Your DMR Repeater will not work once the Internet goes down? (Part 1)

A while ago I overheard a conversation between two radio amateurs discussing DMR and that DMR Repeaters will not function once the Internet goes down.  They were of the opinion that these new digital repeaters are useless if the Internet is down during a disaster or emergency.  This discussion set me thinking - always dangerous but I decided there must be a way/ways to run a DMR Repeater without the Internet.  Before I explain one of the methods I found to work flawlessly when there is no Internet, lets first look into the reasons why one would run a DMR Repeater without the Internet.

The question was how to run a standalone MMDVM DMR Repeater with no access to the Internet. First question is why? 

DMR systems must be connected to the Internet, otherwise it just does not work correctly and does not make any sense. Well, it is not entirely true and I will prove the point that DMR Repeaters can still operate locally when there is no Internet.

There are two reasons for running a standalone DMR repeater in a very remote locations with no chance of having Internet access.  You can use Talk Group 9  to communicate within direct range of the repeater.  More on how to setup your DMR Radio in this regard further on in the article.

The second reason of running a standalone DMR repeater is for use during natural disasters and any other random legitimate reasons.   Make sense in this day and age to be able to use a digital repeater for emergency communications.

The first thing I found is if the repeater is connected to the Internet (through a router) using an Ethernet cable and if the cable gets unplugged, the repeater is still working locally (TG9) without any problem.

However – once the repeater restarts, and there is not access to the Internet network (even local RF transmissions) the repeater does not work anymore.

I hear you say but I told you so and that the two radio amateurs having the discussion were not wrong.  Your DMR Repeater is useless without the Internet!!

Well there are several ways to solve the issue of no Internet to a standalone MMDVM DMR Repeater.  In part 1 we will be looking at setting up a DMR repeater on a AREDN Mesh Network without the Internet.  Let's get cracking!

Image:  AREDN ZS1I Main Node

Setting up a DMR repeater on an AREDN mesh network enables off-grid digital voice communications by replacing internet backhaul with RF links. Use AREDN firmware on compatible nodes to establish a "tunnel" or direct RF link, mapping your node to the network. An MMDVM-based repeater connects directly via Ethernet to the AREDN node. 

Key Components & Setup Steps

• AREDN Node: Ubiquiti or Mikrotik radio flashed with AREDN firmware.
• DMR Repeater: An MMDVM-compatible repeater (e.g., using a Raspberry Pi and MMDVM modem).
• Networking: The MMDVM node connects to the LAN port of the AREDN node.
• DHCP/Routing: The AREDN node acts as the network gateway, providing an IP address to the MMDVM Repeater.

Integration Process

1. Mesh Link Establishment: Ensure your AREDN node has a strong, reliable link to the mesh network using directional antennas.
2. DMR Setup: Configure the MMDVM host (Pi-Star or WPSD) to use a static IP within the AREDN network range or DHCP.
3. Bridge Connection: Use a DMR bridge (like cBridge) to connect to a Master Server over the mesh instead of the public internet.
4. Network Testing: Check for 100% connectivity. AREDN nodes should show the MMDVM IP in their DHCP table.

I will not be going into great detail here as AREDN Main Mesh Nodes differ from one to the other depending on which equipment you are using.  My equipment is fairly old as I started playing around with mesh networking in early 2002 when it was called HSMM (High Speed Multi Media) which used Linksys WRT54GL routers.  In 2015 I moved to AREDN which at the time was using Ubiquity equipment. In November 2016, I started a community organization called Mossel Bay Initiative (MBI)  a pilot program for the AREDN Mossel Bay Mesh Network. More on this in a future posting. Through the years several other products were added to use with AREDN.  Comprehensive list of equipment  available HERE.

View the video below for my setup and an overview of how I used AREDN with my DMR Repeater while there is no Internet connection.

In short crypto I setup the equipment as follows:

1.  I use a Netgear GS105E Switch that connect all the equipment together.  The switch has 5 Ethernet ports and I allocated them as below:

Port 1 = ZS1I Mesh Server (Web Pages) running on a Raspberry Pi.

Port 2 = ZS1I-2 AREDN Node running a  Ubiquity Nano Beam M5 16

Port 3 = Windows 7 Desktop PC to view dashboards etc.

