Intermittent connection

NSILMike · 05-21-2019, 01:52 PM

I've recently upgraded from an antique samsung android tablet to the Kindle Fire 7. I installed the Google Play Store onto it so I can install and run my old Android Apps, including CC. The problem is that the wireless and content server connections are intermittent- works fine one time then fails ("Could not find Calibre") the next. Rebooting makes no noticeable difference. Also, it so far never fails to connect by USB. Any ideas on how to correct this?

Update: I have now set a fixed IP address and port (works) and will see if this cures the problem.

theducks · 05-21-2019, 02:45 PM

Sometimes devices switch WiFi bands. If your router has both, make sure you device only reconnects to the same every time (you can disconnect) the un-desirable one in WiFi settings on your device

NSILMike · 05-21-2019, 03:03 PM

Yes, my Asus router is dual band, but both are active and the Kindle Fire only supports 2.4GHz so I doubt it is a wifi band problem, plus the laptop is set to connect only to one band.

Update: setting the fixed port doesn't work. still intermittent connections.

chaley · 05-21-2019, 04:44 PM

Is the problem location or time sensitive? By "location" I mean that the failures tend to occur when you are in some particular room. By "time" I mean time of day.

I ask because WiFi is extremely sensitive to interference, especially the 2.4GHz band. For example, microwave ovens and DECT telephones run on that band. It could also be related to a neighbor's WiFi. Finally, it could be related to other downloads happening on the home net at the moment you connect. The CC "are you there, calibre?" broadcast messages will be thrown away by the router if it is very busy.

One experiment: change which 2.4GHz WiFi channel your router is using. Some routers have a channel scan feature that searches for the least congested channel.

Another experiment: if it fails, move to very close to the router and try again.

NSILMike · 05-21-2019, 04:57 PM

Thanks.
I haven't noticed it being time or location sensitive, but could not prove that. It sometimes fails and other times succeeds when it is about a foot from the router. I have also scanned for wifi channels that are low use. There are other wifi devices (chromecasts and LIFx smart bulbs) but they have been there for quite awhile and this problem is only about a week old.

chaley · 05-21-2019, 05:09 PM

Another random thought: last week I had a problem where nothing could connect to the 2.4GHz band of my WiFi repeater. After much gnashing of teeth I found that if the repeater was close to my USB 3 hub then it didn't work. Moving it some distance away (a couple of feet or so) fixed it.

Turns out that some USB 3 installations leak massive amounts of energy on the 2.4GHz band, effectively shutting down WiFi. This leakage can depend on how the hub is being used at the moment. For more info see this site. For a summary see this site.

I have seen the same problem with wireless keyboards. I cannot plug the little dongle into my USB 3 hub and have it work. I must use an extension cable and move the dongle a yard away (thereabouts) from the hub.

Any chance that you have moved equipment around in the last week?

NSILMike · 05-21-2019, 05:13 PM

No, nothing has changed. Laptop running CC is connected by cable and wifi (and is about 3 feet from the router) and has been forever. In this room, the only wifi enabled devices are the laptop, and the tablet (which doesn't seem to care if it is close or in another room.)

chaley · 05-22-2019, 06:10 AM

Well, I am at a loss. The fact that it works sometimes implies that the basic networking setup is correct, that CC can "see" the calibre machine, and that the firewall & A/V on the calibre machine are not blocking traffic. It isn't a protocol issue because both the content server and the wireless device work.

I don't know what would cause the intermittent problems other than the ones I mentioned above. Clearly *something* is blocking network traffic, probably the connection sequence. That can happen if something is interfering with the WiFi signal, the laptop wanders off into some very busy state such as doing a network backup, or the Fire does something similar such as syncing with Amazon.

You mention that the laptop is connected by both cable and wifi. That will result in the laptop having 2 IP addresses. It is possible that the Fire is trying to use both of them, which will not work. Calibre will also try to use both, which can lead to confusion about which to use when talking to the fire. Try disconnecting one or the other.

NSILMike · 05-22-2019, 08:34 AM

Thanks for trying! I am also at a loss... Nothing has recently changed but this issue came up only recently. I've also experimented with fixed IP address and automatic with wifi or direct cable connection or both and nothing seems to make a difference. I can only guess, but wouldn't be surprised if there is a recent glitch in the firmware of one of the wireless devices... but we shall see.

05-21-2019, 01:52 PM	#1
NSILMike Guru Posts: 735 Karma: 35936 Join Date: Apr 2011 Location: Shrewsury, MA Device: Lenovo Android Tablet	Intermittent connection I've recently upgraded from an antique samsung android tablet to the Kindle Fire 7. I installed the Google Play Store onto it so I can install and run my old Android Apps, including CC. The problem is that the wireless and content server connections are intermittent- works fine one time then fails ("Could not find Calibre") the next. Rebooting makes no noticeable difference. Also, it so far never fails to connect by USB. Any ideas on how to correct this? Update: I have now set a fixed IP address and port (works) and will see if this cures the problem. Last edited by NSILMike; 05-21-2019 at 02:22 PM.

