Warning: HDMI-to-VGA converter conflicts with WLAN-connection

Hi all,
maybe this is of interest for others, too:
I always wondered why I can only hardly get a connection to my WiFi
router when running Rasperries -- Zero up to 3B+ -- in desktop mode, but
there were no WLAN issues when running as ssh server.
For doing this I formerly used an HDMI2VGA adapter (cheap 10 $ thing) and
it did work. But I recognized that it got really warm, and so, I
suspected that this energy came from the PC and not from the monitor.
I measured USB voltage output and found out that connecting this "adapter"
will cause the output to go from around 5.2 V to 5.1 or below.
This seems to significantly interfere with the internal WiFi module, and,
hence, when connecting the monitor with the Raspberry using a "normal"
HDMI-to-HDMI cable with no conversion, then the problems connecting to
WLAN router were gone.
This just to say in the case that other people see such issues, too.
Best regards,
Markus
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Reply to
Markus Robert Kessler
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Connecting anything to the HDMI port causes an increase in power usage. A few of my Raspberry Pi's are connected to TV's, and I see an increase in SOC temperature of 4C when they are switched on.
I've not noticed any issues with the internal WiFi and just a TV connected, but a HDMI powered dongle would be likely to affect it more than just a TV.
---druck
Reply to
druck
I have broadcom chipsets in my laptop and in my Pi Zero. Both display on reasonable signal levels and reasonably CONSTANT signal levels massive variations in wifi speed - from 1Mbps to 54Mbps.
My conclusion is that broadcomm chipsets are total crap - at least under linux.
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Reply to
The Natural Philosopher
Not seeing a problem here with a P3 BENFEI dongle from Amazon and a 3A PSU
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W J G
Reply to
Folderol
Am Sun, 17 Feb 2019 13:31:00 +0000 schrieb Folderol:
"BENFEI"? With active power in? Like this one:
formatting link
B01KLKQN9U/
Yes, sure this might solve the issue -- mine is not actively powered, because I was not aware of such problems when ordering...
Good lesson -- thanks!
Markus
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Reply to
Markus Robert Kessler
Actually, I've found it will run quite happily without external power :)
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W J G
Reply to
Folderol
Am Sun, 17 Feb 2019 15:56:49 +0000 schrieb Folderol:
Hi,
same here as long as my router's WiFi signal strength is high enough. If I am willing to increase it to 100% maximum I also get connected while RPi has to power the passive HDMI-VGA-converter.
Without converter, or, probably with an actively powered converter, 25% output power are sufficient. This prevents me from being toasted, and so I prefer this solution...
Best regards,
Markus
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Reply to
Markus Robert Kessler
You do know that your WiFi wont toast you or anything else at 100% power, which is 100mW @ 2.4GHz. You are just about as likely to be blinded by the blinky light on the front of the box.
---druck
Reply to
druck
Some of the blue power LEDs they're putting on devices these days are waaaay too bright for the purpose and often do blind me in a way such that their glare makes it harder to see other things nearby. I end up putting masking tape or something over them to diffuse and reduce the light. (ofc "blind" is in no way literal or damaging here)
Reply to
Joe Beanfish
Sing it, brother! Back in my theatre days (about 15 years ago), I once put three layers of masking tape over the pilot light on the sound board so I could see anything else in the darkened hall. More is _not_ better.
And why blue, anyway? It's too piercing, and my eyes can't focus on it. It's just one of those fads which I hope eventually passes.
Don't get me started on automobile headlights...
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Reply to
Charlie Gibbs
Band congestion could be an issue.
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Michael J. Mahon

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