Port 4 =  ZS1I DMR Repeater using a Raspberry Pi 

Port 5 =  Internet connection when available from a Router.  This port stayed open as we do not want any Internet connection.

2.  Startup AREDN Main Node, Computer, DMR Repeater if not already running.  IP addresses will be allocated by the ZS1I-2 AREDN Node. In my case 5 IP addresses were allocated. I use Advanced Port Scanner to obtain the IP addresses. For now 3 IP's are important to gain access and to view dashboards.  This would be the ZS1I-2 AREDN Main Server Node; the DMR Repeater WSPD Dashboard and the Window 7 Desktop PC Browser to access the ZS1I-2 Node and the WPSD Dashboard for ZS1I (the latter not connected to the Internet but to AREDN).

 

 

 

3.  Lets look at how to open and view AREDN node information and the WPSD dashboard.

Access the AREDN node via the Window 7 Internet Browser.  Enter the allocated IP address for the node and click enter. The ZS1I-2 Mesh Node status page will open.  Login under Setup and once logged in you can go through all the different screens and pages.

 

 (Click on image for larger view.)

 

As far as the WPSD Dashboard, open the dashboard via the Window 7 Intenet Browser.  Enter the allocated IP address for WPSD and click enter.  The WPSD Dashboard for ZS1I will  open.  The dashboard will reflect that DMR and DMR Net are active (Green) while APRS Net and DMR Master BM 6551 South Africa is not active (Red).  In other words off-line.  So there is no Internet connection but the DMR Repeater is still working locally in the Mossel Bay area.

 

I programmed all my DMR radios to use TG65522 (World Wide Repeater Talk Group) and TG9 (Local Talk Group).  

 

 

(Click on images for larger view.)

Setting up Talk Group 9 (TG9) on a TYT MD380 for repeater use requires creating a digital contact for TG9, establishing a new channel with specific repeater parameters, and adding that channel to a zone. TG9 is frequently used as the "Local" talk group on DMR repeaters for local traffic or to link to other talk groups.

1. Create a Digital Contact for TG9 

• Open the TYT CPS (Code plug Programming Software) and navigate to Digital Contacts.

• Click "Add" and create a new contact:

  • Contact Name: TG9 (or Local 9).

  • Call Type: Group Call.

  • Call ID: 9. 

2. Create a Channel for the Repeater

• Navigate to Channel Information and click "Add" to create a new channel.

• Configure the following settings:

  • Channel Name: Choose a name (e.g., "Local 9" or "Rep TG9").

  • RX Frequency: Set to the repeater's output frequency.

  • TX Frequency: Set to the repeater's input frequency.

  • Channel Type: Digital.

  • Color Code: Match the repeater (usually 1).

  • Timeslot: Match the repeater (often TS2 for local/TG9).

  • Contact: Select "TG9" (the contact created in step 1).

  • RX Group List: Select a group list that includes TG9.

3. Add Channel to a Zone 

• Go to Zone Information and select the desired zone (e.g., Zone 1).

• Move the newly created channel from the "Available Channels" list to the "Members" list. 

4. Finalize Programming

• Go to General Settings and ensure your personal DMR ID is entered.

• Use "Write Data to Radio" to upload the new configuration to the MD380.

Important Notes for TG9 Usage:

• Local Communication: TG9 is designed for local QSOs and is not typically transmitted over the internet to other repeaters.

• Linking: In some systems, such as FreeDMR, you can link to other talk groups by using TG9 and the "Dial-a-TG" function (using manual dial).

• Timeslot: Always confirm with the local repeater manager whether they use TS1 or TS2 for local traffic. 

• Parrot Channel: It is recommended to create a “Parrot” (Echo) channel to test that your radio’s settings work correctly.

• Repeater Access: Ensure you have the correct frequencies (Offset) for the repeater and that your colour code is correct.

• Promiscuous Mode: If using custom firmware you can turn on Promiscuous Mode to hear all talk groups regardless of the RX Group List.

 

Above: Video of the equipment setup and demonstrating the use of the DMR Repeater without the Internet.