05-21-2019, 03:03 PM	#3
NSILMike Guru Posts: 735 Karma: 35936 Join Date: Apr 2011 Location: Shrewsury, MA Device: Lenovo Android Tablet	Yes, my Asus router is dual band, but both are active and the Kindle Fire only supports 2.4GHz so I doubt it is a wifi band problem, plus the laptop is set to connect only to one band. Update: setting the fixed port doesn't work. still intermittent connections. Last edited by NSILMike; 05-21-2019 at 03:33 PM.

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05-21-2019, 02:45 PM	#2
theducks Well trained by Cats Posts: 29,946 Karma: 55705602 Join Date: Aug 2009 Location: The Central Coast of California Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A	Sometimes devices switch WiFi bands. If your router has both, make sure you device only reconnects to the same every time (you can disconnect) the un-desirable one in WiFi settings on your device

05-21-2019, 04:44 PM	#4
chaley Grand Sorcerer Posts: 11,774 Karma: 7029857 Join Date: Jan 2010 Location: Notts, England Device: Kobo Libra 2	Is the problem location or time sensitive? By "location" I mean that the failures tend to occur when you are in some particular room. By "time" I mean time of day. I ask because WiFi is extremely sensitive to interference, especially the 2.4GHz band. For example, microwave ovens and DECT telephones run on that band. It could also be related to a neighbor's WiFi. Finally, it could be related to other downloads happening on the home net at the moment you connect. The CC "are you there, calibre?" broadcast messages will be thrown away by the router if it is very busy. One experiment: change which 2.4GHz WiFi channel your router is using. Some routers have a channel scan feature that searches for the least congested channel. Another experiment: if it fails, move to very close to the router and try again.

05-21-2019, 04:57 PM	#5
NSILMike Guru Posts: 735 Karma: 35936 Join Date: Apr 2011 Location: Shrewsury, MA Device: Lenovo Android Tablet	Thanks. I haven't noticed it being time or location sensitive, but could not prove that. It sometimes fails and other times succeeds when it is about a foot from the router. I have also scanned for wifi channels that are low use. There are other wifi devices (chromecasts and LIFx smart bulbs) but they have been there for quite awhile and this problem is only about a week old.

05-21-2019, 05:09 PM	#6
chaley Grand Sorcerer Posts: 11,774 Karma: 7029857 Join Date: Jan 2010 Location: Notts, England Device: Kobo Libra 2	Another random thought: last week I had a problem where nothing could connect to the 2.4GHz band of my WiFi repeater. After much gnashing of teeth I found that if the repeater was close to my USB 3 hub then it didn't work. Moving it some distance away (a couple of feet or so) fixed it. Turns out that some USB 3 installations leak massive amounts of energy on the 2.4GHz band, effectively shutting down WiFi. This leakage can depend on how the hub is being used at the moment. For more info see this site. For a summary see this site. I have seen the same problem with wireless keyboards. I cannot plug the little dongle into my USB 3 hub and have it work. I must use an extension cable and move the dongle a yard away (thereabouts) from the hub. Any chance that you have moved equipment around in the last week?

05-21-2019, 05:13 PM	#7
NSILMike Guru Posts: 735 Karma: 35936 Join Date: Apr 2011 Location: Shrewsury, MA Device: Lenovo Android Tablet	No, nothing has changed. Laptop running CC is connected by cable and wifi (and is about 3 feet from the router) and has been forever. In this room, the only wifi enabled devices are the laptop, and the tablet (which doesn't seem to care if it is close or in another room.)

05-22-2019, 06:10 AM	#8
chaley Grand Sorcerer Posts: 11,774 Karma: 7029857 Join Date: Jan 2010 Location: Notts, England Device: Kobo Libra 2	Well, I am at a loss. The fact that it works sometimes implies that the basic networking setup is correct, that CC can "see" the calibre machine, and that the firewall & A/V on the calibre machine are not blocking traffic. It isn't a protocol issue because both the content server and the wireless device work. I don't know what would cause the intermittent problems other than the ones I mentioned above. Clearly something is blocking network traffic, probably the connection sequence. That can happen if something is interfering with the WiFi signal, the laptop wanders off into some very busy state such as doing a network backup, or the Fire does something similar such as syncing with Amazon. You mention that the laptop is connected by both cable and wifi. That will result in the laptop having 2 IP addresses. It is possible that the Fire is trying to use both of them, which will not work. Calibre will also try to use both, which can lead to confusion about which to use when talking to the fire. Try disconnecting one or the other.

05-22-2019, 08:34 AM	#9
NSILMike Guru Posts: 735 Karma: 35936 Join Date: Apr 2011 Location: Shrewsury, MA Device: Lenovo Android Tablet	Thanks for trying! I am also at a loss... Nothing has recently changed but this issue came up only recently. I've also experimented with fixed IP address and automatic with wifi or direct cable connection or both and nothing seems to make a difference. I can only guess, but wouldn't be surprised if there is a recent glitch in the firmware of one of the wireless devices... but we shall see.

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