[HamWAN PSDR] The 3rd time is not charmed [was: 8dB drop/rise!]
Dean Gibson AE7Q
hamwan.stuff at ae7q.com
Mon Jul 21 13:08:57 PDT 2014
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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