 

The information provided in this article resolved the problem of no Internet for my DMR Repeater while it usually work with Internet access.  As already stated this is one solution.  In future topics I will be looking at other methods on how to run a DMR Repeater with no access to the Internet. Some of these solutions are quite simple but seeing that I have an AREDN Mesh Network running, I wanted to us the method described in this article.

Keeping the ZS1I DMR Repeater in Mossel Bay cool!

Image:  Fans and Fan Speed Contoller fitted to the DMR Repeater.

In the previous article I described the two PWM Fan Controllers that I purchased to install in the MMDVM Repeater to keep it cool during those hot summer days.  I setup the controllers and tested them at different temperatures on the workbench.  So far they work as expected.  I fitted the two controllers in a 3D printed project box and installed it at the back of the DMR Repeater.

I opted to mount the fans on the outside of the repeater cabinet as the spacing inside the repeater cabinet makes it rather difficult to work on the fans and installing the controllers.  By mounting the fans and fan controller box on the outside of the repeater cabinet, it is now easy to access the controllers and service/replace the fans when necessary.

The modification turned out quite well and the fans and controllers are working as it should. Herewith a few images of the repeater after installing the new fans and controllers.

Images:  Click on images for larger view.

Keep your Repeaters, Simplex Radio's and Raspberry Pi's cool

Image:  PWM Fan Contoller  (Click on image for larger view.)

Well this is a bit late to cool things down as we say good bye to summer and hello to winter.  I wrote several articles in the past providing information on building you own Thermo-Fan Controllers for use to keep radios, raspberry pi's and other electronic equipment cool during operation.  All of these controllers are still in operation on a daily basis and up to now I have not had any problem with any of them.

I recently noticed that my DMR Repeater fans are very noisy and I suspected that they are close to failure as they have been in operation for several years now.  Low and behold two days ago one of the TX fans decided that it had enough and failed as expected.

I considered to build another trusted IC741 op-amp Thermo-Fan Controller for use with the DMR Repeater.  As the years are creeping up on me and the eye-sight not being so good anymore I decided I would rather buy a ready to use simple/cheap PWM Fan Controller.   I ordered two different models.  In this article I will only provide information on the one model depicted in the images below.

The controller is designed as a model that combines manual control and automatic temperature control.

Here is more information on the specific model:

This single-channel PWM fan controller is designed for 12V DC fans, supporting both 2-wire and 3-wire fan types for precise speed regulation.

 

It enables smooth, efficient, and stable fan speed control, making it ideal for cooling systems, industrial equipment, and DIY thermal management projects.

 

Key advantages:

• Single-channel PWM speed control

• Supports 12V DC fans (2-wire / 3-wire)

• Smooth speed adjustment with low noise

• Compact module for easy installation

• Ideal for cooling systems and thermal control

 

Other detail:

Input Reverse Connection Protection: Yes
No output overload protection.
Power Interface: XH-3P Terminal Block (2.54mm Pin Spacing)
Fan current: 0.8A (not overloaded)
Fan Interface: KF2510-3P Terminal Block (Pin Spacing 2.54mm)
Temperature sensor parameters: NTC 50K B = 3950 Length = 50 cm.
Temperature Sensor Interface: XH-2P Terminal Block (Pin Spacing 2.54mm)
Temperature resistance of probe: ring probe 110℃
PWM Output Range: 5% to 100%
Operating temperature: -20°C ~ 60°C.
Dimensions: 43 x 18 x 9 mm. 

I am not going to go into detail on programming and setting up the controller as YouTube and Google is your friends here.

Finally:  I setup the controllers and tested them at different temperatures on the workbench.  So far they work as expected.  I will be fitting the two controllers in a 3D printed project box and install it at the back of the DMR Repeater to provide the necessary cooling when needed.

Images:  (Click on images for larger view.)

Videos:

 

Today, 18 April is World Amateur Radio Day!!

 

Invitation: "Saturday Afternoon Amateur Radio On-The-Air Activities"

I invite radio amateurs to join the "Saturday Afternoon Amateur Radio On-The-Air  Activities".  Please take note that this is not a structured / stereo type net or event. 

