| Electronics > RF, Microwave, Ham Radio |
| Waveguides for Hobbyists! |
| << < (3/4) > >> |
| joeqsmith:
Link to Maury Microwave WR90 calibration standards user guide: https://maurymw.com/wp-content/uploads/2023/12/WR90-31.pdf If you read all the posts in that thread about calibration, while there was some suggestion that my math was incorrect, Solver uses the same format as Agilent and I attempted to use their math. As of today, I am not aware of any problems with these calculations. The newer released versions of Solver support waveguide calibration by selecting the waveguide connector type. |
| bingowashisnamo:
Hi Joe, yes now I remember that video. It was a short, offset short and load calibration. That's cool that you implemented that in your software. I will try it out as I plan to build other types of waveguide components and being able to de-embed past the coax-to-waveguide transformer will allow for better characterization of the component. Coppercone, I understand why you don't like tape. It's not at all professional. It is strictly for amateurs or if used in a commercial setting just for temporary debugging. What tape does offer the hobbyist is a combination of acceptable conductivity, its inexpensive and easy to use. For the hobbyist who is playing around with prototypes that's a good combination. Argyll, I like your patch antenna! Did you feed it with some resistive or reactive dividers? I think your idea about the horn and reflector would work. A horn has very small loss to begin with so the added losses from the application of copper tape would be minimal to the overall system. How would feed the horn and would this also be for the 2.4GHz band like you patches? |
| mr ed:
I tried soldering and taping together brass to make horns, copper tape etc. for waveguides but was never happy with the results. As I wanted to join the 100GHz club I decided to go more or less pro and make proper brass cavities and the like. I also decided to avoid any commercial guides entirely. That's why I decided to learn enough FreeCAD to make my own hardware. Freecad can be daunting as there are unwritten design rules and drawing approaches you need to learn. Bugs Too. But, simple rectangular bits and pieces are easy enough. Also, in the mm range the parts are small and cheap to mill. So, for 24GHz and above (wr-42) it's not so expensive. Those of you with a machine shop are all set. Brass is easily polished smooth. I figure 20 hours on Freecad (or fusion) would be enough for basic waveguide work. This brass work (https://groups.io/g/TekScopes/photo/270729/3849179) was under $100 offshore. Its 0.1mm accurate by spec but possibly better so it would be good in theory to 250GHz! This one has a built in horn exsentially for free. Have you priced out commercial horns? Eye watering $ for the ultimate performance which is not needed to experiment with. So, go modern go 3d, go brass milling and go crazy. |
| coppercone2:
I figure the reason why people are interested IS the irregular structures though, I guess I never thought about it from a "make a QSO" prospective that you have. I figured most end game would be some thing real weird, which is why I put alot of effort into these obnoxious manufacturing techniques that may have some unique capabilities if they are mastered, but its alot of stress for slow results lol but on the other hand if you can't make standard parts its like not having good test leads for a experiment which makes it ultimately fail. But there is another aspect to this, that is simple parts with bad aspect ratios for machining, but I guess that is not a problem unless its a serious installation Especially with high frequencies, the connected at the end seems not achievable with machining techniques, I think there is a giant wall there, but I am seeing that there does not seem to be a good way around it, you need both machining and the 'other' techniques to be practical/high quality. The machining part is difficult to learn and time consuming but somewhat standardized and approachable, the other part is a total crap shoot perhaps you are right that machining is the way to get some of the system running, but the other part is necessary. I am not convinced that you can get away from machining by only using the other part, but it seems like the way most people would try to do it because in theory its alot easier to plate something or what have you, but I am seeing nothing but obstacles trying it that way. machining everything that can be machined is going to make the errors go way down, unless you truely master some exotic manufacturing methods. But, it depends on the experiment, some experiments are so insensitive (or sensitive if you think about it conversely) that it almost does not matter if your hookup is crap, and some experiments are the opposite where you won't see jack shit unless the rest of the system is NIST grade. However, given that the MMWAVE test equipment (calibration? whats that) people are likely to have are already going to be dodge city, having the best hookup possible probobly will help lol |
| joeqsmith:
I don't have a lot of interest in experimenting with communications. The closest I got was measuring the radiation patterns from those printed horns. Making a working EPR spectrometer required a load, tuning cavity, iris, hybrid Tee, isolator and two coaxial transitions. There are some benefits to working beyond the X-band like I have demonstrated but I can't see custom making these parts. |
| Navigation |
| Message Index |
| Next page |
| Previous page |