Image: Flow Chart RF Radio Link (Click on image for larger view.)
For a while now I have been thinking about a KISS method to link the Aasvoëlkop Repeater near Albertinia to the ZS-HUB in Mossel Bay when the Internet is down due to loadshedding or any other outage. Instead of complaining or sitting around waiting for the re-connection of links when the Internet is down I decided to establish a VHF RF Radio Link to the Aasvoëlkop Repeater near Albertinia. This link is not a replacement for any other Internet connected links to the Aasvoëlkop Repeater but will serve as an emergency radio link. We must remember that when the Internet is down Echolink will also fail but this is not the case with AllStar. Although we still lose long distance link connections when the Internet is down, AllStar will still be functional locally. We use to lose all connections to the Aasvoëlkop Repeater during Internet outages. This left many stations in the cold until the Internet connections are re-established. This will not be the case anymore.
The establishing of the VHF RF Radio Link in Mossel Bay has the following advantages and disadvantages:
Advantages:
1. During Power or Internet outages we will still have a fully functional connection to the Aasvoëlkop Repeater.
2. The RF Link provides a wider coverage area in the Southern Cape. We can now reach areas in Mossel Bay that previously did not have repeater coverage due to topographic obstacles.
3. The RF Link can now be used by radio amateurs who previously had marginal access to the repeater with scratchy or "rain" on their TX or RX signal.
4. The RF Link is using the KISS method. It is simple and easy to use the link and you have two ways to access the Link.
5. No extra equipment was needed to setup the VHF RF Radio Link. The current ZS1I 145.550 Mhz RF Link equipment was used. Software changes however had to be made.
6. With the press of a button I can change to either the ZS1I 145.550 Mhz RF Link or the 145.625 Mhz Aasvoëlkop Repeater RF Link.
7. It will be quite simple to add a UHF RF Radio Link to the current setup if there is a need for such a link.
8. Radio Amateurs can now use lower radio power output to excess the Aasvoëlkop Repeater through the VHF RF Radio Link.
9. All the other broadcasting options is still available as before using the KISS method. I did however disconnect telemetry and courtesy tone options to prevent the Ping-Pong effect between the repeater and the RF link.
10. You will not hear the Aasvoëlkop repeater "tail" on the RF Radio Link. I setup AllStar to eliminate the repeaters squelch tail.
11. There is very little latency if any between the ZS1I HUB and the Aasvoëlkop Repeater. However there will still be latency issues if connected to the other nodes when the Internet is up and running.
12. The RF Link is open for use by any radio amateur. Please note that although there is no indication on AllStar or Echolink that the link is active, the only way is to put out a call on the HUB, 145.625 Mhz or the DMR Bridge. I am currently looking at a possible announcement when the RF link is active.
Disadvantages:
1. Not all areas in the Southern Cape will be covered by the VHF RF Radio Link as is the case with any repeater.
2. Certain telemetry announcements will not be active when the RF link is active.
3. This VHF RF Radio Link is working but it is not the most ideal way to setup a direct RF Radio Link. Obviously the most ideal situation would be to have an AllStar Node and Internet connection at the repeater site, but due to road and terrain access issues this is not possible.
4. This VHF RF Radio Link will not be active 24/7. It will only be available during Emergencies, Internet Outages, Power Failures and when the need arise to use the link for some kind of event or purpose.
5. Currently there is no method to remotely disconnect the link via DTMF, or Wi-Fi. I am working on a solution in this regard. Update to follow soon.
Image: RF Radio Link and backup power (Click on image for large view.)
How do I use the Aasvoelkop RF Radio Link?
Using the RF Radio Link to the repeater becomes nothing more than a normal user of the repeater. You use the RF Radio Link as you would when you use the Aasvoëlkop repeater. You use your radio to transmit and receive as if the RF Radio Link is the repeater. Option 1 underneath is the frequencies you use.
Refer to the SCP ZS-Link Network Flow Chart above to get a clearer understanding.
We need to make a few minor changes to our HT, Mobile or Base Station radio frequencies. Lets first look at the frequencies used by the repeater and then to frequencies use by radio amateurs that would like to access the Aasvoëlkop Repeater.
Aasvoelkop Repeater Frequencies
RX = 145.625 Mhz 88.5 Hz CTCSS
TX = 145.025 Mhz 88.5 Hz CTCSS
Radio User (Option 1): Radio Frequencies (Program these frequencies in your HT, Mobile or Base Station radios)
RX = 145.625 Mhz 88.5 Hz CTCSS
TX = 145.025 Mhz 88.5 Hz CTCSS
Radio User (Option 2): Radio Frequencies (Program these frequencies in your HT, Mobile or Base Station radios)
RX = 145.025 Mhz 88.5 Hz CTCSS
TX = 145.625 Mhz 88.5 Hz CTCSS
Note: Option 2 must only be used if you are in reach of the ZS1I QTH / Tower. To setup CTCSS refer to your radio's users manual.