Activity - "Saturday Afternoon Amateur Radio On-The-Air  Activities from the Southern Cape Area"
Day of the Week - Saturday Afternoons
Time - 15h00 SAST
Place -  ZS Link Network

This afternoon's topic:

Which of the antennas is the better antenna with a higher gain? Slim - Jim or J-Pole Antenna. 

Join this amateur radio activity this afternoon.

Ek nooi radioamateurs uit om aan te sluit by die "Saterdag Middag Amateur Radio Aktiwiteite Op-Die- Lug". Neem asseblief kennis dat hierdie nie 'n gestruktureerde / stereotipe net of geleentheid is nie.

Aktiwiteit - "Saterdag Middag Amateur Radio Aktiwiteite op-die-lug vanuit die Suid-Kaap gebied"
Dag van die week - Saterdagmiddae
Tyd - 15:00 SAST
Plek - ZS Link Network

Vanmiddag se onderwerp:

Watter een van die antennas is die beter antenna met 'n hoer wins?  Slim - Jim of J-Pole Antenna.  

Sluit gerus aan by die amateur radio aktiwiteit vanmiddag.

 

List of Stations connected to the ZS Link Network for the above activity:

(Click on image for larger view.)
 

Why do radio amateurs not leave large enough gaps ("overs") between transmissions?

Does the title of the above article sound familiar? 

On numerous occasions the ZS Link Network experience the "to quick on the trigger (PTT)" habit. Yes it is a bad habit and the author is also guilty at times.  No pointing of fingers here let's find out why this happens.

I wrote the following this morning on the WhatsApp Group:

"Gaps, gaps etc. Stations cannot connect to the ZS Link Network Group's networks. Stations are left out in the cold. We must please leave gaps and not be so quick to press the PTT between overs. There are some of our regulars who want to connect to the DMR links and other systems, but cannot get in. Let's please leave long enough (5-8 seconds) gaps between rounds. We don't want to lose stations because they can't connect/disconnect or log in. No, I have nothing to do with the administration of the network anymore, but just felt like bringing it to everyone's attention again in the interest of the group. - ZS1I"

In amateur radio, failing to leave a gap between "overs" (transmissions) is known as "quick-keying" or "tailgating." Experienced operators strongly advise against this because it disrupts the flow of communication and violates standard Ham Radio Etiquette.

Now why do radio amateurs not leave large enough gaps ("overs") between transmissions?

Radio amateurs often fail to leave sufficient gaps ("overs") between transmissions due to a combination of ingrained habits from crowded operating environments, the desire to prevent others from "stealing" the frequency, and the rapid, conversational nature of "rag-chewing" (casual chatting). 

Common reasons for short breaks or overlapping transmissions include:

• Habit from Crowded Frequencies: Many radio amateurs are accustomed to operating on crowded bands or repeaters (particularly on 10-meter or 75-meter bands), where any significant pause is perceived as an opportunity for another station to "steal" the frequency or interrupt the conversation.
• Fear of "Stealing" the Conversation: There is a common belief that if an operator leaves too long a pause, another user will break into the conversation, leading to a "quick key" reflex.
• "Rag-Chewing" Mentality: In casual, relaxed conversations, operators often treat radio like a telephone call, aiming for a rapid exchange of information rather than the formal, slow pace of traditional radio procedure.
• Misunderstanding Repeater Operation: Some operators do not wait for the repeater's "courtesy tone"—a sound that signals the repeater has reset and is ready for the next transmission—leading to "doubling" (talking over someone) or premature transmission.
• Unfamiliarity with Proper Etiquette: Not all operators are fully trained in, or consistently follow, best practices regarding break times, which recommend a 5-second pause to allow for emergencies or other stations to join.
• Imitating CB Practices: Some amateur radio operators carry over habits from 11-meter (CB) radio, where fast-paced, high-interference communication is common.

Best Practices to Avoid Overlapping:

• Listen First: Always listen for a few seconds before transmitting.
• Wait for the network to reset: On repeaters, wait for the network to reset before keying up.
• Pause intentionally: Leave a 5–8 second gap between "overs" to allow for break-ins, especially for emergency calls.
• Release the PTT: Fully release the push-to-talk button to ensure the repeater resets properly.

