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.


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:


Cheaper alternatives to signalink

With relay:

Dealing with RFI


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.

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.


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


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 when the new WSJT-X version is available.