Category Archives: DMR

DMR: Pi-Star Users – Change your default password ASAP

Attention Pi-Star (digital hotspot Raspberry PI operating System) Users:

PLEASE change your default passwords before exposing your pi-star to the internet. As in, GO DO IT NOW.

It takes less than 2 minutes for a hacker to query for open-to-the-internet pi-stars (CLICK HERE FMI), randomly pick one, use the default creds, and get a remote SSH shell into your home network. You’re basically locking your front door but leaving a window open. Once inside your home network, the hacker can sniff your traffic, spoof your identity, and do a whole host of other stuff. Getting into a network is the hard part, and you’re leaving it wide open.

Oh also, since your callsign is on it, a hacker can not only do stuff from your home internet, but knows where your home is and can impersonate you by name!

This only affects you directly if you have the “Dashboard Access” or “SSH access” set to public, but you should change the password either way.




DMR: NY Metro and TG-311037

The following is a kind offering by Bernie NY4Z to adjust the following DMR repeaters in the NY Metro area. Our thanks to Bernie for this helping hand.

Now that you have gotten your new site and TG internet connectivity I have made changes to accommodate your new talk group 310037. I have set you up as a PTT with a 15 minute timer (TS1) on the machines below which should give you 100 plus miles of coverage in most directions around NYC with a mobile radio and many of these areas have good HT coverage.

GW Bridge, NY N2NSA 443.8875 + 5.00 Color Code 1
Time Slot
#1 – Group Call TG 444 NY Metro System Wide – FT
#1 – Group Call TG 333 = DMR Plus Reflector 4604 (NY Reflector) PTT
#1 – Group Call TG 310037 BRARA (Boca Raton ARA) Local Talk Group -PTT
#1 Group Call TG-9998= Parrot audio test (PTT)
#2 – Members Only private Talk Group

White Plains, NY NY4Z 442.10625 +5 MHz Color Code 3
Time Slot
#1 – Group Call TG 444 NY Metro System Wide – FT
#1 – Group Call TG 333 = DMR Plus Reflector 4604 (NY Reflector) PTT
#1 – Group Call TG 310037 BRARA(Boca Raton ARA) Local Talk Group -PTT
#1 – Group Call TG 347639 Disney – PTT
#1- Group Call TG 31660- Ocean county NJ (PTT)
#1 Group Call TG-9998= Parrot audio test (PTT)
#2 – Members Only private Talk Group

Glen Oaks , NY WB2WAK 438.51250 -5 MHz Color Code 1
Time Slot
#1 – Group Call TG 444 NY Metro System Wide – FT
#1 – Group Call TG 1 = World Wide -PTT
#1 – Group Call TG 3 = North America – PTT
#1 – Group Call TG 347639 Disney – PTT
#1 – Group Call TG 13 = World Wide English – PTT
#1 – Group Call TG 3172 = NE / Regional – PTT
#1 – Group Call TG 310 = Tac 310 – PTT
#1 – Group Call TG 311 = Tac 311 – PTT
#1 – Group Call TG 333 = DMR Plus Reflector 4604 (NY Reflector) PTT
#1 – Group Call TG 3110037= BRARA (Boca Raton ARA) Local Talk Group -PTT
#1 – Group Call TG 31660 = Ocean county NJ- PTT
#1 – Group Call TG 9998 = Parrot , Audio Test Server – PTT
#2 – Members Only private Talk Group

Mt. Beacon, NY NY4Z 441.450 + 5. MHZ CC7
Time Slot
#1 – Group Call TG 347639 Disney – FT
#1 – Group Call TG 9998 = Parrot, Audio Test Server – PTT
#1 – Group Call TG 9 Local Talk Group – FT
#1 – Group Call TG 31361 = Upstate NY – PTT
#1 – Group Call TG 333 = DMR Plus Reflector 4604 (NY Reflector) PTT
#1 – Group Call TG 310037 BRARA (Boca Raton ARA) Local Talk Group -PTT
#2 – Group Call TG 444 NY Metro System Wide – FT

