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Author Topic: WIFI Problem  (Read 6244 times)
NT0A
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Posts: 97




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« on: August 18, 2012, 09:54:09 AM »

Perhaps some of you recall my saga with eliminating externally generated RFI from the shack about a year ago. I was successful in killing the spurious RF radiation from the cable connecting the Time-Warner cable modem from my WIFI, but I have struggled with a WIFI problem for months without much luck. As I sit here at my desk three feet from the WIFI router, the download speed is 22.55 Mbps. In the living room with the laptop is slips to 19 to 20 Mbps, and in the bedroom 15 to 18 Mbps. Downstairs in the ham shack, however, it drops to less than 0.5 Mbps.

Obviously the simple solution would be to add a second router or extender in the basement and hard wire it to the source in the computer room. Unfortunately, as previously reported, the CAT5 and CAT6 cables put out tons of RF that ruins HF radio reception on the ham bands. I had to reduce the effective length of a 25 foot CAT6 cable to two feet by wrapping it around four toroids. That is the only cable in the network and it goes from the cable modem to the WIFI router.

I've installed repeaters or extenders, but that does not seem to help very much. I am wide open to any and all suggestions except moving the ham shack yet again.
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K3AN
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Posts: 787




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« Reply #1 on: August 20, 2012, 11:54:45 AM »

Is there sheet metal ductwork in the basement ceiling between the router on the main floor and the laptop's location in the basement? Did you try turning the router and/or rotating its antenna to a horizontal position to see if that improves the speed? If you move the laptop to some other place in the basement does the speed improve? How about trying to move the router?

Our Netgear router on the first floor has no trouble sending to and receiving from the laptop in my basement hamshack.
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AA4PB
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« Reply #2 on: August 20, 2012, 12:38:18 PM »

I wonder if you might have some RFI on the wireless frequency (or even neighbors using the same frequency) that may be slowing things down as you move farther from the wireless router. My LinkSys wireless has good coverage of the entire house, upstairs and downstairs, and out on the deck.
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W8JX
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Posts: 6089




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« Reply #3 on: August 20, 2012, 01:12:21 PM »

The problem with WiFi is that there is very little actual room on 2.4 ghz B/G/N band. Faster speeds span more space. For starters download a program called "Inssider" and it will show you if there is other nodes interfering with you. Also a microwave oven can wipe 2.4ghz WiFi out sometimes when running. Some wireless routers have longer range too. I have had good luck with Netgear WNDR 3400 routers in home and small office setups. They are dual band too (2.4 and 5ghz 802.11A band) and have good range. They are about 80 bucks at Walmart and well worth it. As far as a secondary wireless node in house if you go that route you want to get a AP (Access Point) not a repeater. A AP is hard wired to router and operates with its out ID and channel. I have long used them here to extend range.
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All posted wireless using Win 8.1 RT, a Android tablet using 4G/LTE/WiFi or Sprint Note 3.
STAYVERTICAL
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Posts: 875




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« Reply #4 on: August 23, 2012, 12:12:32 AM »

I know it is pretty obvious, but could the WIFI router you are using have an external antenna which has a null below it.
If you move the WIFI router around say put it on its side, does the performance pick up downstairs?

Just a thought.

73 - Rob
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NT0A
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Posts: 97




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« Reply #5 on: August 23, 2012, 06:43:37 AM »

Don't you just love it when a problem solves itself, but you don't have a clue how or why? Only thing I did was manually switch from channel 1 to a higher channel (10) on the router. Whether that solution works for all times remains to be seen.

Ironically, nothing happened for the better until the entire Time-Warner Cable for my area went tits up. Once it was fixed, the Internet speed in the shack shot up. Why it didn't happen as soon as I made the channel change is anyone's guess.

Anyone want to guess? I have reserved the following answers for myself:

    1. Happenstance.

    2. Coincidence.

    3. Just because.

    4. Blind assed luck.

73s es tnx for the help de Bob NT0A
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AA4PB
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« Reply #6 on: August 23, 2012, 06:54:39 AM »

I notice that from time to time my cable speed will slow way down and stay until I reboot the cable modem. I expect that the cable signal gets interrupted during maintenance and it doesn't always sync back up correctly. A reboot always fixes it (so far).

