[aprssig] weather station mess

Sat Feb 15 13:24:08 EST 2014

Jim,
  A few thoughts of the top...
 - Off hand, I'd say an uplink that has as many commands as possible is best.  Don't discount a 220, 6m or 10M  command uplink frequency, perhaps from another location within range.  

- With a two way command channel, you may also be able to monitor other things that can easily be downlinked on the command channel. 
- There are solid state relays.
- As a brute-force backup for this one problem, a rapid-packet elininator can be a timer that independantly (via a completely separate relay) removes power to the transmitter for a time just shorter than the 'normal' command.

Cheers, Steve, K9DCI

________________________________
 From: James Clayton <James.Clayton at riverbed.com>
To: "aprssig (aprssig at tapr.org)" <aprssig at tapr.org> 
Sent: Friday, February 14, 2014 2:52 PM
Subject: [aprssig]  weather station mess

Greetings all:

My mountaintop system did go sideways and blast everyone.  My apologies to MJ Inabnit (KE6SLS) and everyone else on the Northcoast affected by this malfunction.  My thanks to Scott (N1VG)  for reaching out to me, and helping with troubleshooting.

I updated my email address on qrz.com as well.

Being out of town I was able to send a friend up the hill and he unplugged the system from the solar power system it was supposed to be monitoring.  It will stay off-line until I we get to root cause, and I come up with a method to remotely disable it, giving access to several local hams in case I am traveling.

The tracker is on a mountaintop, around 2000 foot in altitude, with limited winter access, 24 volt solar power with batteries buried in a steel box to survive the cold.  No cell service, no utility power, no wireline telephone.  

As for the cause I think Scott has the right idea: I have two mechanical relays triggered by the Tracker, that drive two 100 watt dc to dc power supplies (24VDC nominal to 13.1VDC), and power up the radio every thirty minutes to send one burst and go to sleep.   I didn't put a snubber in the circuit and Scott suggested the field collapse on the relays was hitting the tracker and rebooting it.  When I retrieve the tracker I will send it to Scott for an autopsy to confirm.  Weird thing was the system has run fine since Christmas, so I stopped checking it 10 times a day as when I started.

Based on signal reports I got from MJ (KE6SLS), I am thinking of lowering the power output of the Alinco DR-135 so I don't need the mechanical relays.  My intent was to make the system more redundant but the additional complexity bit me instead.

Thinking this over I have decided to follow the best practices of my day job in technology, and come up with some sort of out-of-band management method to kill this thing regardless of what the failure mode is.  My current thinking goes like this:  Grab one of my old power saving 2M handhelds and tune it to a packet frequency (NOT 144.390), mate it to another tracker, and using the Argent trackers ability to accept remote commands,  have this second combo listen, always on, for aprs packets that will bring the built in power control either up or down (depending on if I can come up with a latching relay or how that goes-I am thinking a relay normally closed, then energized to open the circuit).  This way regardless of the problem with the primary system, I always have a listener on a quiet channel that will pull the plug if instructed to do so.  The site has several poles on it with buried conduit between them, so I plan to put this second unit in a
 box 30 feet away from the primary a
prs unit to reduce rfi concerns.

Lots of details to work out yet, but any comments or suggestions on this line of thinking?

-Jim
N5ZEF

....................................................................................................................................................
James has someone going out there today to shut it down.  My best guess is that inductive kickback from the two relays he's using to power the radio is causing a power transient in the tracker and it's rebooting every time it shuts off the radio.

Scott
N1VG

On 2/9/2014 9:20 PM, MJ Inabnit wrote:
>
> Thanks Scott.  you are right on the rig.  Glad you had his email 
> address.  I really wish guys would update their qrz pages--it's the 
> global contact place for us!  Anyway, the station started spewing 
> again, but again, has stopped.
>
> Thanks for your help!
>
> 73
> j
>
> On 02/09/2014 08:06 PM, Scott Miller wrote:
>> I already found him in my customer records (it appears to be a
>> Tracker3) and emailed him about the problem and offered some commands 
>> that should shut it down, assuming it's set up for remote access and 
>> isn't transmitting so fast that it can't hear.
>>
>> Scott
>> N1VG
>>
>> On 2/9/2014 7:24 PM, Jim Duncan wrote:
>>> QRZ is you friend...
>>>
>>> N5ZEF
>>> JAMES P CLAYTON
>>> 305 N MURPHY AVENUE
>>> SUNNYVALE, CA 94085
>>>
>>> Tried a Directory Assistance call, sorry no listed number by name or 
>>> that particular address.
>>>
>>> 73 de Jim, KU0G
>>>

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