Another toy at home: UBITX transceiver.
The µBitx is a HF (3-30MHz) all-band SSB and CW transceiver kit. It is supplied as a completely pre-populated and tested circuit board by the manufacturer (trading as HF Signals). The purchaser needs to assemble the board into an enclosure and wire up sockets, encoder and potentiometer and provide a power supply in order to get the transceiver working.
The receiver is a double conversion superhet design with a first IF and 15kHz roofing filter at 45MHz and a second IF and 6 pole Coen crystal filter at 12 MHz. The receiver has excellent rejection of unwanted signals above 30MHz at the first IF as it also has a 0 – 30 MHz 3 stage bandpass filter. However, if you live close to high power AM Medium Wave broadcasters you may have issues with broadcast interference. The receiver has no AGC, and no RF gain control, which does present as an issue at times, but is nice and clean, with few birdies and nice sounding audio unless the AF gain control is wound up high. The transceiver can work on both side bands (LSB and USB) so is fine for use with digital modes. Software is already available to provide CAT control and WSPR modes within the transceiver.
The transmitter gives output of up to 10 watts PEP on SSB and 10w continuous output on CW at least on 40m. Output varies by band. Output on 80m will be greatest.Performance falls off with frequency. You can expect around 4 watts on 20m and 2 watts on 10m.The transmitter follows the same approach as the receiver, with the microphone amplifier feeding into a mixer at 12 MHz and then mixed up to 45MHz and then to the final transmit frequency. The exception is on CW transmit where the 1st local oscillator is fed into an unbalanced mixer to directly excite the pre-amp stages. The microphone amplifier may not always provide adequate gain, depending on your chosen microphone. The drive control can be adjusted to increase SSB (and CW) drive, but be cautious that you do not overdrive the finals, causing IMD products and distortion, and potentially damaging the finals in the transmitter.
My Ubitx was comig from a friend who build it in a small cabinet. But not good at all with some mistakes.
I build it inside an old Computer cabinet:
Nice cabling and it runs very fine !
Chinese S’meter for 15€
On my first Bitx40 i added an analog smeter with simple circuit on audio line and a 500 microA vu-meter.
Al was fine except that without AGC it is just a signal level.
On my Ubitx i have added a Chinese Audio Vu-meter that is better…
Around 15€ with a circuit and 2 vu-meters.
And with the input circuit it is just like an AGC.
For fun i have nice warm lights..
And for the same price you have another Vu-meter and a second input….
sevral shops in China.
For axample: https://fr.aliexpress.com/item/2-Pcs-VU-Panneau-M-tre-Chaud-Back-Light-Enregistrement-Durable-Pilote-Conseil-Module-C-bles/32845258857.html?spm=a2g0w.10010108.1000014.4.7f4136c0wSoVBV&scm=1007.13338.98644.000000000000000&scm_id=1007.13338.98644.000000000000000&scm-url=1007.13338.98644.000000000000000&pvid=52300d9e-a326-461a-bc52-4ef4dd0f467e&_t=pvid%3A52300d9e-a326-461a-bc52-4ef4dd0f467e%2Cscm-url%3A1007.13338.98644.000000000000000
(the hole in front panel is not perfect. I am going to make a new panel…)
A mezzanine for futur extensions
A small China power supply for some euros…
Ready to stay at home with 220V or on the boat with 12v…
Ubitx versus other rigs at home . Heathkit HW101, Collins 51S1.