Manahawkin , NJ K2HR 445.4250 – 5 MHz Color Code 3
Time Slot
#1 – Group Call TG 444 NY Metro System Wide – FT
#1 – Group Call TG 347639 Disney – PTT
#1 – Group Call TG 1 = World Wide – PTT
#1 – Group Call TG 3 = North America – PTT
#1 – Group Call TG 13 = World Wide English – PTT
#1 – Group Call TG 3172 = NE / Regional – PTT
#1 – Group Call TG 123 = UA English 2 Talk Group – PTT
#1 – Group Call TG 310 = Tac 310 – PTT
#1 – Group Call TG 311 = Tac 311 – PTT
#1 – Group Call TG 333 = DMR Plus Reflector 4604 (NY Reflector) PTT
#1 – Group Call TG 3134 = New Jersey StateWide – PTT
#1 – Group Call TG 9998 = Parrot , Audio Test Server – PTT
#1- Group Call TG 31660- Ocean county NJ (PTT)
#1 – Group Call TG 310037 BRARA (Boca Raton ARA) Local Talk Group -PTT
#1 – Group Call TG 9 Local Talk Group – FT
#2 – member only private Talk Group

You are welcome to share this information if you desire.

Bernie NY4Z

DMR Microwave Update

Today 25-Nov-2019 Jerry W4BFL, Lew W4LEW, Jerry’s son Anthony KM4MFX and Grant W4KEK teamed up to address improving the existing setup at  the site which were:

  1. Remotely control the repeater settings and controls
  2. Improve data transfer rate between the repeater site and FAU

The following are some picture of the repeater site closet

This is the current state front look of the DMR repeater

These are some of the controls that help enable access remotely

Another view of the repeater and power supply

The 2m duplexer cans that are now used as band pass filters given we have split antennas. This arrangement resolves the intermod and desensig issues.

This is the 2m analog repeater with various pieces of gear on top.

Jerry W4BFL, Anthony KM4MFX, and Grant W4KEK discussing and accessing the repeater

Father and son debating next steps.

The front panel with various ethernet connections to one of the control devices

In maintenance and equipment room of the SS building where Anthony and Grant are working.

Another picture of our DMR machine.

After the team was ready, they split up into two groups

  1. At the repeater, finish DMR configuration to remotely control machine
  2. On the roof, swap out current microwave dish for an upgraded version
  3. One the roof, adjust dish for better reception 

Below are some photos of roof work and view.

Facing west toward Parkland. The structure on the right houses an assortment of cell equipment and has warning signs not to wander into that area.

This is the same cell housing area and the antenna is now used for 2m analog transmission. The solution to the intermod was to split the transmission from reception. This antenna was already in place, we were not using it but it was repurposed to solve a problem.

Another view facing north west toward The Shack at the West Delray Park

This view is of the transmission antenna on the left and the reception bow-tie antenna on the right. The pipe in the middle is not currently used.

These are one of our best investments: commercial grade tow-die dipole antennas. The 2m is on the left and the 70cm antenna on the right.

This is the 70cm bow-tie dipole antenna on a day that is just amazing to be on the roof. The elements face west.

Another view on just an amazing day.

This is the 2m transmission repurposed antenna that is used to solve our intermod issue with our gratitude to Erik Rodriguez KF4LZA who worked on the duplexers. He repurposed the 2m duplexers to act as input filters from the bow-tie antenna.

The connectors at the 2m repurposed antenna.

Another view and notice the 2m transmission feed line that was painted probably hardline.

Looking up at the top of the 2m transmission antenna.

The very top. The connectors had to be replaced when Erick was on site.

This is the base of the 70cm antenna feedline.

This is the base of the 2m assembly and pole holding the antenna. The chrome moly pipe is hardened and will sustain hurricane winds.

