[HamWAN PSDR] The 3rd time is not charmed [was: 8dB drop/rise!]
Dean Gibson AE7Q
hamwan.stuff at ae7q.com
Mon Jul 21 13:43:10 PDT 2014
Well, now that the radio is inoperative, I can't look at the /interface
wireless monitor output, but the graph comes from "The Dude". You're
probably correct in implying that the graph shows effective speed.
I'm trying "NetInstall", with no luck so far.
On 2014-07-21 13:14, Bart Kus wrote:
> Are you sure that's graphing link speed? How did it dip below 6Mbit?
> (MHz y-axis label?) The modems cannot operate slower than that in
> only-n mode.
>
> --Bart
>
>
> On 07/21/2014 01:08 PM, Dean Gibson AE7Q wrote:
>> The displayed link speed was also dropping. See
>> http://www.ae7q.com/misc/media/5.9GHz/2014-07-xx_Data.png
>>
>> On 2014-07-21 11:24, Bart Kus wrote:
>>> Have you looked at the possibility that your modem is negotiating a
>>> higher link speed over time and that's the cause for the gradual
>>> signal level loss? When you reboot these things and they aren't
>>> pressed to move data, they opt for the slowest (and highest power)
>>> modulation. As data comes in for them to move, if they build up
>>> queues, they try higher order modulations, which make use of
>>> amplitude modulation, and reduce the average power level.
>>>
>>> It is possible to instruct the modem to only support a subset of
>>> speeds. For example, the slowest speed only (6Mbit):
>>>
>>> [eo at AE7SJ/Monroe-Paine] /interface wireless> set 0 supported-rates-a/g=
>>> 12Mbps 18Mbps 24Mbps 36Mbps 48Mbps 54Mbps 6Mbps 9Mbps
>>>
>>> I don't think upgrading or downgrading firmware has anything to do
>>> with RSSI readings as they're read directly from the Atheros chip
>>> and not computed in firmware.
>>>
>>> The real test of the health of your connection would be if it
>>> consistently supports the same ballpark speed range (bits/sec
>>> actually moved) or if it is indeed dropping due to this 8dB RSSI
>>> delta you're seeing. If the modem finds itself having too many
>>> communication errors because it chose a modulation that is too fast,
>>> it'll lower its negotiated speed.
>>>
>>> --Bart
>>>
>>>
>>> On 7/21/2014 10:28 AM, Dean Gibson AE7Q wrote:
>>>> OK, over the last three weeks both the TX and RX signal levels have
>>>> dropped 8dB; see:
>>>>
>>>> http://www.ae7q.com/misc/media/5.9GHz/2014-07-xx_RX.png
>>>>
>>>> While this could be due to vegetation, the drop (somewhat gradual
>>>> this time) looks suspiciously like the previous two drops of 8dB
>>>> (see prior messages below). On Friday I noticed that MicroTik had
>>>> a new firmware release, v6.17, and I upgraded to that. That fixed
>>>> an NTP bug introduced in v6.14 but made no difference in dBm
>>>> levels, so Sunday evening I downgraded to v6.13. That
>>>> downgrade/reboot was successful, but also made no difference. So,
>>>> I did a second reboot in preparation for upgrading back to v6.17
>>>> (using the same scenario as below).
>>>>
>>>> This time, however, "presto!" (the results below) does not quite
>>>> apply. The 5SHPn shows a power-on LED, and when connected to a
>>>> switch, shows an electrical network LED. However, *the 5SHPn is
>>>> inaccessible via Ethernet* (using Winbox to access via both by last
>>>> IP address, and by MAC address). PINGs fail; there is no
>>>> corresponding entry in the ARP table. I can hold in the reset
>>>> button while power-cycling the 5SHPn, and I get the flashing power
>>>> LED indicating a "reset configuration" is happening, but to no
>>>> avail: Winbox is unable to connect to the 5SHPn.
>>>>
>>>> *This is the third time I've had this 8dB drop*, and the second
>>>> time I've had to go to the roof to reset the radio. So, I've
>>>> removed the antenna from the roof. So, unless someone has a bright
>>>> idea, the 5SHPn and the 31dBi dish antenna are available for $120
>>>> total. I'd like to sell them as a unit, because I've got a really
>>>> nice (but easily removable) taped seal of the antenna/radio
>>>> connection. If you can't get the radio to work, you're only out $20.
>>>>
>>>> -- Dean
>>>> 425-338-4276 (home)
>>>> 425-359-4276 (cell)
>>>>
>>>> On 2014-06-13 18:29, Dean Gibson AE7Q wrote:
>>>>> Going back to v6.13 didn't improve anything, but it did seem to
>>>>> get rid of the occasional variations in voltage (from 13.5v down
>>>>> to 12.8v) that SNMP was reporting to "The Dude" software. So,
>>>>> after letting v6.13 run for couple hours with no improvement, I
>>>>> reinstalled v6.15.
