Category: Digital modes

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Large screens, digital modes, and beefy processors

A couple of constructors have been busy pushing the limits …

Digital modes µBITx in a box

Felice IK1ZVJ  project stems from his passion for digital modes. He says “The union between µbitx and raspberry works well”.   Felice combines a µBITx with  a raspberry pi and a large pop-out screen in a single portable package for use with digital modes such as FT8.

The LCD screen is mounted on an old CD mechanism to provide automatic ejection from the enclosure.

The project includes a dual power supply with a built-in power supply and battery power for portable use.  He foresees his pr  ubitx, only being used with the raspberry pi on digital modes. The raspberry pi is loaded with WSTJ-x for use on the FT8 and FT4 modes, and for FL-DIGI for PSK and RTTY.  His enclosure uses a 3U rack  (9 cmx40cmx43cm).

You can see more on his video:  https://youtu.be/TlndGOyNtVc  or you can contact Felice via email.

Ashhar Farhan is pushing the boundaries

Ashhar Farhan VU2ESE, designer of the µBITx previewed a Raspberry Pi board for HF radios with a high end codec at the FDIM (prior to Dayton Hamfest 2019).

This is for a new radio that he is building to push the limits of what his homelab capability can produce.

The story so far is that there is a very low noise 24 bit codec on a custom board that plugs into the raspberry pi. The display is a 7 inch capacitive touch screen device.

The radio is a single conversion, very low distortion superhet without any amplification before the crystal filter and triple tuned filters for each band.

Ashhar says “Nothing is casual about this radio. Even the power supply had to be included to have low noise rating.”

Reference

 

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Using a USB hub for a single USB cable to your PC

Nigel G4ZAL has tweaked his ubitx so that he has an ‘all in one’ rig for FT8 and other digimodes, including CAT control (FT-817 emulation).

To achieve this, he added an un-powered 4 port USB hub inside the rig and used a cheap USB sound card (discarded casing shown to right side of the pics below).  He cut the USB cable and hard wired the USB hub from the back panel and into the Raduino via the USB hub.   He didn’t connect the USB 5v power into the Raduino).   He also hacked the USB sound card so he could wire it directly to the corresponding MIC and SPKR wiring (used an old PC CD-ROM audio cable).

He is using the latest firmware KD8CEC in the ubitx and now has CAT control and sound  over a single USB cable to his PC/laptop.

Using the hub, he can also upload new firmware without opening the case.

In response to a question as to whether isolating transformers are required, Nigel noted that he had built a couple of devices like this and never had any issues requiring isolation transformers (He has some, but he never fitted them as the mod worked fine as is).


He used a USB cable “Mini USB 5pin male to female with screw panel mount extension cable” from eBay.   Nigel’s was wired incorrectly as the colours did not match the USB standard.  He had to wire according to how the manufacturer had made it.  He cut the cable to suit and hard wired it to the USB hub removing the original connection.

The USB hub was made by Startech, but any hub that can fit inside your enclosure should work.  Nigel removed 2 of the USB sockets on the hub and hard wired the stripped down USB sound card.   He removed the USB connector and 3.5mm audio/mic sockets and soldered these connections direct to the hub.   He also added connector pins for the audio/mic (CD-ROM) cable.  He went to these extremes so that the hub and sound card would all fit inside his enclosure.  If your enclosure is larger they can all be simply plugged together.

The USB sound card can be found on the famous auction web site. Nigel’s was an “External Virtual USB 3D Sound Audio Card Adaptor Converter Mic/Speaker PC Laptop“.   Nigel hard wired the Raduino USB side of the connector to the hub as well, but he didn’t connect the 5v power line (the Raduino is powered as normal).

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Is a heatsink required on FT8 mode?

One of the challenges with digital modes is their higher duty cycle than phone or CW.   However, Ashhar Farhan VU2ESE, designer of the µBITx, assures us that on FT8 the standard heatsinks supplied with the kit are adequate.  FT8 has a 50% duty cycle.

This may not apply with other digital modes such as WSPR.

Reference
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Connecting your rig to a computer

Connecting your µBITx can be done in a number of ways.   Some people will want to guarantee that their computer is fully isolated from their rig and will make or buy interfaces (Signalink, EasyDigi, etc.).  Others are quite happy to wire up a cable for USB control and another for the audio in/out.    In reality, transformers and other forms of isolation don’t necessarily always work.  RF can get into cables or the computer directly or indirectly.

