Digital Modem from BG5ROJ… R.I.P.

Hi ! I received a lot of questions related to this modem, but I would like to inform all of you of 2 things.

First, when I bought my Elecraft KX2 back in May 2016 at Dayton, I stopped using the modem and start using the Elecraft internal decoder for CW, PSK and RTTY. I also combined the use of the KX2 with the K-Board from QRP Works, that is indeed giving me a lot of fun and satisfaction.

Second, earlier this year, I was looking to use again the BG5ROJ modem, but, not so lucky I was, the modem died, I have never found why, and it never turned on again since that time.

To be honest, I do not have the skill to repair the modem, neither planning to buy another one. I’m still having my NUE-PSK as a spare digital modem, but did not use it either.

So, probably I will not be able to answer more technical question about the BG5ROJ modem. You will understand, as time go by, memory do so.

I really hope all people who having this modem or planing to buy one will have great time with it.

Meanwhile, do not forget to follow me on Twitter @VA2SS, and subscribe to my blog and my YouTube channel as well.

Have fun and stay tuned!

de Jeff | VA2SS


Digital Modem from BG5ROJ: New firmware 1.04b available


HardwareChipA new firmware is now available for the Digital Modem from the BG5ROJ group : version 1.04b.

You can download the firmware upgrade at this link : Firmware 1.04b download link

Thanks to Berj KI3U for the hint!

Note that you must also have the PC software running on Windows platform to proceed with the upgrade. The software can be found at the link : PC upgrade software


For more information on how to upgrade the modem, please check you user manual. It is really important to follow carefully the manual instructions to make sure to not bricked your modem. A useful hint, make sure to use fresh batteries for this step.

How to upload the firmware?

The modem has a firmware uploading feature to enable more future functions and features. Follow the steps below to start the firmware uploading:

Step 1 : Rotate the VOL potentiometer to the right end, turn the unit on and it will enter the boot-loader mode.


Step 2 : Connect the USB cable between the PC and modem, load the dsPIC33E/PIC24E loader Application program, enable the USB upload feature and then click “Connect”


Step 3 : Load the new firmware, click “Erase-Program-Verify”, as the picture below:

Meanwhile, do not forget to follow me on Twitter @VA2SS, and subscribe to my blog and my YouTube channel as well.

Have fun and stay tuned!

Jeff | VA2SS


ADSP Audio Filter FDS-02 from BG5ROJ

Hi guys,

I just received yesterday from my friendly group of ELEKITSORPARTS, a small and smart group of amateur radio components designer and builder, the ADSP Filter FDS-02. They sent to me, for testing and review purpose, this small and effective audio filter that do more than just filtering!


Meanwhile, you can visit their website at

Do not forget to subscribe to my blog and my YouTube channel as well.

Have a great summer and stay tuned!


Jeff | VA2SS


Digital Modem from BG5ROJ: UPDATE on the SDR transceiver add-on board

Hi everybody!

I received a good news from the BG5ROJ group earlier today.

The transceiver add-on board is still in progress, as well as the firmware needed to use all the new functionalities that the add-on board will bring with the modem.

Here a few words I received from the builder:

Now the hardware is ready, but the firmware for the modem to support this module is in programming. I think it will take at least 1 month.

from Elekitsorparts team

sans-titreSo, we all really hope that we will be able to try this new add-on board really soon. At least, I will be able to keep all of you well informed as soon as I receive mine for “Beta” testing purpose. I will, of course, do a full review on my blog with as much details as I can.

A few more words from the builder’s group that is keeping me very enthousiastic:

You will be informed when the TRX module is ready. We will send a unit to you for review.

from Elekitsorparts team

If you would like follow more easily my adventure, do not forget to subscribe to my blog and my YouTube channel. 🙂

Stay tuned guys…. more to come!!!


Jeff | VA2SS

Digital Modem from BG5ROJ: New firmware with CAT support for the FT-8×7 soon!

Received additional information today originating from the «Ham operators group from China – BG5ROJ» on new firmware to be released soon for their digital modem

As a beta tester for this group of ‘geniuses’, I will, as a beta tester, be able to put this new firmware update through its paces

The new firmware is in development at the moment, and it will support the FT8x7 CAT function.

More information will follow as soon as all the tests are completed.

Stay tuned everyone!


Jeff | VA2SS


Digital Modem from BG5ROJ: A new SDR transceiver add-on board soon!

I received direct information today from the «Ham operators group from China BG5ROJ» about a new product that will be release soon.


