The All-band HF Amateur Radio Transceiver: Just waiting to be modified
David N8DAH is now producing a very handy digital interface kit. This is a Gordon Gibby KX4Z design, and it features:
The kits are available for:
US$15 unassembled or US$20 assembled
https://shop.kit-projects.com/index.php?route=product/product&path=59&product_id=120
Rahul VU3WJM has designed a single sided PCB replacement for the Raduino in a form factor of 20X4 line LCD.
In fact, this board supports both a 2 line LCD display (1602) and a 4 line LCD display (2004). Rahul has also added a few more electrolytics, separated the Analog and Digital ground plain, and the Nano module is on the component side to make it easily plugable. He has assumed mostly through-hole components but SMD pads have also been included for coupling and decoupling caps.
All fabrication files are being made Open Source for personal and club use only. He asks that you verify the Gerbers before making the board! Rahul would also welcome your feedback on any further improvements that could be made to the design.
John Scherer came across an interesting, i2c addressable rotary encoder board that allows you to connect encoders in just about any configuration.
The board has pins for digital or ADC I/O, has 256 bytes of eeprom, pads for setting each encoders i2c address, and works from 3.3 – 5V DC. For something like the µBitx, this could be an easy way to add additional physical I/O (i.e. knobs).
There is also a video that gives a pretty good overview of how they work.
John VK2ETA suggests that on a read of the manual it appears the 256 registers are at one I2C address, and are divided between control registers and EEPROM addresses (two banks of 128 bytes).
The current implementation has the current modes for the encoder:
A. Relative, where the counter keeps the number of steps since last read. Reading it resets the counter to zero. Useful for frequency tuning in our case.
B. Absolute
B1. Without limits.
B2. With user defined limits
B2.1. No wrap around, like a potentiometer, hard stops at the limits.
B2.2 With wrap around, goes back to low limit if high limit is exceeded and vice-versa.
The encoder push button events are:
– button down
– button up
– double-press with user selectable double-press interval.
Current consumption is listed at less than 2mA plus LED current if used.
The board mounted PIC controller’s program is open source so it can be customized as well.
Tom, WB6B believes they keep a counter in the PIC chip that is on each board, so each time you check the status of an encoder board it will tell you how many encoder pulses took place since the last time you polled the data. This should greatly relax any timing issues.
David N8DAH from Kit-projects is marketing Gordon Gibby’s outboard relay mod as a kitset or for $5 more as a built-up board. This includes the circuit board, and all parts (including relays, diodes, inductors and caps).
Cost might seem high but David assures us he will be using quality parts.
The pre-orders were snapped up pretty quickly, but new stock will be coming shortly once the pre-orders have been shipped.
https://shop.kit-projects.com/index.php?route=product/product&path=59&product_id=119
PJRS, the makers of the Teensy family, have just added the Teensy 4.0 to their processor line up. Jack W8TEE says, “It is a beast!”. Perhaps he his contemplating an update to the JackAl board for the µBITx?
Brad N8YG has been reading over posts concerning the ssm2167 compression pre-amplifier with quite a bit of interest. So he finally integrated the board into his ubitx v5.
He put a trimmer on the output of the board, and potentiometers on the compression, and noise gates. The problem that he ran into was that on the air, rotating the 100K compression potentiometer had little to no effect. However he was getting compression that was clearly audible on the air.
He re-read the data sheet for the ssm2167 more thoroughly and found that the input voltage need to be quite low at -20 to -30 dBV. A quick check on the electret microphone output using the oscilloscope, showed a much higher output from his microphone.
This led to him adding another pot to trim the input voltage. He still needed the 5V to get to the electret so he wanted the trimmer after the 0.1 uF surface mount capacitor on the board.
Brad modded the board by removingthe 0.1 uf capacitor, and he made connections for the trimmer after the 0.1 uF capacitor.
The net result is a board with three additional potentiometers and one trimmer. The trimmer adjusts the output voltage, and potentiometers control the input voltage to the board, compression and noise gate.
On the air.. with the compression potentiometer turned down the rig sounds like it has no compression… while turning up the potentiometer makes a profound difference in on the air sound. The rig now has a LOT of punch and the power meter goes way up.
Brad believes that what was happening was that the input level was too high forcing the chip into the limiting portion of the transfer curve. Now that the chip is operating back in the linear portion, all is well!
Ashhar Farhan VU2ESE, the designer of the BITx range of kit transceivers marketed through HF Signals has launched his next design: the Antuino.
The website states that:
“Antuino is an accurate instrument that can be used in the field to measure SWR, field strength, modulation, etc. In the lab, it can be used to sweep filters, measure gain, distortion, frequency response, etc. It works upto 150 Mhz. On the third harmonic, it is usable on 435 Mhz band as well (with reduced sensitivity).
“The Antuino, unlike simpler instruments is based a superhet architecture that measures the response of the antenna or circuit at exactly the tuned frequency. It is based on Analog Devices’ Lograthmic Amplifier, the AD8307 to provide accuracy of 1db in your measurements. It is tuned with a crystal locked PLL based on Si5351 oscillator chip.”
Ian from Computer Freaks Anonymous found the uBITx.net website and let us know about his Nextion bezels.
He has been producing these on his CNC machine for some time now. They are manufactured from acrylic, have tapped holes to secure the display with plastic screws (supplied).
The bezel allows you to cut a rectangular hole, glue the bezel in place and secure using the screws. It provides a nice glossy finish and they can be produced in many colours. From the front view there are NO screw heads visible, adding a more professional finish to your project.
He ships worldwide, to US, Canada, UK, Austria, Germany, etc.
More info here:
https://www.compfranon.uk/product-category/products/screen-bezels/nextion/
Mark AJ6CU released a fan shroud for the “tall” Sunil case a short while back. See https://www.thingiverse.com/thing:3790450
He was curious to check out its effectiveness, against just using the supplied heat sinks or using the heat sinks with a fan. So here are the results….
Test Setup
Search for: ” DROK Car Voltage Temperature Display” on amazon if you want one!
Unfortunately Mark took the “shroud measurements” on a different day than the”no shroud measurements”. So focus on the temperature gain over “ambient temperature, for a true comparison.
The first set of tests were for 5 minutes on 40m into a dummy load.
The second set was on FT8 CQ into a dummy load, until the FT8 watchdog timer terminated transmissions.
No Shroud Ambient After 5 Min Xmit Temp Gain
Fan Off 81F 128F +47
Fan On 76F 94F +18
With Shroud Ambient After 5 Min Xmit Temp Gain
Fan Off 83F 128F +45
Fan On 81F 98F +17
Operating for 5 minutes into a dummy load suggest that a fan is probably as good as a fan and a shroud.
On FT8 CQ (into Dummy load, until the watchdog kicked TX off):
WITH Shroud Ambient After 5 Min Xmit Temp Gain
Fan Off 84F 105F +21
Fan On 82F 88F +6
Of course the missing measurement is the FT8 CQ with just a Fan. Mark thought of this test *after* he had put everything back together. 🙁 .
