OpenGD77 Recent Updates: W1RHS Edition 09/20/2021

Back in May 2019, Rick W1RHS shared an excellent presentation on BlueDV for Digital Ham Radio and he has continued to tinker with some of the latest digital voice related technology available today to the modern radio amateur.

You can learn more about this and many other topics by listening every Tuesday at 8:00 PM Eastern US time on Brandmeister talk group 31368 (STEM) via the North Star Digital Net led by Jim WA2UMP.

In the past, HVDN has covered the fantastic work that Roger Clark VK3KYY going all the way back to 2018 that he and others have done with OpenGD77.   

This open source alternate radio firmware and computer programming software (CPS) have a cult following since both expand on features not offered by the manufacture and at the same time, makes things even easier to use.

One common complaint about any DMR radio is that they are hard to program and as folks like Brian W2BRM have learned since winning a already programmed DM-1801 from HVDN as part of the LIMARC virtual hamfest,  OpenGD77 opens many doors to learn more about what can be done thanks to open source software and just a little more easily too than original user interface and software.

Latest Open GD77 Updates

For a really quick overview of OpenGD77,  you can load this alternate firmware on the Radioddity GD77 and also the Baofeng DM-1801, RD-5R plus some of the other variants that exist out there. 

Features like converting your radio into a hotspot with just the USB cable plugged into a computer or Raspberry Pi are just one innovation which makes the work of the OpenGD77 team really amazing.

Now, thanks to Rick W1RHS, he has packaged up a nice overview of non-DMR features that are now part of OpenGD77 and no other radio offers anything close to this, so keep reading

OpenGD77 Spectrum Scope Function

If you own an Icom IC-705, IC-7300, IC-9700, Yaesu FT-991 or any SDR devices, a spectrum scope is common place, but many hand held radios that offer this function like the FT-3DR poorly implement it. Even on such a tiny screen such as the GD77 or DM-1801, this is much more user friendly to help find VHF/UHF activity.  Here is how the new feature works with OpenGD77:

OpenGD77 Satellite Tracking Capability

Even the Kenwood TH-D74 or TH-D72 do not offer anything like this which are considered some of the favorite handheld radios to use with satellite activity since they both offer APRS capability, the out of production D72 being full duplex and the D74 having a built in audio recorder and SSB reception.

Now with your OpenGD77 enabled radio, you can use its internal processor to show the next satellite pass time and direction based on your location, which is actually really cool. Here are some details:

 

START>>>>> REALLY COOL FEATURE ALERT!!

END<<<<< REALLY COOL FEATURE ALERT!!

CPS Integration

Rick further shares that the CPS has an extra feature added to download the Kep's data and upload this to the radio, as well as setting the date / time of the radio. 

In the Extras -> OpenGD77 support screen of the CPS. Connect the USB cable to the radio, make sure the radio is turned on, and press the "Install satellite Keps" button. The CPS defaults to downloading the Keps from a specific web URL, however if the operator prefers to use a different source of Kep's data, they can change the URL.

The new satellite feature requires an accurate time-of-day clock. The radios do not have a hardware clock. OpenGD77 keeps the time and date in software. Because the time and date would be lost upon power down, a new feature has been added. Suspend Mode allows the radio to sleep in low power when the power switch is turned off instead of completely powering down.

Getting Started with OpenGD77

So, even if you have grown tired of DMR and are looking for other uses for one of your radios or to further enhance how you enjoy other aspects of the hobby with your DMR radio, here is how to get started with this great inexpensive radio along with open source software

OpenGD77 Main Web Site 

http://opengd77.com/

User Guide (View Online)

 https://github.com/LibreDMR/OpenGD77_UserGuide/blob/master/OpenGD77_User_Guide.md

User Guide (PDF Download)

https://github.com/LibreDMR/OpenGD77_UserGuide/raw/master/OpenGD77_User_Guide.pdf

Supplementary Notes

In May of 2021 the project needed to experience a reformatting for compliance with the General Public License (GPL). This set the project back a little, but is now again leading innovation in amateur radio today

• There is a different CPS. This is required. You need the most recent CPS for compatibility with the most recent firmware and feature updates.

Download the New CPS (required) Use the latest available version in that folder. 

https://www.opengd77.com/downloads/CPS/ 

• The firmware no longer contains parts of the official firmware. The old procedure had you load the firmware as an SGL file. The new firmware does not contain a copy of Radioddity's AMBE codec so it is no longer necessary tp encrypt the firmware into an SGL file. The new firmware is just a plain binary file (.bin). DMR requires the AMBE codec. 

