H field big difference in gain
#12
(2016-10-13, 21:20)DrRobin Wrote: Hi,

Surface elevation plots are on-line at http://www.solwise.co.uk/wireless-elevationtool.html

I swapped out my 5v PSU for a USB battery and all of the E field noise at 38kHz and 76kHz disappeared.  I then tried a nice looking 5v PSU with the correct plug from an old music player (creative zen), it looked well made and had a nice big ferrite on the DC cable.  It was just as bad as the first PSU, although the frequency was higher.

I then tried an iPad PSU, which looked very clean.  Then a USB charger I had to buy at an airport when I forgot my charger, also good.  Finally I have a PC in the summerhouse, it's a Dell with a good metal case and high powered USB outputs, that works well too.

So currently my system blue is now plugged in to my Dell.

At the same time, I have also switched off the HP filter, it seem to be turned on by default, and this seems to have increased the signal to noise ratio on both E and H field inputs.

I just need to look at directional loops now.

Terrain plotting link saved, thanks.

Various comments in these forums (fora?) indicate that units from Apple are good. However my quiet one is from TP-Link. Running a PC to power a controller seems a bit OTT, the fans alone will be using more power than the than the controller!  Blues only draw about 350 mA @ 5 V or 1.75 W.

The HP filter has some gain associated with it see the end of: Noise spikes on board, System Blue

The omni / fig 8 combination is sound theory. One 20 turn loop is now a 4 turn loop to get the level of Anthorn down to a level similar to the horizontal loop. If connecting the two loops together makes a noticeable difference I haven't noticed it yet. The other, obvious if you think about it, thing is that the 4 turn loop barely picks up any wanted signals. If it worked to generate a signal to create a cardioid polar pattern I'd put up with that. You'd still get the signals picked up on the horizontal loop. I guess it's not working as the two signals are not close enough in phase/wave form.

May have a bit more of a play, glad I made the array easy to mount/dismount
Cheers
Dave.

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Messages In This Thread
H field big difference in gain - by DrRobin - 2016-10-09, 19:02
RE: H field big difference in gain - by cutty - 2016-10-09, 19:27
RE: H field big difference in gain - by allsorts - 2016-10-13, 22:34

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