The All-band HF Amateur Radio Transceiver: Just waiting to be modified
Peter M0HYT likes to do it the hard way. He has designed a circuit board layout with the Nano on board and stocked with traditional through hole components. You will see his new board photographed alongside a uBITx kit main board from HF Signals. It looks pretty stunning!
Download the design details:
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The KD8CEC firmware provides a lot of customisation features through uBITx Manager software. Many user of Ian’s firmware are not aware of all the built-in features of his firmware. This is one such instance!
JJ1EPE raised a concern that his display in CW mode was “off frequency”. Well, it was from his perspective, but then the display was all the time showing the TX frequency not the offset frequency where the station he was listening to.
CW offsets create headaches in how you represent the frequency on a display. In SSB the frequency you see on the display is the frequency of the suppressed carrier on receive and the same on transmit. If you tune to the carrier frequency of a received station you won’t hear anything. To get a sidetone we have to tune off the transmit frequency by a few hundred hertz. Most people have worked out how to set the offset on the uBITx.
The standard that Ian KD8CEC has applied is to always show the TX frequency by default (except where RIT or SPLIT mode is selected).
However, if you want to change the approach, do the following in uBITX Manager:
– Enable Adjust CW Frequency
– Shift Display Frequency on CWL, CWU Mode
If you select this function, the LCD will show the frequency at which the radio is being transmitted (the offset you prefer is added or subtracted to the actual RX frequency reflecting the CW-L or CW-U mode selected). This may be just the thing you were looking for!
Some of you are waiting with baited breath for the JackAl Board, announced by Jack W8TEE. You can get yourself geared up for the JackAl by pre-purchasing some of the kit required, as it is due to be released shortly. You will need a colour touch display panel, a Teensy 3.6 processor and associated Teensy audio board.
There are two display options for the JackAl board: 5″ or 7″. Neither is likely to fit in your existing µBITx enclosure, so you may also want to purchase a new enclosure.
The panels can be purchased from BuyDisplay.com. Their order numbers are:
ER-TFTM050-3 (5″)
ER-TFTM070-5 (7″)
Both displays use the following options:
4-wire SPI interface
3.3V
Resistive touch
No font (the library is being used for fonts)
Both are 800×480 displays using the RA8875 chip. If you run the samples using a touch screen, make sure you run the Calibration sample program first.
The Teensy 3.6 and its associated audio board can be purchased from the manufacturer’s website or from other sources.
Rohn KR0HN was “parts shopping” online when he came across a microSD card extension cable.
This could be used to extend the microSD card slot of the Nextion display out to the exterior of the case. This would be handy for upgrades to the display firmware as new features become available for your display.
The link to the amazon page is: https://www.amazon.com/Extension-Extender-Flexible-Monoprice-Raspberry/dp/B072X27V58/ref=pd_sim_147_14
Ian KD8CEC has been looking at power consumption on the Nextion display and how to effectively dim the screen for portable µBITx work, where you want low current drain.
The following picture show’s Ian’s display (2.8″ TJC Chinese version) at Full Power:
And the screen fed with a series 50 ohm resistor (1/2 watt rated or more):
The slightly dimmer display halves the current consumption from 89mA to 44mA with a series 50 ohm resistor (made up of two 100 ohm resistors in parallel (or 3 x 150 ohm resistors in parallel). The Nextion screen has a built in software dimming function, and this can be adjusted in Ian’s Nextion display firmware. However, the feature generates noise in the µBITx and is not recommended.
Resistor installation
Installing a series resistor (with a value between 20 ohms and 100 ohms) in the +5V power lead will cause the display to be dimmed, but function normally (except for use of the micro-SD card reader). The resistor could be installed across a slide switch or toggle switch (with one pole shorted and the other going through the resistor) to allow for two settings (normal, dimmed). This could be handy for night time or portable use. The circuit diagram for this is as below:
For further details see Ian’s website.
Jon Titus KZ1G shows off his breadboard construction technique, which he uses while his rig is under development. The board is mounted on a piece of plywood and usea 1/8-inch clear plastic as front and rear panels for controls and connectors. This “breadboard” technique has been used by Jon for other projects, because it lets him rearrange control locations, ensure clearances between components, jacks, heatsinks, etc. In this way he doesn’t ruin a nice front panel when later adding an extra pushbutton or switch, etc.
After learning about the W0EB and N5IB RadI2Cino (Rad I2C ino) project he needed more room for the replacement board and a larger LCD. A section of plywood was glued on the front (see photo) and the front panel was then able to be moved forward by about 4 cm. Jon quickly added an extra pushbutton, and drilled holes to mount the LCD.
However, when do you make the call to put the whole thing in a proper metal case Jon?
Mike N6CMY has been doing some mods on his µBITx, including some of Allison’s mods by substituting 2n2222’s and a BFR106 for the 3904’s on the RF lineup (pre-driver and driver stages).
In terms of output power the results are impressive. But in terms of levelling up the output… well not so good.
Mike measured 12W on 10M and over 35W on 40M! He was a bit taken aback at this point!
He finally bit the bullet and used K9HZ’s multi relay/pot method for levelling the response.
Mike was reluctant to use such a brute-force solution for a subtle problem but he now measures 15W on 80, 40, 20 M and 12 on 10M. VICTORY!!
Arvo KD9XLC has put one of these 12v fans that cost less than a dollar on the back of his Excelway case from Bangood (which apparently now on sale for $8.88).
You could attach the fan to the cabinet with hot glue, or use the correctly sized bolts/nuts.
And if you don’t want those fans to run on receive connect them to the TX 12v line, namely at pin 3 on U2, which is what Arvo did.
Ian KD8CEC has given us another simple S-Meter Sensor for the uBITX using an LM358 Op Amp which is one of the cheapest IC’s you can purchase.
The circuit is pretty straight forward:
Full instructions can be found on Ian’s website at www.hamskey.com
Akira Horie JJ1EPE has had an article published about the µBITx in the 19 June edition of the CQ ham radio magazine of Japan.
The magazine is of course in Japanese. Akira’s article covers:
Gaining certification for a home-built rig is not straight forward in Japan and involves:
Akira has the all important certification and license to use his µBitx from the relevant Japanese government authority.
He is now enjoying QSOs on his µBitx!