Chromecast query

I don't think I have whole picture but the orientation of the chrome cast dongle should not matter.
If you are moving it away from the other devices because of interference then try and have it's cable crossing any power cables at 90 degrees and avoid running parallel to any power cables or anything that has a decent AC signal in it that could generate an electrical field ( induced hum ).

If you are trying to optimise the signal for the Chromecast you could always use an ethernet adaptor:
https://store.google.com/au/product/ethernet_adapter_for_chromecast?hl=en-GB

If you want to stick with WiFi then download one of the signal analyzer apps and check how good your WiFi is at the location, you may be competing with other channels or even other higher power signals like maybe your neighbours AP ?

I'm not sure what Wifi extender you have but the ones you plug into power points are good for basic web browsing. I tried this when I moved into my house and my computer maxed out at 2MBps download whereas I was getting around 18MBps when close to the main router (pre-NBN times).
Ended up running cat 5 down the side of the house.

I'd get a wireless access point (or another router if you have one lying around, but you'll need to configure it as an access point) and hook that up closer to your chromecast with a long network cable back to your main router.
Also remember that the longer HDMI cable and the more joiners, the more chance the signal will degrade to a point where it doesn't work.
Another option is to get a HDMI to network converter which will allow you to maintain a decent HDMI signal over a longer distance by using network cable, so you can move your chromecast closer to the main router.
Or you could shell out for a fancy Wifi mesh system.

Do you really need the extender? I've found them more trouble than benefit. Where in the house is the modem/router and what type is it?

We don't have a huge home, but it is long, and with the modern/router in the middle it services all our needs with 6 adults regularly here, lots of streaming, some gaming (Telstra Smart Modem II on NBN FTTN)

Oh, and orientation of the CC doesn't matter, assuming a decent wi-fi signal

Originally Posted by Moondog55

It's a D-Link but I've just ordered something a little faster; just in case.
Cable would be preferable but I wasn't thinking about home theatre or computer connectivity when we had the plaster off.
Getting under the house now means using the floor access hatch and we now have a floating floor covering it

if your existing extender meets the N300 standard, then it'll be substandard in meeting today's requirements. Maybe the new one will be better, I hope its AC1200 or higher, generally north of $100

Any excuse