Looking at the transmission antenna on the left and the reception antenna on the right.

Looking north-north east toward downtown Delray Beach. The green water tower in the distance near the middle of the picture is the Delray maintenance facility.

This north west shot is looking directly at The Shack.

70cm antenna facing west with Boca to east in background.

The current microwave dish facing FAU engineering building roof. RT95 is in background and this is about 10 stories high.

An up close view of the current dish.

This is the white protection unit.

Taken from the microwave dish facing north, another view if the 2m transmission antenna secured to a pipe.

View of the top of that 2m transmission antenna.

2m bow-tie antenna elements.

Middle element

Bottom element

Another view of the base of the 2m reception antenna.

Upclose of that same water tower in Delray.

Getting ready to replace the current dish with an upgrade more sensitive dish.

Doing the disconnect work.

All hands on deck.

It’s off and what no signal. Had fun with Anthony when I had my Tyt380 UV and set it to GCARA PMB parrot and made a call. Yes, it echoed back and Anthony’s look of puzzlement was interesting. I did not get that picture only exists in my mind.

Setting up the right driver heads.

This is the upgraded dish with bracket begin removed because it was too small. Note the adjustments for the 3 axis for the dish.

Looking at downtown Boca.

Getting the new dish up.

Team work of course. Takes many hands

Yes team work.

This is a cell configuration that is about 3 feet from our dish. Notice south bound RT95 ramp traffic

Anthony looking at that naked lady sunbathing.

This is the view he’s looking at.

On the distance is the FAU engineering building and dish on the roof.

The assortment of lines feed that cell near our dish.

Close, very close.

Grant in focus.

Ethernet feed and connector about to be plugged into the horn.

Note the plastic water tight cap the cable passed through.

Now plugged into the horn.

Good image of the horn with ethernet connected.

Finished job. Now to make it work. May adjustments and trials and errors.

What is the end result?

  1. The DMR repeater can be remotely controlled
  2. FAU to SS dish from 39 mbps to 84 mpbs
  3. New dish was replaced with old dish because it did not work as needed

Hope you enjoyed this and our many thanks to:

  • Robert Eng W1ENG for enabling us to acquire this highly sought repeater
  • Jerry Zaza W4BLF for his many hours and time off from work to make this happen. There are so many things he as done for our benefit we’ll never know, all of which enable us to have a better environment and enjoy our hobby
  • Lew  Lehman K4LEW our repeater trustee for enabling us to access the repeater location and ensure the 2m machine is working as needed.
  • Art Lewis WA4VSK for partnering with Lew and Erik to get the 2m issue addressed. Yes Art is one of our key contributors like Jerry and has spent countless hours at the site and resolving HF issues.
  • Erik Rodriguez KF4LZA for providing his technical expertise and analysis equipment to partner with Art and Lew in solving the 2m issues.
  • Anthony Zaza KM3MFX and Grant Baron W4KEK for proving their youth and expertise and helping hands getting the project complete.

And, yes have probably missed some folks. Will add them as i discover their contribution.


John.C N1QFH

DMR: Adding New TG and Channel

Adding a talkgroup and a channel to your codeplug using the software for your radio

After opening your codeplug software and reading your radio’s codeplug into the software save the file to your computer as a backup just in case then go to the talkgroup section. Scroll to the bottom and add the new talkgroup to it by clicking on the empty line and then entering the talkgroup number and assign a name to it and set it as a group call.

Adding a channel to your codeplug

Go to the channel section of your codeplug and scroll to the bottom and add the new channel to it by clicking on the blank line and then entering the needed information to cause it to be usable such as the rx frequency, the tx frequency, that it is digital, the color code for the repeater or hotspot, the time slot and the talk group name you want to access. Now go to the zones section and add the channel to the zone or zones you want it in. You have now added all the information necessary to be able to access the new channel from a zone or zones on your radio.