The new CPS now extracts the AMBE codec from the official firmware before uploading to the radio. The new process requires you to first download and unzip the latest version of the official firmware (version 4.3.6) and extract the official firmware file. The instructions for this are described here: 

OpenGD77 Firmware Installation Instructions 

https://www.opengd77.com/static/firmware_installation.php#null 

• For legal reasons the license and readme text documents are required to be distributed with the firmware file. So the firmware file is now zipped into a package containing these other files

 Download  FW ZIP https://www.opengd77.com/downloads/releases/R2021052901/firmware/ 

• The Voice prompts have changed in this version

Download the Voice Prompts

 https://www.opengd77.com/downloads/releases/R2021052901/voice_prompts/

• The source code and build tools are available here if you are interested.

Download the Source Code 

https://www.opengd77.com/downloads/releases/R2021052901/sources_and_tools/ 

Legal Substantial portions of the source code have been written since the last public release. 

The only code remaining is copyright a small group of people including Kai DG4KLU, Roger VK3KYY, Daniel F1RMB, Alex DL4LEX and Colin G4EML. 

Code by minor contributors has been rewritten to overcome copyright and GPL License problems. 

The Hotspot code has been rewritten, and the code from mbelib has also been rewritten, to overcome GPL and license conflicts. All major contributors have agreed to the license change to BSD 3 Clause + non commercial

GD77: The first HT based Pi-Star hot spot

As mentioned here in the past, Roger Clarke is the wizard down under. He is known for his Git repository making the firmware upgrade procedure on MMDVM boards pretty painless and also his work surrounding an open source CPS for the GD-77 DMR radio.

For much of the summer, he has been working with Kai on turning the Radioddity GD-77 into a hot spot which is probably the most exciting thing I have come across recently.  This is such an amazing case of open source software at work and making closed hardware, much more open.

Head on over for a read on Roger's blog for much greater detail and get ready for some fun. My biggest questions are:

• Will this work with the Baofeng DM-1801 and other ODM variant radios?

• How will this impact the "hotspot" market and prices?

• Will other radios see similar innovation (Alinco MD-5TGP, Anytone 878, etc)

Continued Reading:

• GD-77 Hot Spot Mode

• GD-77 Community CPS

• GD-77 Frequency Expansion

• GD-77 Introduction to new CPS

• Improving the TCXO for Duplex Hotspots

Community version CPS for GD-77

I may start thinking of Roger Clark as the "Wizard of Melbourne" because of all his work lately with improvement considerations for the Radioddity GD-77.

Plainly put, there are a few areas that make this a "love it or hate it" sort of radio such as:

• Battery capacity should be better (7.4V at 2200 mAh stock battery)
• Lack of additional battery options (ability to purchase or extended life batteries)
• Computer Programming Software quirks and issues
• Certain radio functions like scan and monitor are flaky 
• RF wise, the VHF side of the radio is not as good as the UHF side
• Lack of memory for contacts
• Limitations around RX groups and zone
• More....

For a $80 to $110 radio depending on where and when purchased, its actually a much better radio than it may appear. 

The GD-77 does use the same charging cradle as the popular TYT MD-380 and speaker mic connections. A standard SMA antenna as found on radios like a Kenwood TH-D74, Yaesu VX-8, Icom ID-51, etc further allows for some interchangeability among accessories.

Community Version CPS

An issue with most all amateur radios was a lack of standardized programming software. It was common to need one or more software applications to program each radio.  The C.H.I.R.P  application changed that, but is not currently supporting any DMR radios or any digital voice radios for that matter. 

A lot of the CPS for various DMR radios are not full function, or at least how we want them to be.

Roger's thought of making this vendor CPS an open project is a really great idea.  Looking forward to where this goes! 

Related Links:

• Re-engineered Radioddity GD-77 CPS
• Roger's Github repository 
• Current replacement EXE as of 2/21/18 (In case it disappears)
• Current CLONE of Git as of 2/21/18 (In case it disappears)

Radioddity GD-77: Frequency Expansion

Roger Clark posted some great background and tutorial about modifying the executable file for the GD-77 programming software to expand the frequency range of his radio.

I decided to give this a try and have to say I have some mixed feedback, especially after reading a new FAQ found on the Radioddity website that got me excited...

(Radioddity GD-77 modified with 220 MHz experiment)

While Roger wanted to use the GD-77 on the Australian UHF CB band for "testing", my goal was twofold:

• Be able to program "listen only" capability for the New York Police Department (NYPD) and New York Fire Department (NYFD) which operate in 470-490 MHz range still using analog FM. This worked great!

• Experiment with adding 1.25m capability and see how tolerant the front end filtering is within the GD-77 on  both transmit and receive performance.  Worked not so great...