As far as DMR communications over the internet is concerned,  here is some information as to why on should leave a large enough gap between overs:

Networked Digital Mobile Radio (DMR) communications over the internet introduce significant and noticeable latency (delay) due to a combination of digital voice encoding and Forward Error Correction (FEC), and internet traffic delays.

Key Aspects of DMR Internet Latency:

• Operational Courtesy: Because of this latency, operators should wait at least 5 seconds after hearing the end of a transmission before initiating a new one to avoid breaking traffic.
• Transmission Delay: It is recommended to wait approximately 2 second after keying the transmitter before speaking to ensure the connection is established.
• Causes: Latency is introduced by the digital encoding of voice at the transmitter, FEC processing at the receiver, and internet packet routing.
• Technical Performance: Specialized DMR over Internet Protocol (DoIP) gateways can achieve a conversion delay of 9.10 ms, with an average jitter of 1.90 ms and low packet loss.

Operational Considerations:
Unlike analog radios, DMR does not have a "repeater squelch tail." The inherent digital delays mean conversations can feel staggered, requiring disciplined, patient, and structured communication protocols to avoid talking over others and to accommodate the shared nature of networked resources.

 

Enough written.  We all know now what to do from here-on!!

UPDATED: ZS1I WSPR Beacon now active on 10 Meters from Mossel Bay, Southern Cape, South Africa

(Click on the image for larger view.) 

UPDATE 19 April 2026:  The ZS1I WSPR Beacon frequency was changed back to 40 Meters.  The standard 40-meter WSPR (Weak Signal Propagation Reporter) beacon dial frequency is 7.0386 MHz (USB/dial) or 7.0401 MHz (dial). The actual WSPR signals are transmitted in a 200 Hz window, typically placing the center of the transmissions around 7.0401 MHz, using USB mode.

The current WSPR (Weak Signal Propagation Reporter) beacon is set up to transmit low-power signals to monitor global radio wave propagation paths over extended periods, providing data to visualize which radio bands are open and how they are performing

. It's used by amateur radio operators to study atmospheric conditions, test antennas, identify optimal bands for communication, and contribute to a global database of propagation information without requiring manual operation.

I have decided to change the Band / Frequency of the WSPR Beacon currently in operation from Mossel Bay in the Southern Cape.  It was running on the 40 Meter band from  7 October 2025 @ 10h00 SAST to the 15 April 2026 @ 08h00 SAST.  From the 15 April 2026 09h00 SAST it will be transmitting on the 10 Meter band until further notice.

Particulars of the ZS1I Ultimate 3S Beacon active on 10 Meters:

• Call: ZS1I
• Freq. Band: 28.126 000 Mhz
• Dial Freq. :  28.124.600
  
• Band:  10 Meters (28 Mhz)
• Grid:  KF15BT
• Power:  250 mW
• Mode: W-2  (WSPR2)
• Antenna:  EFHW (49:1 Balun)
• TX Period:  Every 10 Minutes
•  Beacon on the air from:  15 April 2026 @ 09h00 SAST
  
•  First Spotter:??????  (Who will it be?)
  

Spotting reports are welcome for 10-meter WSPR beacons, as this band is frequently active and highly dependent on daily propagation changes. WSPR (Weak Signal Propagation Reporter) is frequently used to test HF antenna performance at low power (e.g., 200mW to 5W), with reports uploaded globally. 

How to Spot and Report 10m WSPR

• WSPRnet.org: The primary database for all WSPR spots. Data can be analyzed in real-time.
• WSPR.rocks: A fast, interactive site for searching WSPR data.
• WSPR Watch (iOS App): Useful for monitoring where 10m beacons are being heard in real-time.
• PSK Reporter: An excellent tool to visualize real-time propagation maps and see who is hearing your beacon.
• 10m Frequency: WSPR 10m activity is usually found around 28.1246 MHz (USB dial frequency).

Key Considerations for 10m WSPR

• Propagation: Even when the 10m band seems quiet for voice (SSB), WSPR can show open paths, particularly as the sun moves toward solar maximum.
• Timing: An accurate clock (GPS-synced) is essential, as transmissions start 1 second into an even UTC minute.
• Reporting Frequency: Even very low power (10mW - 20mW) can yield significant DX on 10m.

Finally:  I am looking forward to receive spotting reports of the ZS1I 10m WSPR Beacon active from Mossel Bay, South Africa. 