Write the new codeplug to the radio and check it out. If all went well and you can access the new channel and talkgroup you entered save the new codeplug file to your computer as your new codeplug.


DMR: Choosing a pi for your pi-star hotspot

Bud Talbot W0RMT

An important question to consider when building a pi-star based hotspot is what version of raspberry pi to use. You have three basic form factors to choose from: the zero, A+, and B+. The pi-zero is the smallest of these three, followed by the A+, and then the B+. The latest versions are the pi-zero W (or WH, which just has the header soldered on), the pi-3 A+, and the pi-3 B+. Other important factors to consider besides size are power consumption (very important for portable setups), boot time, wireless connection strength, and time required to switch configurations.

pi Specs

First let’s look at some published specifications for each of these models. Below is a nice chart from

From this chart, you can see that both the pi-3 A+ and pi-3 B+ have quad core processors clocked at 1.4 GHz. The difference between these two computers in terms of system resources is the RAM: the pi3 A+ has 512 MB while the pi-3 B+ has 1 GB. Note that the A+ form factor also lacks the RJ45 ethernet port, and only has 1 USB port. Neither of these is really a huge limitation for a hotspot in my opinion. That said, I do like to connect my pi-3 B+ based hotspots directly to the ethernet when available. The pi-zero is much smaller, but also has only a single core processor clocked at 1 GHz with 512 MB or RAM. So we can expect it to be slower in terms of performing operations. But for that tradeoff, you should see significantly less power consumption. Another important difference is in the WiFi: the A+ and B+ support both 2.4 GHz and 5 GHz 802.11 b/g/n/ac protocols, while the pi-zero only supports 802.11n over 2.4 GHz. This is likely to be an important factor as well.

Testing Procedure

In order to look more deeply at power consumption, I set up a test where I compared the three different raspberry pi options (zero, A+, and B+) using the same mmdvm hat (an N5BOC simplex board) and the same instance of pi-star (v 4.0 RC3) installed on a micro SD card (Patriot class 10 16 GB), and using the same power supply.

I then measured voltage (V) and current (I) over time using a small, inline USB meter (the UM25C). One nice thing about the UMC is that it interfaces with a PC over bluetooth so that you can record V and I versus t and view a graph and output data on the PC. This is a screenshot of testing for the pi-zero:

For each of the raspberry pi models tested, I ran three trials where I booted the pi and let it run for 15 minutes. I set the pi-star image up for D-STAR, and used the voice announcement as my “ready indicator for boot time.” I recorded the following parameters:

  • Boot time
  • 15 minute capacity used (in mAh)
  • 15 minute energy used (in mWh)
  • steady state voltage and current
  • pi load averages at 15 minutes (1’, 5’ and 15’ loads- see this linkif you’re not familiar with these metrics. Remember the pi-zero has a single core while the A+ and B+ have 4 cores)
  • Temperature (open case) after 15 minutes. Note that future testing should probably be in closed case which is more typical of operation. But that also introduces many more variables for each form factor (e.g. air space in case, ventilation in each case, etc).
  • Wifi signal strength (in dBm – see this linkif you’re not familiar with this measure). I measured this as signal strength received by my Ubiquiti networks access point, as read through the Unifi interface. For VoIP protocols, we really need at least -67 dBm. A lower value might work in some situations, but we’d like to see this greater than -67.



pi-zero W

pi-3 A+

pi-3 B+

Trial 1

Trial 2

Trial 3

Trial 1

Trial 2

Trial 3

Trial 1

Trial 2

Trial 3

Boot time











15’ Capacity used (mAh)










15’ Energy used (mWh)










Steady state Voltage (V)










Steady State current (A)










Max current (A)




1’ pi load (@15’)










5’ pi load (@15’)










15’ pi load (@ 15’)










Temp- open case (@ 15’) (°C)










Wifi signal strength (dBm)











So what’s the conclusion? First, let’s look at the data to identify some notable differences.