Maybe there was something else on channel 1. Interferrence will cause data errors that can cause packets to be retransmitted multiple times which in turn slows down the throughput.

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W8JX
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« Reply #7 on: August 23, 2012, 08:14:40 AM »

Maybe there was something else on channel 1. Interferrence will cause data errors that can cause packets to be retransmitted multiple times which in turn slows down the throughput.

There is no channel one persay any more. Back in days of 11Mbit max "b" there was 11 channels but to get more speed with G then N they have to span several channels. Microwave ovens and some cordless phone reside on the lower end of 2.4ghz WiFi spectrum so moving to upper end can help. 
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All posted wireless using Win 8.1 RT, a Android tablet using 4G/LTE/WiFi or Sprint Note 3.
NT0A
Member

Posts: 97




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« Reply #8 on: August 23, 2012, 08:25:41 AM »

Maybe there was something else on channel 1.

Great idea, but nothing showed up on a scan around 2.4GHz. Doesn't mean there wasn't something there when I was not scanning, however. Franky, I suspect that some sort of interference on the low end of the band was the root cause.

Now, inSSIDer.exe shows that the signal spans channels 4 through 12 rather than 1 through 9.

FWIW, Here's another reason that I have reserved:

    5. Shit happens!
« Last Edit: August 23, 2012, 08:28:51 AM by NT0A » Logged
K1CJS
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Posts: 6045




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« Reply #9 on: August 24, 2012, 04:05:24 AM »

Even though nothing showed up on a scan, there was interference.  Could have also been a harmonic just strong enough to slightly scramble the signal.  Changing the 'channel' cleared the interference.
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W8JX
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Posts: 6089




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« Reply #10 on: August 24, 2012, 05:00:14 AM »

Even though nothing showed up on a scan, there was interference.  Could have also been a harmonic just strong enough to slightly scramble the signal.  Changing the 'channel' cleared the interference.

Inssider will only show WiFi signals and not interference like cordless phones and other wireless devices in the spectrum as well as microwave ovens.
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All posted wireless using Win 8.1 RT, a Android tablet using 4G/LTE/WiFi or Sprint Note 3.
NT0A
Member

Posts: 97




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« Reply #11 on: August 24, 2012, 05:47:23 AM »

Inssider will only show WiFi signals and not interference like cordless phones and other wireless devices in the spectrum as well as microwave ovens.

True.
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KB2WIG
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Posts: 119




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« Reply #12 on: August 24, 2012, 08:51:37 AM »

" I notice that from time to time my cable speed will slow way down and stay until I reboot the cable modem. "

My system does that also... But the problem isn't in the cable modem. I run a Netgear router that I need to reboot. After I reboot, the system is back to normal.


klc
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KA1VF
Member

Posts: 35




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« Reply #13 on: September 05, 2012, 06:54:15 PM »

   I've had Verizon's Westell model# 7500 DSL wireless router installed for several years downstairs
next to my desktop, and my laptop installed for several years upstairs on my radio desk. The physical
location of the downstairs router is fixed and the upstairs laptop is fixed, and their 2.4 Ghz signal paths
are approximately 12 feet line of sight point-to-point.

    Questions: Why does the router signal strength change (good, very good, excellent)?
                    Why does a good signal = 36.0 Mbps and an excellent signal = 54.0 Mbps?
       


     
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W8JX
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Posts: 6089




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« Reply #14 on: September 06, 2012, 08:00:25 AM »

 
     Questions: Why does the router signal strength change (good, very good, excellent)?
                    Why does a good signal = 36.0 Mbps and an excellent signal = 54.0 Mbps?


Because of a function known as "auto retrain for best rate" it will hunt around in strength and speed under less than perfect conditions. It is based on CRC error rate and signal level. Think of a WiFi signal as a beam of light in that as you focus beam tightly (narrower spectrum for slower WiFi speeds) and as you broaden it,  it covers more area but is dimmer in those areas (when WiFi is higher speed it uses same power over a wider spectrum)

They way around this is to manually set speed of access point. I set mine to 18Mbps which is more than enough for any broad band connection at home and you will get much better performance and consistent signal and disable auto retrain. No loss of data flow during retrain either because it is disabled.
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All posted wireless using Win 8.1 RT, a Android tablet using 4G/LTE/WiFi or Sprint Note 3.
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