 

BREAKING: New additions / extensions to the ZS Link Network in the Southern Cape! (Part 3)

ZS1I MMDVM / DMR Repeater issues and how to fixed them.

In the last week or two I ran into some issues regarding the DMR Repeater we are using in the Southern Cape Area.  Now some might one day run into the same issues and I therefor decided to write this article on how to fix the issues.

Here is the issues I experienced:

• DMR Repeater does not except any "calls" from my trusted TYT MD380 and Hytera MD785G radios.
• The Huawei B525 Router used with the DMR Repeater all of a sudden could not access the Internet.
• I used my Windows computer to program the TYT MD380 HT radio in the past.  This time around I could only read the radio but the CPS Firmware refused any other command and would crash as soon as I enter any information.

The above "errors" apart from being frustrating kept me busy for a few days while fault finding.  Now let's look at each "error" individually.

DMR Repeater does not except any "calls" from my trusted TYT MD380 and Hytera MD785G radios.

Background:  The repeater and the two radios worked flawlessly until one morning when I started / rebooted all three items.  Please not all three items was shut down properly the night before.  Never ever hotplug any cables to any of the above radios, hotspot or raspberry pi!!  Well I did not.   I hear some of you say but it must be a problem with the DMR Repeater.  I also thought so and worked  through all the settings of the repeater firmware, calibration and hardware setup.  This took at least two days, working on and off as I find the time.  No luck at all.  It seems if all three radios just decided to be like a stubborn donkey.  Well the next possible fix was to replace the WSPD firmware which I used a the time with Pi-Star firmware.  It might have been a firmware "glitch" as my grandson named software issues.  I took out the WSPD card and re-write a new SD card with the Pi-Star firmware and slotted it into the Raspberry Pi.  No change so I made the assumption that there was nothing wrong with both firmware's.  Just as I side-note using DroidStar was working fine on the DMR Repeater, DMR Bridge and ZS Link Hub.  I looked at Brandmeister under My Devices and every device in used reflected that it was active and working.  ID's matched the devices and Static Talk Groups were set.  All that was left was to go through the CPS files of the 2 RF Radios.  I thoroughly scrutinized the CPS files but could not find any issues.  I started running out of options but somewhere there is a problem and that needs to be fixed.

The error / errors:  If I could get one radio to work the other one would be fixed instantly.   I needed to look deeply into the error issue.  I used the TYT MD380  Radio to label the error.  Error = The radio would TX for a short period and then a error beep would sound.  The LED on the radio goes red when TX'ing but then alternate between red and green.  The DMR Repeater screen stays in the default display while the RX and TX radio LED's will light up as it should.  Nothing else happens and this indicate that the MD380 radio does not open the repeater.  I hear you shout Talk Group, Color Code, Time Slot, Calibration, TX and RX Frequency, RX Group List and Zone.  Well checked all of that with no joy!

To solve the issue:  The solution to the problem was quite easy and mainly overlooked.  It was a DMR ID issue that was solved by just deleting two numbers.  Let's look at the solution.  I use a 7 number DMR ID and for the purpose of this article I will use 655xxxx.  Let's to to Configuration in Pi-Star.  Move down to General Configuration and find CCS7/DMR ID. The ID must be 655xxxx (7 Digits).  At the same time make sure that your Hotspot Security Password in DMR Configuration is correct.  Also ensure that in DMR ESSID there is no ESSID.  It should look like this 655xxxxNone.  Now click on Apply Changes and wait for the screen to return.  Once the changes were set go to the top of the page and look for Expert.  Click on Expert.and then on MMDVMHost.  Under the General Tab ensure that the Id is the seven number 655xxxx.  Now go down to the DMR Tab and this is where my error originated.  Go to Id en  make sure that you enter the 655xxxx number.  For some rime or reason my Id looked like 655xxxx05.  Do not ask me where the two last digits came from. These two numbers created the following number in BrandMeister under My Devices  = 655xxxx05 which displayed a green hart as well as 655xxxx which also displayed a green hart.  In other words this caused all sorts of mayhem albeit the DMR Repeater not working as it should.