Expanding UHF receive capability

Before talking about the GD-77, the popular TYT MD-380 has a major limitation for users in the New York Metro area in that it can only receive up to 470 MHz out of the box.  Many users have easily modified a file to permit wider band receive performance to facilitate NYPD and NYFD monitoring. International users have done the same thing for UHF CB band allocations. Here is how to do this on a MD-380G and would also work the same way for the non G version for both UHF and VHF versions as well as the MD-390 series and all the rebadged versions of this radio including the  Retevis RT-3. 

MD-380 frequency expansion

Navigate to where your CPS software is installed and locate the "setting.ini" file.  Right click to open it as "edit"  and open it up using Notepad.

Modifying the area near "[FreqRange]" allows the software to select different versions of your radio and also the frequency range.  The example above shows how I expanded a UHF MD-380G to 400-520 operation. I also deleted out the other radio model options so that I always default to the radio I use and never get the "invalid" model issue. That step is optional if you have VHF and UHF models, you do not want to do that.

Save the file and boot up the software and you should see it worked.  Make your code plug and write to your radio and it should be expanded now. 

You can also "shrink" the range if you do not wish to do anything outside the ham bands as well. 

Once you do this, you can not go out of band on the radio unless you change the "setting.ini" file again.

Doing the same sort of thing on the GD-77

Its a little more complicated on the GD-77 compared to the MD-380.  Roger has good instructions and a file ready made you can use to implement the modification.  To do what Roger did, you need to know how to recompile executable files, so it may not be for basic computer users. Couple issues I found when using his modified file:

• My GD-77 gave me an error when I tried to use the 130-174 or 130-520 setting in either Frequency A or B. I had to change it to 136-500 for it to work in both ranges. 

• The filtering in the GD-77 is finely tuned as expected.  I was able to get it to work between 136-174, not the 130-180 that the manufacturer states as found on the FAQ page mentioned earlier. Same with 195-285 being more like 200-260 and 390-520 being closer to 395-500. The 200-260 range was what I was interested in fell even shorter of expectations.

• US 1.25m "220" ham band performance is underwhelming on the GD-77, but would work just fine for low power operation for use with your own hot spot if it has 220 MHz capability. instead of using 70cm or 2m. I measured 223.5 MHz transmit power at 210mW when on the high power setting and 29mW on low power setting using analog FM mode. 

• After additional testing, I found 2m and 70cm operation to not be as it once was. I put the radio back to normal to avoid long term damage to the radio. 

Verdict

Nice experiment. I put my radio back to normal operation though pretty quick. Would like to see Radioddity introduce a tri-band version much like some of the inexpensive analog only Chinese mobile and handhelds that have become recently available . It be great to see DMR come to 1.25m in the US, especially since the Jumbo Spot and its legitimate ZUM Spot version seem 220 capable.  Future article about this to come in the near future.

Comparison of entry level DMR Radios (2017 Edition)

Many people say that they wont get interested in certain digital voice modes for the following reasons:

1. There needs to be repeaters in the area to use first.
2. There needs to be a dual band HT available.
3. There needs to be a lower price point to experiment with digital voice modes.

The good news is that item 2 and 3 on that list are a reality today. Item 1 is coming along in the area with details covered in an upcoming article about current area DMR and other digital voice mode repeaters.

This review is focused on entry level DMR radios with a goal to compare them along with some details I like and dislike between them.

This review covers the following radios pictured, left to right.

• Radiooddity GD-77 VHF/UHF
• TYT MD-2017 VHF
• TYT MD-380G (UHF)
• Tytera MD-380 (UHF)
• TYT MD-380G (VHF)
• TYT MD-380 (VHF)

I would like to cover Yaesu Fusion and Icom D-Star hand held radios, but there are currently no current radio available sold under $200, unless I include the brand new Yaesu FT-70DR which is priced at $199.99 at the time of this article at most resellers. Icom only has one HT, The ID-51A using its GFSK based D-Star mode and is priced at over $400. Kenwood offers the super fancy  TH-D74A which now does D-Star, but is almost $600 but also has the 220 MHz band.

I do want to mention that Alinco has reduced the price of its UHF DMR radio since last year by $70, the DR-MD40 is now $199.99, but for a mono band radio, I did not include that review at this time.

Here is a size comparison of some of the most popular radios today used by DMR enthusiasts that are considered "ham grade" and not commercial Vertex, Hytera, Motorola and others. I have also not included the USA designed, overseas manufactured Connect Systems (CSI) or Bridgecom radios that provide DMR as that is for another article at a later date.

Be warned, all radios in this review are "Made in China" but only the Radiooditty radio is not made by a 100% Chinese owned company to the best of my knowledge.

Country of origin should not matter in our global economy, but I do want to point out that at the price points listed in the chart below, the Chinese vendors are producing a very capable modern radio. This may help push European, North American and other Asian countries such as Japan put out a f-f-f-fantastic DMR product with this open standard digital voice mode in the future.