As a beta tester for this group of genius guys, I will personally be able to try a new add-on board that will add a «complete» SDR transceiver functionality inside the Digital Modem! This will let the modem to be a complete QRP transceiver solution by itself.

As you probably seen in my previous videos and posts, an antenna port will be easily added within the removed cap on the right side of the modem. The add-on board will be connected inside the digital modem within the 2 onboard connectors already found on the modem board. So, the digital modem was already initially designed to host many other futur features by their designers.

The transceiver will have these specification:

Frequency range: 5MHZ ~ 50MHZ (No 80m and 160m band)
Working Modes: CW, USB/LSB, FM
RF Power Output: around 1W
Freq Stability: 7 ppm (Si570 Grade C)
Receive Current: 250 ma
Transmit Current: 1.5A
SDR Architecture: Quadrature Sampling Decoder (QSD)
Sensitivity*:  MDS = -130 dBm
Mic Type: Internal MIC
Size (W x H x D): 59.6 x 85 x 10mm 

Here is the TRX add-on board that will give the full SDR capability to the digital modem.


Here is now the add-on board installed inside the digital modem… very neat installation!



The SDR transceiver display when the SDR function will be turned on in the menu. Actual display is on 20m band.


A look at a tight integration of the standard transceiver functions on the small display: S Meter, mode display, VFO, etc.


So, this little nice Digital Modem will soon be a complete SDR QRP transceiver. They did not told me what will be the retail price or even when it will be available to order. But, compared to the price of the Digital Modem itself, it will not be too expensive.

For sure, I will receive a unit to test first as a beta tester for the group. So you will able to see on my Youtube channel how it works.

Stay tuned guys, more information soon!

Please, do not forget to subscribe to my blog. You will be informed as soon as I post new documents! If you have questions related to my blog, feel free to ask me questions!:-)


Jeff | VA2SS

Digital Modem from BG5ROJ: Record and playback a session

I tried a cool feature with the modem recently called “Voice Recording Function”. To be honest, I’m not totally agree with the use of the word “voice”, because when playing the recorded file, you did not hear anything. My guess it is related to the translation from chinese to english. Hi! 🙂

But what this feature really do? When pressing CTRL-V on the keyboard, it will start recording on the micro SD memory card, all the signals received inside the signal window that has been displayed on the digital modem at that specific time. It will cover mainly ± 2.5 kHz of bandwith. The file stored on the memory file will have an extension .VOI. That type of file is associated with an old file format from the company Voyetra well known is the music gears world. But don’t be fool, I enver found a way to play all theses files created with the digital modem directly from your PC by using a software on Windows. All files will be located on the micro SD card inside a directory called : “REC”.


OK, but until now, how this feature could be cool??? Let me show why this sounds cool!! After you saved a few records, if you go into the MENU system, you will find an option called “Replay Voice REC”. By selecting this option, you will then see all recorded files you previously did with the modem.

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You can also manage your saved files directly from the digital modem by selecting a file that you would like to delete by pressing the DEL key on your keyboard.

Here is a short video that demonstrate how to use this cool feature.

I really hope you liked it!

Please, do not forget to subscribe to my blog. You will be informed as soon as I post new documents! If you have questions related to my blog, feel free to ask me questions!:-)


Jeff | VA2SS

Digital Modem from BG5ROJ: A few decoding examples

Hi guys,

Here a few short decoding sessions that I made on 20m using PSK31 and CW protocol.

I really hope you liked it!

Please, do not forget to subscribe to my blog. You will be informed as soon as I post new documents! If you have questions related to my blog, feel free to ask me questions! 🙂


Jeff | VA2SS


Digital Modem from BG5ROJ: Part 3 External and internal view

Hi everyone,

Today I will show you in small video the external and internal view of the Digital Modem from BG5ROJ. The video consist in a small “guided tour” of all connectors and features we can find on the unit.

I will come back later this week with more videos and more explanations on the operational side of the modem: the decoding part, PSK, RTTY, etc. There also plenty of other features that will be also explained later, like the I/Q input using an Elecraft KX3, the audio recorder and playback feature, etc.

I really hope you enjoy this video.

Don’t forget to subscribe to my blog. You will be informed as soon as I post new articles.


Jeff | VA2SS


Digital Modem from BG5ROJ: Part 1

After a few weeks waiting for my new toy, it finally arrived today! The new Digital Modem from BG5ROJ. A brand new product from a Chinese amateur radio. I bought the modem directly from their website :

Let me tell you that at 165.99$ USD plus shipping, it is a real bargain! The overall quality is also amazing!


