[chbot] Planning for the next few weeks - SDR Experts?

[Mark Atherton]

Some parameters please
- max and min limit of carrier frequency, or Fnom ± Ftolerance
- repetition rate of the 100ms bursts ?
- transmit power
- transmit antenna

Do you have a pendant in hand to take apart ?

So unmodulated carrier, and no ident modulation ?

- Mark



On 22/03/2020 12:44 PM, Trevor Wignall wrote:
> Hi all
> As a Wandersearch responder (i.e. someone who goes out with a 
> directional receiver and tries to locate the small transmitter 
> pendants worn by people who tend to go wandering e.g. dementia 
> patients), I am looking at using a Software Defined Radio (SDR) to 
> receive these signals. However as the signals are weak, I am looking 
> for ways of extracting the short transmitted pulses (around 100-200 
> milliseconds of unmodulated carrier) from the background noise using 
> narrow band filtering. The problem is that the exact transmitter 
> frequency is not known due to tolerances, temperature changes etc.
> If anyone familiar with SDRs would like a challenge to combat boredom, 
> any help would be appreciated.
> Trevor
>
> On Sun, Mar 22, 2020 at 11:28 AM Mark Atherton <markaren1 at xtra.co.nz 
> <mailto:markaren1 at xtra.co.nz>> wrote:
>
>     One more time, this go includes the Robotics group in the to: list :)
>
>
>     Greetings Robotters.
>
>
>     This is more of a brain-dump than anything too coherent; please
>     contribute ideas as required.
>
>     The next few weeks are going to be rather interesting to say the
>     least,
>     and while some of us relish the thought of time alone, others may be
>     concerned about boredom creeping in.
>
>     Spare time, does of course mean opportunity, and with a little
>     planning,
>     things can be done, plates can be spun, and progress can be made.
>
>     Things that come to mind include the following:
>
>     Develop. Something rattling around in your head for a while and needs
>     implementing, is it time to get out the soldering
>     iron/keyboard/angle-grinder and get going on it ?
>
>     Repair. Broken things tend to accumulate. Not sure how to repair it -
>     ask here, or find a specialist forum.
>
>     Clear out. Sinking in it ? Round it up, and chuck it out.
>
>     Document. Surrounded by lots of interesting complete projects, but
>     little published work ? Maybe it's time to open a hackaday
>     account, and
>     start reporting your progress and projects to the world ?
>
>     Learn. Stuff you are interested in ? Find a forum, an online
>     resource,
>     youtube - get stuck in. Not sure what the question is ? Ask here,
>     we may
>     know what you are trying to do and give some ideas about how to find
>     required resources.
>
>     Educate. Time to give back ? Maybe find a forum who could do with a
>     mentor. Contribute.
>
>     Stock up. Not sure how long the electronic component suppliers are
>     going
>     to be open for, so maybe it's time to pay a visit to Jaycar/South
>     Island
>     Components/Ecotech/Molten Media and load up with stuff while they are
>     open. They may have to close for a while, and an acute widget
>     shortage
>     can be frustrating.
>
>     Share. I hate that phrase, but in this context, you may have stuff
>     surplus which may be useful to others. Give to the other givers
>     first ?
>
>     Scrounge. If you have a specific project in mind (not just
>     stocking up)
>     put out a Request-For-Scrounge (RFS). You might be amazed what stuff
>     people have squirrelled away.
>
>     As usual, lurkers, and regulars alike, please speak up about
>     projects,
>     ideas etc. Please keep the subject line of messages updated to track
>     content.
>
>     Things will return to some kind of normal over the next few weeks,
>     but
>     busy hands, fingers and keyboards can alleviate the stress of change.
>
>     Comments, updates, and suggestions as usual are always welcome.
>
>     Keep safe.
>
>     -Mark
>
>     PS I have copied a few non-robot-group members who seem relevant
>     to this
>     topic. Please sign up to be included in any of our discussions via
>     kiwibots.org <http://kiwibots.org> or directly at
>     https://lists.ourshack.com/mailman/listinfo/chchrobotics As a
>     (nearly)
>     French person once said "I will say this only once"
>
>
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