For those who would like to setup a VHF RF Radio Link to a repeater, this is how I did it.
I am not going to explain how to setup/connect the AllStar software and radio hardware using a Raspberry Pi and a Motorola Radio. Google and YouTube are your friends here. From here-on I will provide the changes I made to some AllStar files to get the link to work properly.
Important Note: I used the HAMVOIP Firmware. I do not know if the ASL3 Firmware will work to setup a remote RF link. A Motorola Radios M100 is used as the link radio.
Image: AllStar Admin Menu List (Click on image for larger view.)
Image: simpleusb-tune-menu (Click on image for larger view.)
ALLSTAR Settings / Changes:
1. Simple-Tune-Menu Settings
Log in via Putty or MobiXterm
In the Admin Menu List go down to Run simpleusb-tune-menu Application
Click on it.
Simpleusb-tune-menu will open
Go down to M) Change RXONDELAY value (currently "-100")
Enter M and set this value to -100
Rxondelay delays the valid COS signal and is used to stop cyclic keying or ping-pong which can sometime happen. If you bring up simpleusb-tune-menu and select the "V" view mode. You can see both the COS input and COS composite displays. To understand how rxondelay works set it to some high value like 20 or 400ms. When you transmit to your node you will see the COS input immediately go keyed and the 400ms delay of the composite. Setting this value to high would cutoff the beginning of a transmission as it delays the actual COS beyond the real COS signal. The default is 0 and this would be appropriate in most all cases except in the case of the Aasvoëlkop Repeater with a fairly long squelch tail. In my case -100 did the trick.
After entering the value go to N) Change RXAUDIODELAY value (currently "10")
Enter N and set this value to 10
Rxaudiodelay is primarily used for squelch tail elimination. It delays the audio in a buffer so that a drop of COS can cutoff a portion of the audio before the COS drops thus eliminating the tail of the transmission where a squelch crash would take place. Since all radios are different this value is adjustable. Valid values are from 0-24 in 20ms increments. Typical values in most cases would range from 5-10 or 100-200 ms. If is obviously not mandatory to use this, some people actually like squelch tails. The default is 0. If you have a way to monitor your node through another node or maybe iaxrpt you can listen when you drop TX on the node you want to adjust and move this value up until the tail is gone. Unless the tail is unusually long you should be able to eliminate it.
Now lets write the changes to the simpleusb.conf
Select W) Write (Save) Current Parameter Values
Enter
When "please enter your selection now appears" select 0 Exit Menu and Enter
Settings in the menu is now complete.
Image: rpt.conf file (Click on image for larger view.)
2. Repeater / Simplex Settings (rpt.conf)
Go back to the Admin Menu List screen
Select 9 Start Bash Shell interface
Enter
# cd /etc/asterisk
Enter
[root@allnode asterisk]# sudo nano rpt.conf
Enter
Go to Repeater / Simplex Node Settings
Look for duplex = 1
Change the 1 to 0
duplex 0
This means half duplex with no telemetry tones or hang time. Special Case: Full duplex if linktolink is set to yes. This mode is preferred when interfacing with an external multiport repeater controller.
We are done!
Press Ctrl +X
Yes
Enter
Changes will now be saved
Restart Asterisk Server in Admin Menu List
Image: rpt.config file - turn off connect and disconnect announcements.
Time to turn off link connect and disconnect announcements
When running a link network we need to turn off those ridiculous connect and disconnect announcements which can last a long time and also interrupt the use of the link system.
The following commands need to be edited to get rid of the annoying connect/disconnect telemetry messages.
Go back to the Admin Menu List screen
Select 9 Start Bash Shell interface
Enter
# cd /etc/asterisk
Enter
[root@allnode asterisk]# sudo nano rpt.conf
Enter
Now look for:
holdofftelem=1 (Disable courtesy tones) ( 0 = default, 1=Disable)
telemdefault=0 (Do not make announcements)
; 0=voice telemetry off
; 1=voice telemetry on
; 2=only your telemetry actions
Press Ctrl +X
Yes
Enter
Changes will now be saved
Restart Asterisk Server in Admin Menu List
Your RF Radio Link will now be up and running!
Now back to the SCP VHF RF Radio Link. Whow what a name for a single rf radio link but we need to differentiate between the links running in this area on the ZS Link Network.
Summary:
1. The link is currently active on a test basis daily from 08h30 to 16h25 until further notice.
2. The link will not be active 24/7 in the future.
3. This link will be active during Emergencies, Internet and Power outages.
4. This link is not a substitute for any of the other links currently active in the Southern Cape Area.
5. If you get no response on the ZS1I 145.550 Mhz RF Link then switch to the 145.625 Mhz Aasvoëlkop Repeater RF Link and call.
6. Updates to follow in a future posting regarding the working and feedback relating to the RF Radio Link.
Finally:
Enjoy using the Aasvoëlkop VHF RF Radio Link another valued addition to the SCP Link Network, brought to you by the Southern Cape Link Network Group.