  • Boot time: the pi-zero is about 20 s slower than the pi-3 A+ and B+
  • Power consumption: the pi-zero uses the least power, but the A+ doesn’t use much more. The B+ is a hog by comparison.
  • Maximum current on boot: again, the B+ has the largest, but it is still under 1 A. This surprised me, as I expected maximum current draw to be greater.
  • Operating temperature: the A+ has the clear edge here. It’s not working as hard as the pi-zero (reference the load averages) and it’s larger board may dissipate heat better.
  • Wifi signal strength: the zero really lags in this metric. The A+ and B+ have a 10x stronger wifi signal. This is a big deal.

Bottom line: I think the pi-3 A+ is probably the best in terms of boot time, low energy consumption, operating temperature, and wifi signal strength. And in terms of form factor, it’s not much larger than a pi-zero. I think that once we see some good case options for A+ based hotspots, we’ll notice a proliferation of ham hotspots built on the pi-3 A+. I know I’ll be migrating mine over to the pi-3 A+ from the pi-zero’s. I do think the pi-3 B+ board still has great utility in situations where power consumption is not an issue, like on the desktop in the shack where you are likely plugged into mains power and might want to connect to the network via ethernet.

Thanks for reading.


DMR: Update to the AnyTone radios

Here are the instructions for applying the vocoder update to the AnyTone radios.

There is a new Firmware update posted for the AnyTone 878 named vn 1.14. within this update there is an update for the Baseband IC 3258 chip. This update also applies to the AnyTone 868 but has not been published on the 868 update site. The update applies changes to the vocoder and hopefully fixes some issues with coding and decoding of the digital signals. In order to get the update go to the following link CLICK HERE

If you have an 868 only do the baseband update from this file.The rest of the updates do not apply to the 868. You have to unzip the file and save it somewhere on your computer. Go to the baseband update folder and read and follow the instructions carefully to apply the update to the chip.


DMR Repeater and Antenna Installation Status

Summary: The new BRARA DMR Repeater and UHF Antenna were installed on Wednesday, July 31, and is operational for local communications on 442.875 MHz +5 MHz Offset (previous UHF repeater frequencies) with Color Code 1 (CC-1), Time Slot 2 (TS-2), Talk Group 311037. Connection to Brandmeister is still pending (non-operational).

Details: On Tuesday, June 30, the Motorola SLR5700 DMR Repeater was programmed by Jerry Zaza. The repeater is Brandmeister repeat number 311037 and the local talk group was programed to be 311037. He tested local communication between two handhelds on TS-2 TG-311037, tested the connection to Brandmeister with the Ethernet connection, made sure the repeater would work locally even without an Ethernet connection, and made sure the repeater was broadcasting an analog CW ID every 10 minutes. After testing, which required a low power setting, he set the power setting back to maximum. Robert Eng picked up the DMR repeater and the Ethernet Microwave Antenna from Jerry for installation the next day.

On Wednesday, July 31, at 9:00 AM, Art Lewis, Gerry Gawaldo, and Robert Eng met at the BRARA shack and picked up the new UHF 4-element folded dipole antenna and transported it to the repeater site.

On Wednesday, July 31, at 10:00 AM, the team of Art Lewis, Lewis Lehman, Gerry Gawaldo, Grant Baron, Pablo Solsona, and Robert Eng met at the repeater site at the One Park Place building at the northwest corner of Yamato Road and I-95. The following was performed:

1. The new UHF antenna, tools, and the Microwave antenna were lifted by rope to the roof (top level) of the building. They had to be roped up because it was impossible to bring them up the vertical ladder which leads up to the roof.

2. The old UHF repeater antenna was removed. The mounting nuts were relatively easy to remove (ie they were not frozen).

3. The new UHF antenna was installed in same place as the old antenna using the existing hardware. SWR of new antenna was checked with a Rig Expert AA-600 Antenna Analyzer. SWR was around 1.2. The new antenna was connected to the existing coax cable. The new antenna has a male N connector and the existing cable had a female N connector. Connection was sealed with black tape.

