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Dodgy Maxim Components
May 23, 2012 at 06:53 PM

Just had to exchange five MAX485 EIA-485 transceivers, fortunate enough, I usually have some of these as spare parts. But consider this to be a warning - if you order some RS485 breakout boards from China via eBay and they have MAX485 chips on them and look like this:

... they're just about to fail within the next minutes! I got five of these boards and all five boards failed during testing a ┬ÁC based board that's driven by a RS485 bus. And yes, I'm absolutely sure, it's not my own board or testbed that caused this since I measured everything twice, watched out for transients, etc.

The replacement parts have a different product code (MAX485E, 15kV ESD protection) and while the dodgy chips had a CSA subcode, the newer ones are marked with ESA. For now I don't want to blame Maxim, as these parts are most likely mediocre fakes, but we'll see. If the newer ones fail again, I'll switch back to the TI SN75176B I originally ditched, as I wanted something that draws less current.

R.I.P. Barbara
Apr 20, 2012 at 04:42 PM

I just had to find out, a dear friend and great musician has left forever. Barbara Buchholz, the ingenious theremin artist died on april 10th. I just would like to thank her for some great concerts and off hours during the last years. She had always been a very, very nice and polite person who shed some light during touring and other stressful moments on the whole thing.

Dear Barbara, I wish you the best to wherever you are right now.

Clueless
May 01, 2012 at 02:49 PM

I thought Computer Bild was the worst of all so called computer related online magazines. Seems as if I was wrong - just stumbled across another DIY WiFi antenna article, thank you google, that was worth quite a laughter!

Besides the common rubbish about legal issues with overpowered antennas, the german online magazine PC Praxis appears to have managed describing transmit power through bandwidth. Something like that is usually worth a nobel prize, though I guess in this case, they would want to check their facts again and maybe stop to contract out authoring to the facility management service 8)
Funny enough, they are also very fuzzy about the EIRP, the unidirectional transmit power figure. They claim 100mW to be ok without any further information, strictly speaking - wrong again. Those 100 mW apply only to a totally equal distribution, which is impossible due to the directional behaviour of electromagnetical waves in this band. With real antennas and real directivity patterns you almost always need to lower the tx power (unless the damping on the link cable is really bad), if you care for those regulations.

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