this post was submitted on 26 Nov 2023
22 points (100.0% liked)

Electrical and Computer Engineering

865 readers
1 users here now

Electrical and computer engineering (ECE) community, for professionals and learners. Discuss ECE related topics here, for instance digital design, signal processing, circuit analysis, electromagnetics, microelectronics, power electronics, RF electronics, etc.

founded 1 year ago
MODERATORS
 

So I made an antenna based on a design on thingiverse/blog post. IIRC this is some Yagi variant. I did the math and did a bunch of tedious stuff to try and make it a proper project at the time. I do not have a network analyzer, smith charts are for shaman/wEEzards, and radio is the work of the devil. I was looking to extend the range of the 2.4G channel across my house just slightly using directionality. Empirically, it worked at first. I'm here half trying to diagnose, and half trying to understand some fundamental circuit design basics. The 2.4G output has two channels coming from the same peripheral radio chip. Normally these go to the dipole antennas. I used the same micro coax connector and proper coax throughout, with proper grounds/solder station/flux/etc. The continuity tests good still. The router automatically tries to move the transmit and receive signals between the two separate 2.4G channels under normal operation, but it drops one channel regularly now. I can see this on the network status of a connected device, and the drop happens regardless of proximity. I have not physically tested that the dropped channel is the one that had my DIY antenna. It could be a software problem. My curiosity is could this asymmetry cause a common failure mode, other than something obvious like ESD?

I etch, design, KiCAD, toner transfer, photolithography, and Arduino my way around in this space as a hobbyist, but like, I'm too lazy to go on the eevblog forum to ask this formally and radio is magic IMO.

This is the output stage in a bad hand held half ass pic with no attempt to do things like clean off the residue on the chips from the thermal pad that rests over them. terrible-image

top 4 comments
sorted by: hot top controversial new old
[–] [email protected] 12 points 1 year ago (1 children)

Possibly the antenna wasn't tuned correctly to the channel which you have the router configured to use so you had a higher swr than your radio frontend could handle eventually burning it out.

[–] agent_flounder 3 points 1 year ago

That seems most likely. Takes some tuning to get the impedance match right.

[–] [email protected] 5 points 1 year ago (1 children)
[–] j4k3 2 points 1 year ago

I don't think so. The issue has been ongoing for the last couple of months. I thought it was a software problem at first because I started seeing lots of dropped connection issues while streaming that have seemed to get worse over time.

I still have my doubts that the chip is failing because it can work fine for minutes to hours at a time then suddenly cuts out completely for random lengths of time.