4. The existing Ethernet cable was identified and tested with an Ethernet Cable tester. All 4 pairs and the shield of the cable tested OK.

5. Internet Microwave Antenna was mounted on the bottom of the UHF antenna mask slightly above the edge of the wall around the roof. Ethernet cable was attached. Antenna was leveled and pointed towards FAU.

6. Old UHF antenna and tools were lowered from roof using rope.

7. DMR Repeater was installed in repeater rack. Repeater transmit and receiver ports were hooked to duplexer. The transmit port were both N connectors but the receiver port required a female N to male BNC adapter (repeater receiver port is a female BNC).

8. Ethernet cable from Microwave Antenna was hooked to POE power supply, then cabled to an Ethernet Switch. The LAN1 port of the repeater was also connected to the Ethernet Switch.

9. Repeater was powered on. Gerry Gawaldo had a DMR handheld programmed for CC-1, TS-2, Talk Groups (TG) , 91 (WW) , 93 (NA) , and 311037 (BRARA). Found that Talk Groups 91, 93, 311037 made the repeater respond (transmit LEDs on front panel of repeater lit) but TG-9 had no response. Do not test actual voice communication because we only had one DMR radio.

Sometime on Wednesday afternoon, it appeared the repeater stopped working. Robert Eng could not get his CS800D at home to handshake with the repeater (getting Call Failed message) and Gerry Gawaldo could not longer contact the repeater with the same radio he used when we tested the repeater after installation.

On Thursday, August 1, at 11:00 AM, Art Lewis, Lewis Lehman, and Robert Eng went back to the repeater site to check the DMR repeater. The red alarm LED was lit, and it obviously had shutdown. Added a right angle adapter to the top of the repeater rack to relieve strain on coax going to antenna. Measured transmit power of DMR repeater – was about 50 watts when keyed up. Measured SWR of antenna plus coax (where coax connects to duplexer) and SWR was 1.3. Tested communication between two DMR handhelds on TG 311037 both near the repeater and outside in parking lot and voice communication works OK.

The Internet connection portion at the repeater site should be complete (other than the antenna aiming may need to be refined). The FAU portion of the Internet connection still needs to be completed in order for the connection to Brandmeister to work.

If I forgot or misstated something, please feel free to correct me. As one gets older, the memory starts to fail.

A million thanks to everyone that helped with this effort to get the DMR repeater up and running. Greatly appreciate your time, effort, and expertise.


Robert Eng W1ENG


DMR: Pi-Star – How to upgrade vn4.1 rc from earlier versions

How to upgrade to the latest vn4.1 rc from earlier versions of Pi-Star. The new version is designed to work on all versions of the RPI boards from a Pi zero up to the latest Pi 4 boards. It became necessary due to the release version of Linux changing and the new features of the new Pi 4 boards.

First you must backup your current pistar configuration. In order to then upgrade you will have to download from the pistar website the latest version ( beta version as of now ) of the software. You will then have to reformat an SD card and then burn the image to the SD card. After that is done copy the backed up configuration zip file to the root directory of the SD card. At this point you can place the SD card into your hotspot and boot it up. It will take several minutes for the hotspot to complete the upgrade and then you will be able to log into it. If you had changed the password from raspberry to something else it will be returned to raspberry as that is one of a few fields that is not saved in a backup. At this point do an SSH login in and do a sudo pistar-upgrade to load that latest upgrades. After that is done do a sudo pistar-update to get the latest updates to the Linux and any pistar binaries that have been updated since the image file was created. Now you can look at the fields on the admin page and the configuration page and make sure any fields you changed but were not backed up are made correct.


DMR: Pi-Star Firmware upgrade for mmdvm HS hat flash by Al Af4FA

Revised: 23-July 2019

If you have a different modem board you need to adjust the commands to those for your particular board using the list at the bottom.

