Selection should prioritize bend life, strain relief, and repeatability.

Common choices:

• 1.13 mm micro-coax: ultra-compact routing, but easier to damage and kink
• RG-178: flexible, durable for many embedded devices
• RG-316: tougher jacket, better for harsher handling and higher-temp environments

Best practices:
• Keep the pigtail as short as routing allows (to reduce loss and clutter)
• Avoid tight radii and sharp bends (protect impedance consistency and bend life)
• Add strain relief near the PCB connector and near the bulkhead
• Route away from pinch points, screws, and enclosure seams
• For high-vibration or continuous shock environments, consider using locking micro-coax connectors such as I-PEX MHF 1 LK or MHF 4 LK, which provide improved retention compared to standard snap-on types

Image caption: At the mating connector, the cable should run flat along the PCB so that there is no leverage stress applied to the connector which could damage the connector and break the connection. If necessary, it is suggested that some hot melt glue be applied to the cable to attach it to the PCB to provide stress relief.

When mating micro-coax connectors such as U.FL, GSC, I-PEX MHF 1 or I-PEX MHF 4, correct installation technique is critical to avoid damage to the PCB receptacle. Always align vertically and press straight down onto the receptacle rather than applying side force.

Bulkhead connectors: the enclosure is your mechanical anchor

Bulkhead hardware is what makes the whole architecture reliable.

Best practices:

• Mount the bulkhead connector to the enclosure, not the PCB
• Ensure proper grounding on metal enclosures (good RF return path)
• Use lock washers and sealing rings as needed (especially for vibration or outdoor use)
• If the enclosure is plastic, consider grounding strategy and antenna placement carefully to maintain performance

The failure modes this design prevents (and how)

If your product is experiencing range dropouts, intermittent performance, or returns after installation, these are common culprits:

• PCB connector peel/lift from antenna torque
• Micro-coax damage from bending or assembly pinch points
• Intermittent contact from poorly supported coax transitions
• Ground/return discontinuity at the enclosure interface

A well-designed RF coaxial cable assembly stack-up eliminates most of these by keeping the mechanical load path in the enclosure.

When a custom RF cable assembly is worth it

Off-the-shelf pigtails are fine for prototypes, but production products often benefit from custom RF cable assemblies when you need:

• controlled length + routing
• specific connector combinations (U.FL or I-PEX to SMA bulkhead, MMCX to N-type, etc.)
• improved strain relief or ruggedization
• consistent performance across builds (repeatable loss/VSWR)

If you’re building at scale, “custom” often means fewer assembly defects and fewer field returns.

Takeaway

Antenna performance and RF interconnect design must work together. A high-quality antenna cannot compensate for a poorly designed RF cable assembly or mechanically unstable connector interface.

If you want fewer failures:

• anchor your connector at the enclosure
• use a short RF cable assembly inside
• protect the PCB from torque, bending, and vibration

For high-quality RF interconnect solutions, Siretta Ltd offers a comprehensive range of RF pigtail cable assemblies designed for industrial and IoT applications. Covering common connector configurations and frequencies from 150 MHz to 8 GHz, Siretta supports both standard and customised cable assemblies, allowing specification of connector types, cable lengths and shielding options to suit specific integration requirements.

Browse the full RF pigtail cable range here

The post RF Cable Assembly Design Guide: Getting a PCB RF Module to an External Antenna (Without Field Failures) appeared first on Siretta Limited.

End-of-life (EOL) announcements are becoming more common across the cellular IoT market. As manufacturers rationalise portfolios, merge product lines or exit legacy technologies, many widely deployed modems are being discontinued — often while customer installations are still active in the field.

For system integrators, OEMs and asset owners, this creates a familiar problem: what happens when the modem your product relies on is no longer available?

Why IoT modems are being EOL’d

There are several industry-wide reasons behind the increase in modem EOL notices:

• Vendor consolidation following acquisitions and mergers
• Technology transitions, such as the move away from 2G/3G to LTE-based solutions
• Component availability and chipset lifecycle changes
• Rationalisation of overlapping product ranges

Manufacturers are understandably focused on future platforms, but this often leaves customers managing long-life deployments with suddenly unsupported hardware.

