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WIFI channels and signal strength


David Pickett
 

"WifiInfoView", the program recommended by Jerry is worth having for the purpose of monitoring local WIFI activity. It is also worth doing a search for articles on WIFI channels to understand how it all works.

As a former microwave engineer, I am perplexed by Brent's problem. I live on the second floor (third floor in US useage) of an apartment block, dating from c. 1850 with solid masonry walls that are 18-24 inches thick, in a busy street not far from the centre of Vienna, Austria. There is a mobile phone shop with a repair facility on the ground floor below me. I installed WifiInfoView the other night. The details of any detected wifi are listed and are displayed cumulatively. The amazing thing is that after running for a couple of hours one recent evening, WifiInfoView had logged no less than 69 different WIFI signals, many for only brief periods. Clearly most of these were from passing traffic: one was identified as a taxi and another as a tour bus; others may have been people walking past with phone WIFI seeking to connect. All were at a lower level than my own. I can imagine that there are even more crowded places than here; but am surprised that Brent should be observing in a residential area that is more hostile than this. If he is in a suburb in the USA, where walls are much thinner than here, this is surely compensated by the lower traffic and the set back of houses from the road and from each other. (I accept that an apartment block in NYC, Chicago, etc may be different!)

My own WIFI is on channel 1 and has an RSSI level varying between 40 and 50 dBm: it works fine, as all the other signals identified by WifiInfoView are at least 10 or 20 dB lower. When I switch to PMC-8 (on channel 6, as delivered) it transmits at a level comparable to that of my own WIFI and I have never had drop outs.

I would recommend Brent to get onto channel 1 or 11, as these, together with ch. 6 are the most highly recommended and certainly, if he continues to have problems, to go with a direct connection. However, if when he is testing in his home with the computer and PMC-8 in close proximity, the signal strength is not comparable to what I get, I suspect a problem with the PMC-8 antenna. I had a potential problem, as the gold connector to which the antenna attaches was not fixed fast to the box, as delivered. This caused the gold connector to rotate with the antenna, twisting the wire connecting it to the circuit board and coiling it around the stem of the connector. I fixed the loose nut on the outside of the box, but had I not done so, it is possible that the internal wire would at some point have strangled the connector and broken its solder joint. If this had happened, leaving the wire coiled around the connector, it would still be feasible for the 2.4 GHz signal (wavelength c. 12.5 cm) to reach the antenna, though at a much lower level -- in the absence of competition from other signals, possibly still high enough to connect to the network, but in an unreliable fashion.

In a remote observing place I would expect the problems of competing signals to be much less acute than in my apartment. One day, when the clouds lift, I hope to verify this!

David


r_hoskin@...
 

David,

I tried WifiInfoView as well.  Very nice - helped me polish up the home network a bit.
I don't use the wifi on my PMC-8, but I did check its antenna connector and FWIW, that seems to be tight. 

I really do wonder if at least part of the gets-worse-at-remote site has to do with power management.  Brent said he was using a laptop, not a tablet.  A laptop at home will likely be running on the mains.  A laptop outside will be on battery and using a different power plan. 

As an example:

https://www.intel.com/content/www/us/en/support/articles/000005879/network-and-i-o/wireless-networking.html

My laptop wifi adapters are kept at maximum power on either power source. What would the default be on a Win10 laptop?  No idea, but something to wonder about...

- Bob
 


David Pickett
 

At 18:09 14-02-18, r_hoskin@... [ESPMC-Eight] wrote:

I really do wonder if at least part of the gets-worse-at-remote site has to do with power management. Brent said he was using a laptop, not a tablet. A laptop at home will likely be running on the mains. A laptop outside will be on battery and using a different power plan.

As an example:

https://www.intel.com/content/www/us/en/support/articles/000005879/network-and-i-o/wireless-networking.html

My laptop wifi adapters are kept at maximum power on either power source. What would the default be on a Win10 laptop? No idea, but something to wonder about...
I checked mine (way down there in the menus!) and it was Maximum for both too. I think I must have set it myself, so dont know what the default was.

But it's a good point and Brent might want to check it.

When I got my Win 10 laptop (Asus Zenbook) the battery lasted six or more hours. A year later it is down to less than four hours and I read that the batteries are only good for 300-500 recharges before they lose significant capacity. In 365 days I have probably charged it about 300 times already!

David


hubbell_jerry@...
 

Thanks David for your insight into this problem with the WiFi connectivity. Currently the firmware in the controller is set to increment the channel numbers between 1 and 10. The problem could very well be the antenna, and I have seen the problem with the connector coming loose with the user unaware that when he tries to tighten the antenna all he is doing is wrapping the cable internally. As far as Windows be a contributor, the Android version of the ExploreStars application seems to be much more robust in terms of connecting and staying connected to the PMC-Eight. So there could be something there also. So to summarize, here are the suspect causes for dropouts:

1.  Antenna connection
2. Windows platform
3. Power Supply to computer.

Thanks

Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.