looking for RF/microwave/antenna projects to work on + project idea - Page 1
Forum section: electronics / rf-microwave

author: jsr38
author_rank: Newbie
timestamp: May 06, 2017, 03:32:42 am
content: Some background first. I'm qualified BE EE some years ago, more than I care to admit, and have ended up working in software for a long time. I'm back at school warming up to apply for a taught masters with a focus on RF, microwave and signal processing. I'm looking for some projects to back up the book learning with.I've have an idea for a project which is super-complicated and involves antenna array, well, two or three elements, some signal processing for direction finding (MUSIC) and some smartphone interfacing. Apart from all that, the antenna will not be a typical type having certain polarisation rejection properties and the array as a whole might need modelling. To prototype the system sounds like using a multiple channel pre-built SDR such as a LimeSDR is probably the most sensible thing to do in terms of time and effort.That project is possibly over-ambitious given that there are several areas of expertise involved and there's only one of me who can barely generate and run a NEC antenna sim and interpret the results, although everything from the external PC/smart phone interface I'd have no trouble with. I have a rough idea about how the RF front-end might work and know about existing signal processing techniques that I think fit the bill but I don't have in-depth knowledge of either the RF side or implementing the DSP on an FPGA. Even getting some pointers about simulating an entire array antenna using MoM codes would be great but I think this is not generally the sort of stuff that a local Ham club could help with but there may well be exceptions.I see there is "RF Blockset" for Matlab which appears useful for simulating the complicated project I have in mind but I can't justify the price tag. Maybe someone is interested in creating some equivalent for use with GNU/Octave that might build from existing projects?Given the project I have in mind is likely of the "biting off too much at once" variety, is anyone aware of any interesting open source RF and signal processing projects that have relatively simple, self-contained tasks that could be worked on by an 'intern'? Things like filter design (all though I gather most people would pick filter modules from a vendor these days), implement a particular GNUradio processing block, implement some signal processing in an FPGA?I don't have access to commercial tools but I gather that there is plenty that can be done with scikit-rf, KiCad, Qucs and necpp (MoM) codes which are all in the public domain.Apologies for the rambling nature of the post... I'm kinda just throwing the ideas out in the hope there might be others wanting to make the jump from knowing a bit of theory to working on a project or very experienced people who can suggest some things to try (or even interested in working on the complicated project!).All the best.

author: radiogeek381
author_rank: Regular Contributor
timestamp: May 07, 2017, 07:23:50 pm
content: As you've been working as an engineer for a while, you know that the more involved a project, the more involved the unforseen problems that will crop up along the way. Given that your goal is to learn more about the RF and signals side of the problem, adding pieces that aren't necessarily along those lines almost ensures that that's where you'll spend most of the time and problem solving.Perhaps a less ambitious plan might be in order? I could suggest a few.1. If you want to understand demodulators, write a LimeSDR application from the ground up, using SoapySDR (rather than gnuradio) and build something that demodulates FM stereo and captures the digital signal that piggybacks on the carrier. (This will get you to work through some interesting issues in demodulators.2. If you want to grapple with some of the problems in weak signal detection and RF artifacts (intermod, out-of-band signals that swamp the A/D, RF oscillator spurs) build something that demodulates one of the weak digital signal schemes on the ham HF bands. (BPSK would be a starter. I'd avoid trying to re-implement WSJT type modes, as you'll spend a lot of time on software issues rather than RF.)3. If you want to work on very weak signal reception, try building a receiver for one of the microwave ham bands to listen for echoes from the moon. This is the most ambitious of the suggestions regarding the RF side, as it gets you into the dark-teatime-of-the-soul regions of low noise amplifiers and high gain antennas.4. At lower frequencies, detecting some of the WSPR beacons either on one of the HF frequencies (noisy RF environment, lots of man-made interferers), VHF frequencies (man-made noise, intermod from commercial broadcasts), or UHF/microwave (weak signals, interesting LNA design problems, fun antennas).I hope this helps. Again, if the goal is to learn about RF, keep the scope of the project small and dominated by RF issues.Even at that, I've been an engineer for a very long time, and almost every RF project spends more time on the power supply than I had intended.

author: jsr38
author_rank: Newbie
timestamp: May 08, 2017, 05:17:27 am
content: Wow!Thank you evb149 and radiogeek381.It seems I constructed the post, posed question(s) and posted in the correct forum in such a way that I got exactly the sort of input I was after! Hooray!I'll formulate proper replies to you both once I've had time to consider them, and yes, I can answer in quite some detail evb149, regarding some of the points you raise. I was worried the post was already too long. TL;DR effect.Yes, well aware of FDTD (MEEP), and I have some experience driving commercial FEM tools (ComSol). Timescale is medium >1 year. As I say, I'll structure my thoughts and get back ASAP.73's as the Hams say.