The real impact of EOL on deployed systems

An EOL modem doesn’t just affect procurement — it can trigger wider technical and commercial risk:

• Forced redesigns of certified products
• Re-testing and re-approval for regulated industries
• Firmware changes and new AT command sets
• Stock shortages for spares and replacements
• Unplanned costs and extended downtime

For applications with 5–10+ year lifecycles, these disruptions are far from trivial.

What to look for in an EOL replacement modem

When sourcing an alternative to an EOL’d modem, engineers typically prioritise:

• Form-factor compatibility (physical size, mounting, connectors)
• Interface continuity (RS232, RS485, USB, Ethernet)
• Network longevity (LTE Cat-1, LTE-M, NB-IoT rather than legacy 2G/3G)
• Minimal firmware changes
• Long-term availability commitments

The goal is simple: keep the existing system working with minimal redesign effort.

ZETA modems as a continuity option

For many applications, ZETA industrial cellular modems are used as a drop-in or low-impact replacement when legacy or discontinued devices are no longer available.

Key characteristics include:

• Industrial-grade design for long-term deployment
• Support for LTE Cat-1, Cat-4, LTE-M and NB-IoT, aligned with network longevity
• Common industrial interfaces (RS232)
• Ultra-Low power consumption ideal for low power applications
• Simple integration without proprietary software lock-in
• Reliable and dependable technical support

Rather than pushing customers into frequent platform changes, the focus is on continuity and longevity

Avoiding future EOL disruption

While EOLs can’t be eliminated entirely, they can be mitigated:

• Choose modem platforms with clear lifecycle visibility
• Avoid over-customised or proprietary device dependencies
• Standardise on widely supported cellular technologies
• Maintain second-source or alternative options early in the design phase

Planning for lifecycle stability at the outset significantly reduces long-term risk.

Final Thoughts

EOL announcements are an unavoidable part of the IoT industry, but they don’t have to mean forced redesigns or costly delays. By selecting industrial modems designed with longevity in mind, businesses can maintain continuity even as the wider market evolves.

For organisations facing discontinued modem platforms, ZETA remains a practical, available option — supporting modern cellular networks while keeping existing systems operational.

The post When IoT Modems Go End of Life: How to Avoid Forced Redesigns appeared first on Siretta Limited.

Objectives

The purpose of this application note is to give a brief background on 5G (NR) wireless communication an explain the reason a SNYPER-5G Graphyte may need a SIM card to give more rounded survey results.

5G NR (New Radio) communication

5G is the fifth-generation wireless cellular technology, developed by 3GPP with faster speeds, higher capacity, lower latency, and increased reliability compared to 4G (LTE) architecture. It is designed to support a wider range of devices and applications, from smartphones to smart cities to driverless cars, generally the Internet of Things (IoT). There are two architectures that Network Operators employ for 5G network cellular communications.

NSA (Non-Stand Alone) and SA (Stand Alone)

• The NSA architecture was devised so that the operators could use the existing 4G (LTE) structure to take advantage of 5G. When a 5G call is made using NSA, the signals use 4G (LTE) to connect to the cells. The LTE cells then convert this to the 5G capable equipment to make use of the low latency and high bandwidth that 5G offers. Basically, 5G NSA is backwards compatible with 4G (LTE)

• The SA architecture (a 5G only infrastructure) was deployed around 2023 for operators to use for 5G capable equipment. This makes full use of 5G capabilities.

Why is it sometimes necessary to use a SIM card when using SNYPER 5G

SNYPER 5G, like all SNYPER Cellular Signal Strength analysers, surveys all the nearby cells without a SIM card and shows which networks are stronger in a specific area to allow the user to choose the best SIM card/Network for their cellular real estate.

When running a survey, the SNYPER 5G will show all cells using 5G (SA) and LTE technologies. It is however, incapable of showing 5G NSA communication, as it cannot “see” which 4G (LTE) cell was used to pass on the 5G signal (since network operators use the LTE infrastructure for the initial connection), then communicate with 5G capable equipment.

To overcome this issue, the SNYPER 5G should be equipped with a 5G SIM card. The SIM card then decodes which 4G LTE cell was used for 5G communication.

It should be noted that when using a SIM card in SNYPER 5G the results will only show the cells from the network that the SIM card belongs to. To overcome this, it is recommended that a Roaming SIM card is used, although the results will be limited to the networks that the Roaming SIM card can connect to.

The post Why Use a SIM Card With The SNYPER-5G appeared first on Siretta Limited.