🎓 Doc Freemo 🇳🇱 @freemo@qoto.org

Cleaned up my Directional Coupler project. Labeled the ports and even added the electrical characteristics at different frequencies on the bottom. I then added a coat of lacquer resin to seal in that beautiful copper color (which otherwise would go brown as it oxidized).

The final result has a sort of beauty to it.

#RF #EE #Electronics #Engineering #Science #ElectricalEngineering #RFEngineering #HAM #HamRadio

If anyone is curious here are the characteristics of the Directional Coupler I just posted. The top line is the dBm on the forward port and the bottom line is the dBm on the REFL port for a 0dBm input signal. The markers for the common radio bands.

#RF #EE #Electronics #Engineering #Science #ElectricalEngineering #RFEngineering #HAM #HamRadio

Woot, just tested the Insertion Loss on the directional Coupler I built. It has an amazing -0.05dB IL on most frequencies except 50MHz where it is still only -0.15dB!

#RF #EE #Electronics #Engineering #Science #ElectricalEngineering #RFEngineering #HAM #HamRadio

I finally had the nerve to seal her up. Next I am going to clean up the outside and put a coat of laquer on her before she begins to get a patina.

#RF #EE #Electronics #Engineering #Science #ElectricalEngineering #RFEngineering #HAM #HamRadio

Started the final draft of the directional Coupler. Building in extra levels of shielding and a 20:1 winding ratio. I'm stoked to finally have the design locked down

#RF #EE #Electronics #Engineering #Science #ElectricalEngineering #RFEngineering #HAM #HamRadio

Over the past few days I built 5 different Directional couplers. Each one uses either a new design even tierly or a new winding ratio. After all the testing I've finally figured out the ideal design for the frequency range I'm targeting. Time to build the final prototype.

#RF #EE #Electronics #Engineering #Science #ElectricalEngineering #RFEngineering #HAM #HamRadio

It took me 3 hours but I rolled two perfect 126 turn Toroid inductors. These will be two halves of the two transformers in a Tandem Match Circuit (Directional Coupler). Should have infinitesimal insertion loss

#RF #EE #Electronics #Engineering #Science #ElectricalEngineering #RFEngineering #HAM #HamRadio

Decided to build another tandem match circuit based directional Coupler. This time I used a 21:1 winding ratio instead of the last one at 8:1.

It seems to have reduced unwanted coupling at lower frequencies. But more important it decreased insertion loss from about 1.15dB to only 0.03dB at 2 MHz and 0.4dB around 50MHz.

I think I prefer this particular winding ratio for my design.

#RF #EE #Electronics #Engineering #Science #ElectricalEngineering #RFEngineering #HAM #HamRadio

So my Directional Coupler performed fairly well. Here is the output from my spectrum analyzer. Basically one trace is for the forward port when the antenna is matched, the other is when the antenna is an open circuit. Then the other two traces are the same condition on the reflected port.

As you can see all the powers show a nice flat -20db coupling. Only exception is the one cyan trace that shows the reflected port when the antenna is matched. Since there are no reflections as expected the response is much less. It is also not linear which is to be expected.

Pretty similar results to my last attempt. Though going with fewer windings this time (8 instead of 12) seems to have results in a slight stronger coupling (-20 dBM rather than the -23 dBM I got before).

All in all I'd say its a success.

#RF #EE #Electronics #Engineering #Science #ElectricalEngineering #RFEngineering #HAM #HamRadio

Woot! Just finished my high power directional Coupler. She works perfectly. A day well spent.

#RF #EE #Electronics #Engineering #Science #ElectricalEngineering #RFEngineering #HAM #HamRadio

A picture of an early prototype for my ROES SWR meter and VNC. I later had to completely redesign the hardware for version 1.0, but the UI is still pretty similar.

This week I hope to add a frequency counter to the design and work towards a v2.

PS: See my pinned post to see v1 in action along with the analog board. The post also includes the v1 Schematic

#EE #Electronics #Ham #HamRadio #RF #SCience #Engineering #ElectricalEngineering #ROES #SWR

Interesting fact of the day: if you put butter on an ant he, along with every other ant in the colony, will think he is dead. He will either walk over to the ant graveyard himself or be carried there by another ant. The ant will usually stay there until the butter wears off.

The reason for this is that butter is 35% Oleic Acid. This is the Fatty Acid responsible for triggering this response.

#InterestingFactOfTheDay #IFOTD #Science #biology

Epic read explaining the basic math behind #QuantumMechanics

#science

https://uwaterloo.ca/institute-for-quantum-computing/sites/ca.institute-for-quantum-computing/files/uploads/files/mathematics_qm_v21.pdf

"To help some of the newcomers make connections: name 5-7 things that interest you but aren't in your profile, as tags so they are searchable. Then boost this post or repeat its instructions so others know to do the same.""To help some of the newcomers" #introductions

#Photography
#Astrophotography
#Netherlands
#utrecht
#QuantumPhysics
#Philosophy
#Science
#Nature
#SCUBA
#Chemistry
#occult
#Biology
#bioalgorithms
#Programming
#ClassicalLiberal

This is EXACTLY what i wanted to build for years now. An automated boat that could stay autonomous for months on end and travel across the ocean. Oh well I'm glad someone did it.

http://www.sciencemag.org/news/2018/03/fleet-sailboat-drones-could-monitor-climate-change-s-effect-oceans

#robotics #drones #ocean #science

I have a piece of amber a few million years old with about two dozen insects fossilized inside. I'll post macro shots of the various insects in the replies, as well as additional information.

#fossil #fossils #amber #science