– open your pi-star admin dashboard in a web browser
– go to configuration
– go to expert
– go to SSH-Access
– log on (user pi-star + your password)
– type “sudo service mmdvmhost stop” press enter
– type “sudo pistar-mmdvmhshatflash hs_hat” press enter
– confirm by pressing any key (last chance to back out by pressing CTRL-C here)
– wait till you get the message that flashing is complete,then press any key to reboot
– open your pi-star dashboard in a web browser again
– go to configuration and scroll down and

See if the Modem connected. If yes you are done. If no continue.

– go to expert
– go to SSH-Access
– log on (user pi-star + your password)
– type “sudo service mmdvmhost start” press enter
– type “exit” press enter
– done
– If Modem still does not connect then
– open your pi-star dashboard in a web browser
– click on Admin
– go to configuration and at the bottom click on configure wifi and if the ssid shown is correct click on save(and connect) and exit.

The modem should connect and the IP address should show on the screen and the status should show interface is up in green.

You have completed the upgrade.

ZUMspot board connected to GPIO:
sudo pistar-zumspotflash rpi

MMDVM_HS_Hat board with 14.7456 MHz TCXO connected to GPIO:
sudo pistar-mmdvmhshatflash hs_hat

MMDVM_HS_Hat board with 12.288 MHz TCXO connected to GPIO:
sudo pistar-mmdvmhshatflash hs_hat-12mhz

MMDVM_HS_DUAL_Hat board with 14.7456 TCXO connected to GPIO:
sudo pistar-mmdvmhshatflash hs_dual_hat

MMDVM_HS_DUAL_Hat board with 12.288 TCXO connected to GPIO:
sudo pistar-mmdvmhshatflash hs_dual_hat-12mhz

Nano Hat board connected to GPIO:
sudo pistar-vyehsflash nano_hs

HS_DUAL_HAT (VR2VYE) connected to GPIO:
pistar-vyehsflash hs_dual_hat

NanoDV NPi board:
sudo pistar-nanodvflash pi

NanoDV USB board:
sudo pistar-nanodvflash usb

BD7KLE/BG3MDO devices:
sudo pistar-mdoflash

ZUMspot duplex board connected to GPIO:
sudo pistar-zumspotflash rpi_duplex

ZUMspot USB key:
sudo pistar-zumspotflash usb

USB-connected Libre Modem:
sudo pistar-zumspotflash libre

DMR: Adjusting the offset by Al AF4FA

Most of the boards lately have required adjusting the offset to function properly on DMR. Many boards are shipped with a sticker on the bottom with the required offset.

These are usually pretty close. There is however a way to get this more exact and specific to your radio. Luckily there is a utility built in to Pi Star that enables you to tune your offset.

All it requires is pen and paper, a calculator and a little time.

Step one is to gain ssh access to your Pi. The easiest way to do this is go to “Configuration” then click “Expert” then “SSH Access” and log in with pistar and your password.

First, set your radio to 433.000mHz Talk Group 1 and Color Code 1 TS 1.

Next, use the command in SSH to start mmdvmcal “sudo pistar-mmdvmcal” then press “b” to start the BER tuning program.

1.Press the PTT on your radio for about 1 second. Then unkey.
2.If no BER response or a high response press the “F” key to raise the frequency and repeat step 1 until you get the smallest BER you can.

If you get to more than 1.5kc from the starting frequency without seeing a BER response or if the BER keeps increasing press “Q” and start the program over and press “f” instead of “F” and repeat steps 1 and 2 lowering the frequency until you get the smallest BER you can achieve.

At this point you can change the frequency step to a lower increment by using the “Z’ key and entering a lower step (50 or 25 or 10) and go back to step 1 to see how much lower you can get by using the “F” and/or “f” keys.

When you are satisfied with the BER then do the following.

However far off you are from the starting frequency of 433mHz is what your RXOffset should be set to plus or minus.