ysgm232508 2.4ghz vco EDIT: now ADF4350 THREAD!

[drspastic]

has anyone played with this part for anything other than a jammer? im interested if it can produce a stable output frequency given the right conditions. the acuracy of the frequency is not so important as i could lock the control voltage to a known source.

heres the datasheet:
http://pro366bdc.pic21.websiteonline.cn/upload/InnotionYSGM232508Datasheet_V3_1_HS_20230825_oczr.pdf

i dont have a spectrum analyser, just a nanovna saa2 so i can see output but not really judge it. it seems really noisy.

[RadioNerd]

There is not much information in the data shert but being a rather wideband VCO the phase noise of the part wont be exceptionally good...
However it is looks like a goood part to be used with a PLL IC...

[eb4fbz]

Such a free running VCO is highly unstable. It will wander a few hundreds of kHz and drift more than 1MHz away if temperature drifts a couple of degrees. It’s essentially useless without a PLL for other than a sweeping jammer.

[drspastic]

i have just ordered a ADF4350 module instead. this should give me a far better output although coding is going to be even tougher. theres only some amateur libs on github and i dont know how easy they will be to use.
what i am hoping to do is have a dual vfo type arrangement where i can set the frequencies independently with buttons and oled display. a gpio would swap vfo1 frequency and vfo2. this way i can use the same osccillator module to downconvert 740mhz to 29mhz, and upconvert 29mhz to 2.4ghz. this way it can function as an add-on box for usdx to operate qo100 in the field. websdr can be used to callibrate the local oscillators before each session.
the nanovna saa2 uses this kind of oscillator and my tests show it is stable enough. a temperature controlled housing would be used to finish the project.

[10maurycy10]

Generally, all VCOs are quite unstable. They will drift many MHz with temperature, supply voltage, output matching, etc. On it's own, it's not usable for much more then a wideband jammer or perhaps an FMCW radar. (where the same oscillator is used to transmit and receive)

If you want something usable as a transmitter its going to have to be run as a PLL, locked to a stable reference. With some modification, a PLL can also generate very nice modulation, keying and chirps.

[drspastic]

so at long last i have the adf4350 board, a selection of esp boards (conveinient 3v logic) and displays. also a handful of different input controllers.  i think i will go for analogue joystick with click switch as input, 1.8" tft spi display.
i am already over my head and thinking about trying to find someone on fiverr to code it although i havnt had much luck the few times i did that before.

what do you guys think a fair price to code the project? i want 2 vfo memories displayed on screen, each activated by a gpio and adjusted and selected by the joystick. i want to leave it at that so its a building block and i can add a second mcu to modulate it or whatever. its already looking like its using most of the pins on a lolin lite.

any suggestions as to good guys to look for who understand boards like the adf4350?
its often an ache to explain to these people anything more than digital io pins and leds.

shall i open this as a new post or leave it here? its run off topic a bit now my main board has changed

finally, about external reference: i was hoping not to need one if i place the project in a temerature controlled box. i have some nice metal cases to upcycle and some peltier chips. i dont mind tweaking frequencies by hand every so often. i dont like the idea of relying on gps satellites just because. but i dont mind getting a ocxo if that would substantially improve on the boards tcxo. i have used the cw output on the nanovna 2 and that seems stable enough on the uplink.