I will do many tests in the next days,

so I will my post my review in many parts.


First view: The hardware

Actual specification

  • Supported Modes: PSK, RTTY, CW (new modes may be added by updating the firmware)
  • Input and Output Ports: USB-HOST, Mini-Din6, 3.5mm Stereo
  • Display: 3.5″ 128×64 LCD
  • Power Supply: 2 AA-Size Battery or single cell Lithium battery
  • Power Consumption: Less than 0.5W
  • Size: 160 x 65 x 27 mm

B1 is a push button to select et invoke menu items. B2 is also a push button but also a scrolling wheel to select options. To turn ON the unit, the user must push B1 and B2 forward for 2 seconds. It is essential if the user do not want his unit turned ON by accident when stored with all other gears when travelling.


The unit is very nice build. The screen is really sharp and clear, very easy to read as you can see. The unit is approximately 5 in. X 2.5 in. X 1 in. A very small form factor for all of us who expect to carry their gears in with less space.


The modem hopefully is very easy to integrate with the transceiver, especially with the Yaesu FT-817. It uses the standard DATA pinout found on the transceiver. The DATA cable is provided with the modem at no extra cost. The USB connector is used to connect the keyboard….. hopefully a USB keyboard !!! Very easy to find…. even the smaller one!!! The USB connector is also used for futur firmware upgrades. At the moment, I using firmware version 1.03. The manufacturer already told me that new firmware with other new functions will be available later…. so what about a piece of hardware that will host new feature! What a joy!

The modem supports a direct IQ signal input from a SDR receiver. To activate it, you need to change the signal source configuration in the main menu. The demodulated audio is sent to the phone jack, and the demodulated text data is showed on the LCD.


There is also a PHONE and AUX conenctors. This 3.5mm phone jack is used to monitor the receiving audio from your external transceiver, or to monitor the
transmitting audio tone (modulated tone) from the modem itself. Depending on the different input signal source configured in
the main menu, this 3.5mm phone jack plays different monitoring tasks:

A. External Data: <In Receive> It monitors the received audio tone from your transceiver <In Transmit> It’s muted.
B. Internal MIC: <In Receive> It’s muted. <In Transmit> It monitors the transmitted audio (modulated) tone from the modem itself.
C. External I/Q : <In Receive> It monitors the decoded I/Q audio signal tone from your transceiver. <In Transmit> It’s muted.
D. Internal TRX Mod: <In Receive> It monitors the decoded I/Q audio signal tone from the TRX module. <In Transmit> It’s muted.

The AUX connector is for a CW key. You can use a CW key instead of a standard USB keyboard for sending commands or characters. Let’s say you answer a CQ sent in PSK31, but by using your CW key. The modem will translate your CW in PSK31 as well as in other mode too….. like the Elecraft KX3 and K3 already do. It is easy to connect to the modem to other transceivers even if they do not have a DATA out capability.

20160418_203644145_iOS Their a small speaker to hear the BEEP command confirmation. The DC input (8V-26V) is for charging Lithium internal batteries when used. The user can choose between using 2 AA Lithium batteries, standard 2 AA batteries. 8 hours of operation is at the moment expected by using 2 fresh AA Alkaline batteries.

The built-in charging circuitry in intended for Lithium battery only, not for AA batteries. The unit will automatic detect the inserted battery category, and it will not charge the AA batteries. The lithium battery is not supplied in the package due to the air shipment regulations, you may need to locate one by yourself. However, a USB-DC cable is supplied in the package, and you may need a cell phone charger with USB port to charge the internal lithium battery at the same time.

If a lithium battery is used, you do not need the AA batteries, and you do not need to replace it after the power is used up. Instead, you need to re-charge it by connecting a USB-DC cable (also provided at no extra cost) with one end to your cell phone charger adapter and the other end to the DC IN port of the modem. The AA batteries are really convenient to locate. However, the unit will not charge it up even if you connect the USB-DC cable in. Do not forget to take the AA batteries OUT if you put this digital modem aside for long.

Take a look on the upper right part of the picture, there is also a small micro SD memory card slot. It lets you save your configuration settings, or even all the QSO’s you will do with the modem when operating.

A very nice addition!


A 128 MB micro SD card is also supplied with the modem at no extra charge.


An internal Lithium batteries is for clock time and date when the unit is turned off.

A plenty of menu functions is also available. This will let the user to choose between different protocols (BPSK, RTTY, etc.), and many other functions and features to customize the modem.

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OK that’s it for now! I will post more review in my next post.

Stay tuned everybody!


Jeff | VA2SS