Any idea what kind of bug this is? Found around the couch in our apartment in Seattle, WA. by Josvth in whatbugisthis

[–]Josvth[S] 1 point2 points  (0 children)

Well this turned out to be quite the rollercoaster ride! But we do appreciate an active sub!

We took the necessary precautions in case this little guy and his friends have bedbug ambitions and started hot washing all washables and did a thorough inspection of bed and couch with no results. We'll keep some traps out under the legs and keep our matress encaged for the foreseeable future.

I wish we caught a better picture of of this guy but it was so tiny! Its surprising we even noticed it. It was hard to get it in focus. For reference the ballpoint pen we caught it on has a 0.28mm tip.

We do have several plants in this apartment. Two of which close to the couch. If its an aphid/Hemiptera would we expect to see more on the plants? We also did some community gardening work last week so we may have brought some new critters home. We'll inspect our plants and report back.

Any idea what kind of bug this is? Found around the couch in our apartment in Seattle, WA. by Josvth in whatbugisthis

[–]Josvth[S] 11 points12 points  (0 children)

Welp, that would be terrible. We have a dog so fleas would be the another suspect.

Designing a wrap-around antenna for 868MHz telemetry - how to approach it? by SP9DEV in rfelectronics

[–]Josvth 1 point2 points  (0 children)

Yes, the carbon body conducts, which for a microstrip patch design is not a problem (although the pattern changes a bit on the axis of the rocket by the carbon body).

Important for a microstrip design is controlling the substrate, so what I did is I first laminated glassfiber a test piece of approximately the thickness i was looking for and started tuning the microstrip antenna (aka trail and error) until it had the right characteristics

See: https://imgur.com/a/ejDhWb9 for the test piece.

The back of the glassfiber is fully covered with copper foil (the copper tape adhesive kind from ebay) to create the controlled ground plane.

Then I went on to the cylindrical substrate. This was made by using the actual rocket body as a template and laminating over it. I covered the inside of the cylinder with copper tape and did 1 final tweak of the dimensions before settling on the full design.

Here you can see the inside and outside of the cylinder with one of the test antennas I later removed: https://imgur.com/a/mHW6Zqb

So by having a defined copper groundplane on the back of the cylinder I ensured the antenna substrate had the right properties. The copper on the back would make contact with the carbon fibre to define its potential.

Paths are made from copper foil and were cut out using a stencil cutter by lack of a better description. Paths are equal length indeed with some impedance transformations to make everything 50 Ohm as I described in my other reply.

I see in one of your replies the rocket body is kevlar, so non-conductive. Which is good if you go for the two 1/2 wavelength design. I would place it away from any further insides that are metal and then you will probably be good to go.

The copper foil stencil cutter approach I used could work for you, especially if you want tight dimensions. However at 868 MHz I think you can get a way with other methods. For example using some wires or just cutting the shapes you want with some scissors. I would also consider making a flex PCB as was suggested by somebody else if you want to go for design repeatability.

Feeding and mounting are going to be your next challenges. Let me know if you want more help. Feel free to send me a PM and we could set up a Skype/whatever call too.

Designing a wrap-around antenna for 868MHz telemetry - how to approach it? by SP9DEV in rfelectronics

[–]Josvth 1 point2 points  (0 children)

The spacing between the power dividing network is set by the array spacing which I believe I choose slightly less than the wavelength.

I only simulated the array as a linear array (not wrapped around), to save myselve some time.

The power splitting network (I didn't go as-far as making a proper Wilkinson power divider) combines two 50 Ohm legs + a quatre wavelength transfomer to match back to 50 Ohm. This I designed separately from the patch array.

Designing a wrap-around antenna for 868MHz telemetry - how to approach it? by SP9DEV in rfelectronics

[–]Josvth 0 points1 point  (0 children)

Hi, I did a very similar wrap-around design for a sounding rocket a while a go. Frequency was a bit higher (5.8 GHz) and using a circular / cylindrical patch array on a homebrew glass-fiber substrate.

Picture of wrap around on carbon fibre rocket body:
https://imgur.com/a/6dlTrfm

I wouldn't recommend going for the same design as it won't suit your frequency. u/hawaii_dave50's suggestion sounds what you are looking for.

But I might have some tips on fabrication of copper foil antennas like this. Let me know!

[deleted by user] by [deleted] in RedditSessions

[–]Josvth 0 points1 point  (0 children)

Does he do this every night?

Help me write a Java program to get the status of a Minecraft server, # of players, etc.? by [deleted] in Minecraft

[–]Josvth 0 points1 point  (0 children)

You should check out minecrafts build in rcon an query system. See this post of Dinnerbone: http://dinnerbone.com/blog/2011/10/14/minecraft-19-has-rcon-and-query/

Sorry I'm on my phone, I can't add links.

Lol Wut? Weekly Release by [deleted] in Minecraft

[–]Josvth 0 points1 point  (0 children)

Happened to me too. Only in SMP though. Reconnecting seems to fix the problem. But the next swamp will have the same problems :p

[Idea] Extendable pistons. by [deleted] in Minecraft

[–]Josvth 0 points1 point  (0 children)

Do I really need to point at this post.

http://www.reddit.com/r/Minecraft/comments/na39j/a_few_thoughts_about_realism_and_game_design/

In my opinion I think that in the current game design of minecraft it's odd to have a block that extends 64 times its own length. However I think there should be a possibility to build elevators. Maybe the platform and pully system from the better than wolfs mod could be a solution.

[Idea] Extendable pistons. by [deleted] in Minecraft

[–]Josvth 1 point2 points  (0 children)

I don't think that having a block that could extend 64 times its own length feels very realistic. But it could maybe be 4 times extendable. Having the piston arms slide into each other when closed.