hey man i really love ur videos. ive actually dedicated the last 2yrs of my life and many thousands of dollars to be able to learn to do some of the the things you’re doing in your videos like the 16ghz mixer. i was wondering if there are any groups i can join to talk to you or people like you and learn from. im interested in mmwave diy projects. i have 15yrs software engineering experience but am 2yrs new to hsrdware. i have like a million questions for someone like you, as the info you have is almost impossible to learn about online, seems mostly skills learned through doing and passed around in ham/satellite groups. found it very hard to find info (e.g u have the only mmwave diy mixer video on youtube). i dont know enough about electronics yet to just learn everything from reading schematics online but am trying
Thanks for the comment Zacki, I appreciate it. In fact I am not aware of groups sharing information on microwaves experimenting, except groups dedicated to amateur radio bands and how to put together modules to establish a communication link. The fact is that I started the channel just because of what you said, apparently there's a void in this area on youtube. I try to get some information from academic publications, instrument manufacturers publications, watching good youtube channels like The Signal Path, Microwaves and Machinig, etc and so on. I am currently studying a way of expanding the range of my 18 GHz spectrum analyzer and frequency counter to 30 and hopefully 40 GHz and I expect to be able to make a vídeo covering this subject in the future. Again, thanks and feel free to contact me (vk5fe @ wia.org.au)
@4:40 the output voltage is higher when 2A is drawn compared to no load! how? same thing happens at @5.25 for the other samsung. interesting...i wonder what is their design
Cool, but on the other hand, you could simply slow down the timebase on the 'scope to get more waveforms on the screen to increase the resolution. I can easily and completely separate two tones at 1000Hz and 1005Hz (with levels shown in dBV) on my cheapish Siglent 'scope's FFT.
True, you can have better tones definition changing the timebase, my bad. However, the dynamic range is about 30 dB better using the spectrum analyzer (at least with my instruments) and it's easier to measure. Thanks for the input.
Impressive! I must admit I was skeptical at first, because a good sound card can achieve close to 100dB dynamic range, with the frequency resolution basically only depending on capture length. However, it seems your project can easily match that performance, and on second thought that’s not too surprising with the high quality, low noise components you are probably using. One question though, why the attenuated followed by amplifier stages? Wouldn’t that just introduce more noise?
Thanks for the comment. The noise contribution of one attenuator pad is about 0.0203 uVrms (-140dBm) for a BW of 500 Hz (span chosen), so doesn't impact much on the measurement, also because there's also the noise contributon of the generator and amplifiers. The timebase phase noise is about -150dBm@100Hz. The attenuators were introduced mainly to adapt the levels, but the second attenuator has also the function of providing a consistent 50 Ohm resistive load to the mixer, minimizing reflections.
Any reason why you chose the DC decoupling inductors to have SRF above the operation frequency? I think that it shouldn't matter where the SRF is, and the absolute impedance is really what matters. I.e. it shouldn't matter whether it looks like a capacitor to the RF pat, as long as the absolute impedance is high enough. to isolate.
Yes you are right, what matters is the impedance, but I normally prefer using inductors with an SRF not far bellow the maximum frequency used. The SRF, in fact, was given just as an additional information. Thanks for the comment.
I prefer using warm white bulbs, instead of cold white, and depending of the time of the day there's no natural light from the window hence that yellowish appearance. I would like very much to have the opportunity of machining gold but I am afraid that's not gonna happen... 😀
As it was only one unit, there are not schematics and gerber files are not available anymore, sorry about that. But it was a simple design, just additional line filtering for the commercial 24VDC switching power supply and a power split at the output. Anyway, if you want additional pictures, just drop me a line.
I love to know where you obtained all that beautiful Rhode & Schwartz test equipment... You are either insanely wealthy or buy broken stuff and repair it...(?) You're workmanship is superb! I'd like to build my own 10GHz setup, you are an inspiration... 73 VK4QP.
I wish I were... I bought the R&S pair directly from them, when the AUD was 10% stronger than the USD (very unusual, I must say) and the spectrum analyser was a demo unit, so I paid about half the price of a new unit. Sadly that generator, with that nice form factor, is not manufactured anymore. Thanks for yout nice comment, btw.
Great videos! but I have one question for you: have a MAX2870, reading R6 and writing registers correctly SPI, but nothing generate (REF 100MHz), no auto select VCO, no AGC value. How i can find the problem? What to do first in this case? Thank you!
Suggestion (if I didn't miss anything): On the MAX2870 power up the fractional mode is set, integer division is 250, fractional division is zero and the doubler and dividers in the input path are disabled. If you apply 10 MHz at the reference frequency input you should have 2.5 GHz at the output A (B is disabled) and the lock signal should be ON. If the output is too high for you to measure, modify Register 4 accordingly. If it doesn't work, consider checking soldering problems. I hope it helps.
@@vk5fe943 thank you! I Have 100mhz refrence now on board.. . The lock Led not work when power up. Only manual set to on off is work. Ref 10mhz gen now travel to me on post. I Will try it, or may be soldering first...
@@vk5fe943 you are using a simply scheme for NAX2871 - can you share it for me? (may be CAD files) i want to create simply gen device with MAX2870, but always seen more complex schemas, but i need simply one freq signal, how on your device. Thank you!
Hi Paul. From right to left: Station: studioadriana.com/vk5fe/?page_id=866 Firefly: studioadriana.com/vk5fe/?page_id=163 15W Amplifier: studioadriana.com/vk5fe/?page_id=172 Auxilliary Unit: studioadriana.com/vk5fe/?page_id=636
RU-vid algorithm brought me here and I'm not disappointed. It would be great if you could share more info on design and testing the products you're showcasing. Just the assembly and making videos shows your workmanship but not the techniques behind the design.
Thanks for the input, Asef. The expected phase noise at 10KHz offset, with a Pfd frequency of 100 MHz and output of 4 GHz is about -104 dBc/Hz. Of course we must add the phase noise increase due to the quadrupler (12 dB). Unfortunately there's the intrinsic phase noise of the spectrum analyzer, which is -106 dBc/Hz (1 GHz, 10 KHz offset) then I am afraid the measurement could be compromised - even so, I will look into that.
Hi Zia. I am afraid the MAX2870/2871 doesn't have a "sweep mode", you will have to program all the frequencies, defining a time interval to set the sweep speed.
@@vk5fe943 Thanks Sir, I am new with MAX2870 i want to genrates 433MHz Freq single frequency . can you provide me the source code. i am using Arduino board. I shall be very thankful if you guide me in this regards Kind Regards
Hi there. Yes, I bought it new from a representative in SA. There isn't a schematic, I just added some additional filtering, a GPS receiver and an external 24V power supply. In my opinion the PRS10 is an outstanding reference.
Olá Fernando, grato pelo comentário. Por enquanto estou só "brincando" com essas bandas - estava pensando em completar uma estação em 10 GHz, incluindo um prato e o transverter (tudo homemade), mas para QSOs em visada. Tem uma turma aqui bastante ativa nessas bandas altas, incluindo satélite e sei que tem tbém um pessoal BR. VC opera satélite?
Hi Tony, the display is the Adafruit 358. The microcontroller is the PIC24HJ128GP, but actually this is an overkill, you can program the LMX using any low cost microcontroller. But there's a problem I don't know you are aware of: the LMX 2594 will be available at Mouser only by the end of this year.