>>>>>
>>>>> Presto! Instant dBm improvement back to my normally observed
>>>>> values. Here are links to SNMP graphs of the drop @9:30am, and
>>>>> the rise at 17:48pm. Of course, you can also see this in Nigel's
>>>>> Cacti reporting, albeit with less horizontal (time) resolution.
>>>>>
>>>>> http://www.ae7q.com/misc/media/5.9GHz/2014-06-13_0940.png
>>>>> http://www.ae7q.com/misc/media/5.9GHz/2014-06-13_1740.png
>>>>>
>>>>> Note that the reported sudden dBm "rise" to -60dBm (the upper
>>>>> limit I've imposed to keep the graph scale reasonable) on two
>>>>> occasions in the second graph, is when I upgraded and then
>>>>> reconfigured the radio (from a cut-&-paste script), and should be
>>>>> ignored.
>>>>>
>>>>> Note that a very similar scenario occurred several months ago,
>>>>> when I upgraded from v6.10 to v6.12.
>>>>>
>>>>> Of course, today is Friday the 13th. Maybe Jason is responsible.
>>>>>
>>>>> -- Dean
>>>>>
>>>>> On 2014-06-13 12:28, Dean Gibson AE7Q wrote:
>>>>>>
>>>>>> On 2014-06-13 12:13, Cory (NQ1E) wrote:
>>>>>>> Did it rain on those trees you're pointing at around then? :)
>>>>>>>
>>>>>>> On Fri, Jun 13, 2014 at 12:12 PM, Dean Gibson AE7Q
>>>>>>> <hamwan at ae7q.com <mailto:hamwan at ae7q.com>> wrote:
>>>>>>>
>>>>>>> This morning (well after the update to v6.15 last night)
>>>>>>> just after 9:30am, I saw a 8dB drop in both TX and RX signal
>>>>>>> levels, which persist at this time. I did a "reset
>>>>>>> configuration", which did not solve the problem.
>>>>>>>
>>>>>>> Did anyone do a change at Paine sector 2 around 9:30am?
>>>>>>>
>>>>>>
>>>>>> It's been raining gently all morning. Last night it rained a bit
>>>>>> harder, and I saw no significant or unusual variation. I'm going
>>>>>> back to v6.13 to see if that changes anything.
>>>>>>
>>>>>> The drop was very sudden. I have that antenna connection very
>>>>>> well sealed, I thought, and the Ethernet cable runs uphill to get
>>>>>> into the eaves. I did a cursory visual check of that this morning.
>>>>>
>>>>
>>>> On 2014-05-04 13:00, Dean Gibson AE7Q wrote:
>>>>> OK, everything is back working, and I have my dBm back!!
>>>>>
>>>>> Not a comedy of errors, but two factors intertwined to create this
>>>>> problem:
>>>>>
>>>>> 1. Since configuring the radio after a configuration reset
>>>>> requires the use of WinBox (until you get IP addresses set
>>>>> up), I moved the network connection from the radio to its
>>>>> normal router on the DMZ, and connected it to a router on my
>>>>> LAN via an extension Ethernet cable and a "dual-RJ-45-jack
>>>>> adapter". The port light on the router associated with the
>>>>> radio connection was off. This morning when I went to
>>>>> disconnect the cables, I saw the port light on the router
>>>>> flash momentarily. Junked the dual-RJ-45 adapter and used
>>>>> another one (I had previously tried a different cable), and I
>>>>> had WinBox access to the radio! Everything worked except for
>>>>> the LEDs ...
>>>>> 2. *After much more screwing around*, I found out that for
>>>>> version 6.12,*the LEDs are not configured by default* !!!
>>>>> Remember, I had done a "reset-configuration" ...
>>>>>
>>>>>
>>>>> So, for others that update to v6.12, here are the relevant lines
>>>>> in the setup:
>>>>>
>>>>> */system leds add type=interface-status interface=ether1-local
>>>>> leds=user-led
>>>>> /system leds add type=wireless-signal-strength
>>>>> interface=wlan1-gateway leds=led1,led2,led3,led4,led5*
>>>>>
>>>>> Now that I know I can configure the LEDs with other options, I'll
>>>>> try some.
>>>>>
>>>>> I have no clue as to why my dBm dropped, and why I now have my
>>>>> prior values back ...
>>>>>
>>>>> -- Dean
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: PSDR [mailto:psdr-bounces at hamwan.org
>>>>> <mailto:psdr-bounces at hamwan.org>] On Behalf Of Dean Gibson AE7Q
>>>>> Sent: Sunday, May 4, 2014 1:44 AM
>>>>> To: Puget Sound Data Ring
>>>>> Subject: Re: [HamWAN PSDR] Metal 5SHPn firmware 6.12 is
>>>>> current (addendum)
>>>>>
>>>>> Well, this did not end well. ... I decided to reset the
>>>>> configuration (using the command line) ... it appears to have
>>>>> "bricked" the radio.
>>>>>
>>>>> It draws about 160ma (about the value from a week ago, when I
>>>>> first measured it). There is no light on the side of the
>>>>> unit, and the Ethernet port is dead.
>>>>>
>>>>>
>>>>
>>>>
>>>>
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>>
>>
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