42 - Mixers & Modulators
ฝัง
- เผยแพร่เมื่อ 11 ก.ย. 2024
- Nick M0NTV revisits the topic of building your own diode ring double balanced mixer/modulator. This time we check out what works best to get the kind of performance we want to see.
For good explanations of how the diode ring mixer works please see:
• #167: How a Diode Ring... (Alan W2AEW)
• RF tutorials - Diode b... (Fesz Electronics)
soldersmoke.bl... (Bill N2CQR)
Practical details and schematics will be available with the next video.
Enjoy!
Nick, you may not be "an expert" but you're utterly brilliant!
And your joy really makes these videos priceless.
Thank you so much. I'm learning a ton.
Thank you so much for your kind words Mark. I'm really pleased that you find the videos helpful. Happy Christmas and 73, Nick
Dear Nick, you are a natural-born teacher. TNX for the video! I love how you explain something complicated in such a practical simple way. Have learned a lot from this video and will wacht them all! The downside for me is that I now realize that my homebrew stuff isn't as good as I thought. Keep it up Nick.
Thanks very much Danny. We're all learning all the time! Don't be too hard on your home-brew creations - they are all part of the learning too. Frankly I'm amazed some of my first radios ever worked at all. Keep up the good work. 73, Nick
The Si5351 is made to drive Cmos loads. The termination of mixer and generator is important as during the cycle they would be momentarily in no-man's land. An attenuator is a good idea, and using a diplexer is a great idea. Great improvement. Makes filtering of Carrier much easier with a less than ideal filter.
Thanks very much. That's helpful input. 73, Nick
I have not got to the end of this video yet but from what I have just seen, this is one of the best instructional videos detailing how to implement mixers and especially modulators. Great work!
Thanks very much indeed. 73, Nick
Wow, what a difference the matching made! Being able to show the various stage results on the spectrum analyser is a great help to viewers and learners. It's great to see how these elements of design fit together to give the desired result.
There are so many vicar jokes, they must be almost an occupational hazard. 🤣 Thanks for making this video and have a great holiday.😆👍
Cheers Ace! 73, Nick
Nick, this video is pure gold! I watch so many similar channels that you probably also watch, but your comparison of the different improvement steps you went through is second to none. Have a great holiday and looking forward to the next videos. 73 de Cedric ON4CKM
Thank you very much Cedric. That's very kind of you. 73, Nick
Brilliant mate! Great step-by-step of your findings.
Cheers Al! 73, Nick
Impressive work with new insights for me. Thanks a lot for it. Can't wait to see the next video on this topic.
Thanks very much. Pleased it was of some interest. 73, Nick
Yes, I think you've got something here. I'll have to look at the uBITX V.6 schematic I have on my wall to see what Ashhar did.. I do know he used the BAT54S Diode Array Schottky which is basically two schottky's in a single package surface mount, and used two for a ring. I'd also like to know what the 7300 does as I can hear carrier and I don't think mine is balance well. I'm also looking into replacing the diode system in a very old radio, a swan ss-200 to see what I can do with it. That said, the original had a way of balancing it so maybe I should leave it alone.
Been trying to get back into home brewing but this time with test-equipment that I lacked before so will be keen to replicate some of your experiments.
I hope that you will show your design methodology for both the diplexer and the impedance matching (which I assume is some kind of L-network).
It was often said by Doug DeMaw that you could build superior equipment using simple designs by paying strict attention to detail; your demonstration really brought that home in that you attained superior performance to the commercial mixer which is so coveted by homebrewer hams these days; I remember stripping a few of these out of satellite receivers myself. Long ago, when I would visit hams that built their own equipment, I was often taken by how incredible the fidelity of their audio, both clear and full-range.
Another time when a ham remarked how the Drake audio had a great natural sound, another ham remarked that if you look at the Drake circuitry, on the surface there isn't anything all that earth-shaking but they did pay extreme attention to details among them careful interstage impedance matching that mostly goes unnoticed.
Just ran across your channel and subscribed; will also look at you other videos including the mixer ones mentioned. Thanks for putting these out! 73...
Thanks very much for watching, commenting and even subscribing. I appreciate that! Yes, the RF diplexer is covered pretty comprehensively in that video I recorded last year. I will mention about the Z match transformer though. All the best with your own building and experimenting. Thanks again. 73, Nick
This was a very useful video, thanks for making it. The impedance matching on the LO at the end was neat to see. I am looking forward to schematics in the next one -- I'd like to see how you applied the diplexer on that port.
Thanks. The diplexer I used is almost identical to the one I built here: th-cam.com/video/IPf8Z2ElSos/w-d-xo.html 73, Nick
Really nice video, explained very well. Waiting for the diode matching video. If I can make a suggestion, investigate on matching the best you can all the ports, digging very deeply in it. You have already noticed that it matters really heavily. Thank you very much. 73 de IZ4HDM Cristiano
Thanks Chris. Funnily enough I had tried using diplexers on all the ports - except the LO ... until now! It was an eye-opener to see the difference it made. Thanks and 73, Nick
Really good. Many thanks. 73 Ellis GM4GZW
Thanks very much Ellis. Glad it was of some interest. 73, Nick
looking forward to the schematics next time, Mike, EI6AU
Cheers Mike. 73 Nick
That plane vanilla mixer is used in the VEGA Selina.