Gordon KX4Z provides some useful links for reading up on rig/computer connections:

Wiring

http://qsl.net/kx4z/DigitalConnections.pdf

http://arrl-nfl.org/wp-content/uploads/2014/02/Digital-Connections.pdf

Cheaper alternatives to signalink

http://www.qsl.net/kx4z/TNCConstruction.pdf

With relay:

http://arrl-nfl.org/wp-content/uploads/2014/02/TNCPDB-Construction-Manual.pdf

Dealing with RFI

http://arrl-nfl.org/wp-content/uploads/2014/02/RFIFIXES.pdf

Reference
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RTL-SDR is mated to uBITx

Ian KD8CEC is working on a new release of his CEC firmware for the uBITx that will be more modular in approach (picking up on John VK2ETA’s mods to Ian’s firmware), interface with a range of displays (I2C versions of the 1602 and 2004 displays as well as the display that comes with the Raduino).  More importantly, however, this new version will enable the µBITx front-end of the receiver to be connected to an RTL-SDR USB device.  The RTL-SDR device will draw on the  HF receive sensitivity of the µBITx  along with the front end bandpass filter and first IF roofing filter and associated IF stage amplifier (normally at 12MHz) to produce a quality SDR receiver (for just a few $s invested in the RTL-SDR tuner).

This version is available to download (1.071 Beta) from Ian’s website now.

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An FT8 black beauty

Bill KC5SB has been using his “black beauty” µBITx on the FT8 digital mode and has already worked a station in Brazil with no problems.  Bill has installed a fan because he spends a lot of time on digital modes. The display has been replaced with one with a blue background (goes better with black) and the unlabelled switch on the back is for the fan – high, off, low.

The case can be purchased here.  It has, of course, been painted.

Reference
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WSJT-x release addresses Linux issues with uBITx

JP Bhatnagar, VU2SPF, has advised the list that the anticipated announcement  of a new version of WSTJ-X has been  made by Joe Taylor of the WSTJ-X development team. This mentions addressing ubitx transceiver connectivity with WSTJ-X.   WSTJ-X  has become very popular with amateur operators, as it implements the exciting new FT8 digital mode.
The full announcement follows:

The WSJT Development Group is pleased to announce a third Release Candidate of WSJT-X Version 1.9.0.  A second release candidate, v1.9.0-rc2, has been tested in the field over the past three weeks, including a public test of FT8 DXpedition Mode conducted on March 6-7.

A General Availability (GA) release of v1.9.0 will be announced at a suitable time, probably in the near future.  After that time you should stop using any -rc# release candidate.

Here’s a short list of features and capabilities added to WSJT-X since Version 1.9.0-rc2:

1. Corrected a number of flaws in Fox behavior, FT8 DXpedition Mode

2. Allow Hounds to use compound callsigns in FT8 DXpedition Mode

3. Write debugging information to FoxQSO.txt

4. Fix the “Blue Decode Button” bug

5. Allow partial processing of incoming UDP Reply messages so that non-CQ/QRZ decodes can be processed. The processing is the same as double-clicking the same decoded message within WSJT-X except that “Enable Tx” will not be enabled.

6. Send DX grid locator to wsjt_status.txt, for use by applications like PstRotatorAZ

7. Correct the display of DXCC status of KG4 calls

8. Updated copy of cty.dat

9. Updates to documentation

10. Updated Hamlib functionality including changes to the Yaesu FT-817  back end that allows the uBITx kit transceiver to be CAT controlled by WSJT-X.

10. Other minor bug fixes

Reference
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WSJT-X, KD8CEC code, and Hamlib

Rod KM6SN found that WSJT-X running on some versions of Linux would not work well with the µBITX. The problem was the Hamlib FT-817 protocol was not successfully connecting to the uBITX at startup.

For the past two weeks Rod has been working with Bill Somerville, G4WJS (developer of Hamlib) on the issues.   He explained the nature of the problem, and provided CAT link protocol logic analyzer traces, and did bench testing of new Hamlib code Bill provided.

Bill took a lot of time out of his schedule to work on this, and it has borne fruit, having now identified the area that needed changes, provided modified software, and stayed with the problem through quite a few iterations of testing.

Rod and the rest of the digital mode enthusiast community will  no doubt be grateful for Bill’s persistence.

The Hamlib FT-817 protocol has been modified to resolve the problem, and there should be an official WSJT-X release for Linux including this patch soon.

Details will be posted on uBITx.net when the new WSJT-X version is available.

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