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Farhan, What you say sounds right. There's a reason why people have moved away from analog VFO's, they are finicky. The Si5351 is not necessarily the best choice, just the cheapest and easiest, so it

Jerry, Contrary to a popular opinion, a free running LC oscillator can be the quietest there is. Any attempt that holding it to a frequency (phase locked loop) starts adding to the phase or amplitude

Hello, the project of a Ubitx in module has already been evoked see here: /g/BITX20/topic/71823431 cdt

Gordon, Any assembly can be cut into pieces. Advantage, one can change/ improve a module at its convenience. The best system (in my opinion) is a board with main functions and a bus with several

Farhan, What do you think is the major factor in the relatively poor performance of the Si5351? I suspect it is jitter, not the fact that it is a square wave. The Si5351 is their cheapest part at $1,

Ashar, I agree that a analog vfo would be superior but I have not had much luck building one that was stable enough. That was the reason I chose to use the 5351 or my PLL. Any chance you would share

Barry, I too built a direct conversion transceiver a few months ago. I chose a fully analog design without any ICs. A carefully designed free running vfo is used. It is so stable that I can

Hi fellow DC rx fans. Back in 1992, Rick Campbell had a design in QST for a direct conversion receiver he called the R1. Later he upgraded this to the R2. I have the R1 that I have used the si5351 to

Thanks, Evan, you’re always on the cutting edge of information. I note this aside for my next changes Have a good weekend

Thanks Evan for the help. I had been searching the CEC sketch instead. My TXR already uses a 2X16 display and I was hoping to upgrade to the Nextion. My TXR uses 2 swithced? 2nd IF oscillators for

Bob: My spare Raduino worked fine for that purpose feeding a 4SQRP ZZRX-40 DC receiver. Heard all states from Florida on an indoor wire. James KE4MIQ

Gerard, I went back and looked again.? I believe that F5NPV is also using the standalone signal analyzer option from KD8CEC.? That is a second Nano connected via the I2C lines to provide the "small

Hello, Thanks An other link https://ubitx.net/tag/aj6cu/ cdt

Hello, According the NEXTION file i am using the one from AJ6CU you can find here in the file section. as far i can recall , this is the only file i test and i am using enhanced NEXTION? display.

Would be interesting to try sine wave vs square wave. But I doubt you will notice much difference, Assuming you have a low pass (or band pass) filter on the RF input, the harmonics in a square wave

There was some comment in the webpage about the signal being a square wave. If this shows up in the signal, causing harmonics, then included in the amp should be a "smoothing" circuit or some way to

bob, i have used it as a local oscillator. but there is a catch The primary purpose of the RF out was to be able to measure the frequency response by feeding the RF out into the device/circuit under

After rereading the specifications for the Antuino and its oscillator stability, I suddenly wondered if the oscillator can be used for the oscillator in a Direct Conversion receiver... Perhaps there

Good news. Thanks. That's a clincher for me. Bob — KK5R

My Antuino came fully assembled in the enclosure shown.? The screen may be different depending on the version of software that is now being supplied by HF Signals 73 Evan AC9TU