As for the LO impedance match, you could use a simple emitter follower and suitable emitter resistor.
Thanks Chris. That's something I've not tried. Thanks too for the positive feedback. 73, Nick
I was hoping you were going to slap a 120 ohm resistor across the output of the SI5351 to see if the improved match did the job even though the waveform was still square.
Hi Nick, I can’t find any information on the internet regarding the audio diplexer. the schematic can be traced from the video, but the values can't. If you could reveal the values of the components, I can finish this part. Thank you in advance.
Hi there! I think all you need is in video No. 34 - Improvements to the Direct Conversion Receiver (th-cam.com/video/xYY_rAS8cyk/w-d-xo.html). There are links in the description too. Hope this helps. 73, Nick
@@M0NTVHomebrewing Thanks Nick. I didn’t realize that I have to watch all you video’s (Hi)
Now I can finish the complete IF and AF sections, almost a receiver.
Thanks again 👍,
Gerard
No worries Gerard. All the best with your building! 73, Nick
Hi Nick,
You talked about a diplexer for the LO, did you actually build that? Is the bandwidth of the diplexer sufficient for the wide range of the LO. A band pass filter can be designed with 85 ohm input and 50 ohm output, wouldn’t that do the trick as well?
Hi Gerard! Thanks for your questions. Yes, I built the one identical to the diplexer in my previous video: Diving Deeper Into The Diplexer. It is by nature a narrowband filter which is useful as I'm only using it on the LO port of the balanced modulator (the BFO). So this is one fixed frequency - 13.3 MHz. As I've said before, the advantage with a diplexer over a regular LC bandpass filter is that the LC filter will see a good impedance match over the bandwidth of the filter but a pretty terrible one outside that: whereas the diplexer sees 50Ω irrespective of frequency. Hope this helps. 73, Nick
I can hardy wait. I have a few thousand surplus FH1100 mixing diodes just waiting for projects. I'd love to see how you match them so I can do the same.
They will come in very handy!!!
I am intrigued by the wiggly traces on Andy's board, I'm guessing some impact at VHF UHF. Can anyone enlighten please? Thanks.
Andy might see this and answer himself. I've tipped him off that he gets a mention! 73, Nick
He is probably keeping the track lengths equal for use at higher frequencies. You want the propagation delay to be the same. Not so important at HF but can be very important at VHF
Two reasons, the track lengths vary a bit due to the connection point on the ring, so I was trying to make things all the same. The second reason was that the track length adjustment was a new(ish) feature in Kicad so I gave it a try 🙂
At normal HF freq it makes next to no difference.
The other feature of the boards was to make the connection of the cores a bit easier. I always got annoyed in trying to sort out the wires then routing them to the correct point on the ring. The boards take care of this so you simply connect the start of each winding to one side,, and the finish to the other. The PCB tracking takes care of the rest.
Once I have a few more testing results done I intend to pop the design up on somewhere (github I think) so that anyone can get some boards made up if they fancy doing so.
Currently I've been sidetracked into writing some software to get the 5351 working on the Raspbery Pico using MMBASIC it's getting closer...
Andy G0POY
@@andye2005 Thanks Andy, appreciated.
If you don't match the L-R-I impedance's on a commercial diode ring mixer performance will hands down suffer. They are good at what they do, but they are finicky that way.
Hi Brian, I think you are right. To be honest I've only used commercial mixers twice in my homebrew transceivers. They are great for saving space but I prefer to roll my own diode ring mixers really. 73, Nick
Hi Nick,
... what does it mean, when you are telling: "...dickings of a job, ..." (timestamp:17:00 )
I'm not a native English spoken person, would you please help me?
Sometimes you 'surprised' me, a lot, ... ! You have to know, ... also the 'translation' has no glue, what it means, ... and me too.
Be so kind, and help the 'knowless' people around you, ...
I 'm impressed, that the results are so good and waiting for the next videos, ...!
73 de Markus - db9pz (JN39fq 3miles/5km, east of LX)
A 'dickins' of a job in this case means 'very difficult to do'.
@@johnwest7993 Thank you, ... that's a problem as a not native English speaking person! Sometimes we 'missed' some rudimentary items, we do not learn so easy.
73 de Markus - db9pz - in the very south-west part of Germany, beneath Luxembourg. (JN39fq)
@@markusm.lambers8893, it is an occasionally used expression, not a foundational term in the language, easy to miss. I'm just thankful for all of the web-based translation help we can get.
Thanks Markus. John beat me to it but sorry - my videos are probably littered with colloquialisms (i.e. phrases that are used within a culture and language but which do not translate easily into other languages). Thanks for persevering! 73, Nick
@@M0NTVHomebrewing Apparently 'Dickins" has no connection with the author Charles Dickens. One explanation is that it is a euphemism for the Devil or Old Nick.
By the way my Arduino based Si5351 is working! Mike, EI6AU