 

I removed the 05 and rebooted the repeater and wallah the repeater came to life and work as it should. As mentioned before "The solution to the problem was quite easy and mainly overlooked.". The error hiding away until I found it. I am now able to use both DMR Radio to talk to the repeater without any hassles.  The repeater can also be linked to the ZS Link Hub providing a further extension of the ZS Link Network.  With this problem sorted let's move on to the next "glitch".

(Click on image for larger view.)

The Huawei B525 Router used with the DMR Repeater all of a sudden could not access the Internet.

Okay I must admit that on of the computer I  use in the Shack is rather ancient.  It runs Window 7.  Now I mainly use this computer to monitor nodes, repeaters, bridges etc.  I have 3 routers in my shack running different equipment on them. The Huawei B525 Router is used with the DMR Repeater.  The router is setup correctly and was working correctly when all of a sudden I would receive the following error message after a reboot of the machine.  

"no internet access DNS server isn't responding"

Now I did not have any time to go into a detail setup / search through the firmware of the computer.  I found the following solution to the issue.

To fix "DNS server isn't responding," restart your router and modem, clear your browser/system cache, and try flushing DNS via Command Prompt (ipconfig /flushdns). If issues persist, switch to a public DNS server (like Google’s 8.8.8.8 and 8.8.4.4), update network adapter drivers, or temporarily disable firewalls/VPNs. 

Quick Fixes for DNS Errors

• Restart Hardware: Power-cycle your router and modem (unplug for 30 seconds).
• Flush DNS Cache: Open Command Prompt as administrator and type ipconfig /flushdns.
• Switch DNS Servers: In network settings, change IPv4 DNS to 8.8.8.8 (Preferred) and 8.8.4.4 (Alternate).
• Disable Third-Party Antivirus/VPN: These can often block DNS requests.
• Check Physical Connections: Ensure Ethernet cables are secure, or try a different cable.
• Update/Reinstall Network Adapters: Open Device Manager, find your network adapter, and check for driver updates.
• Disable IPv6: Sometimes switching to IPv4-only fixes connectivity.

(Click on image for larger view.)

Needless to say the only solution that worked for me was the following: (See image above) 

Go to Control Panel and select Network and Internet - Network and Sharing Center.

Click on Local Area Connection

Window will open - Local Area Connection Status  Window will open - Local Area Connection Properties

Click on Properties - Double click on - Internet Protocol Version 4 (TCP - IP4)

Internet Protocol Version 4 (TCP - IP4) Properties window will open.  

IP Address obtain Automatically must be selected

Select:  Use the followng DNS Sever Addresses

Enter the following addresses:

Preferred DNS Server:  8.8.8.8.

Alternative DNS Server:  8.8.4.4.

Click OK and OK and Close

Reboot the computer and after restarting your Internet will be back up and working!!

Note:  Yes there is other solutions to this problem but I used the above that was easy to setup and implement. 

(Click on image for larger view.)

I used my Windows computer to program the TYT MD380 HT radio in the past.  This time around I could only read the radio but the CPS Firmware refused any other command and would crash as soon as I enter any information.

Onto the final "glitch".  I use stock standard firmware and cable to program my TYR MD380 HT Radio.  This time around I received an error in Chinese stating that Microsoft will be looking for a solution.  Now we all know running a Window 7 machine will result in no feedback, response or support.  I expected the problem to be driver related and removed the old drive and install the latest version.  Well still no joy.  Scratching around the Shack I found my old Windows XP laptop which already had the CPS and driver installed.  Success on the first try.  The radio was read and write with the necessary changes without any issues.

Moral of the story -  Never get rid of your old computers.  They can help you out when the newer one's are stubborn and "glitchy".

With the three issues solved the DMR Repeater is now operational in the Mossel Bay Area.  Unfortunately the cooling fans are making quite a bit of noise and will have to be replaced.  I ordered two fan speed controller and as soon as they arrive I will fit the new fans on the repeater.

Finally: I trust that this article would be of some benefit to those who might experience the same issues.  For many this might be general knowledge but for others it might be helpful.  I have quite a few "tricks up my sleeve" in the future regarding this repeater.  If you interested in how one can use this repeater to it's full potential then do not miss Part 4 and Part 5.  Even better come and join in the fun!