🎓 Dr. Freemo 🇳🇱 @freemo@qoto.org

Now that i added tilt to my DIY keyboard it is so much nicer. I think ill add the same to the numpad!

#DIY #Keyboard #Keyboards #Electronics #EE

My antenna on my roof as viewed from the ground.

#Science #Ham #HamRadio #amateurradio #radio #rf #EE #Electronics

If you do any sort of #Electronics work where you have to strip tiny wires of 20 AWG or less I highly recommend you get yourself a precision wire stripper.

#EE #ElectricalEngineering #HamRadio #Ham

My old antenna fell down after almost a decade. It performed so well i bought the same brand again and am putting another one back up today. Its quite tall (like 30 or 40 feet or sonething) and requires the whole roof to be covered in radials. This tine im coating the radials with tar to embed them into the roof itself. Quite the project but it will be worth it.

#ham #radio #HamRadio #RF #AmateurRadio #Electronics

In 12 hours my radio beacon was heard directly by a few fairly long distance stations for the frequency I'm working:

95 miles x2

104 miles x3

156 miles x1

92 miles x2

Sweeet!

You can see for yourself here:

https://aprs.fi/info/a/WI2ARD-1

#EE #Radio #HamRadio #AmateurRadio #Electronics #RF

Just saw some minor VHF skip or something... my beacon just traveled 155 miles to virginia from my roof... thats unusually far for 2m VHF....

#EE #Radio #HamRadio #AmateurRadio #Electronics #RF

I cant express how excited i am to have my station back up and runni g again off my own custom software... seriously this is awesome! Been waiting 2 years to finish this project!

#EE #Radio #HamRadio #AmateurRadio #Electronics #RF
QT: https://qoto.org/@freemo/110703577112585020

Managed to bri g the software i was writinf for #APRS back online at my station. It is working perfectly again. Beacons are successfully being sent and digipeating is working.

You can see the screenshot of the control terminal attached. You can watch the packets live here:

https://aprs.fi/info/a/WI2ARD-1

#EE #Radio #HamRadio #AmateurRadio #Electronics #RF

My VHF APRS beacon has now officially went live again after 2 years! You can track its packets and location here:

https://aprs.fi/info/a/WI2ARD-1

#EE #RF #Radio #HamRadio #AmateurRadio #Electronics

It is weird the things you miss when you are away from home for multiple years... friends aside its really nice to have my handy Fluke 289 DMM back in my hand.

#EE #Electronics #ElectricalEngineering

What open-source Electronics EDA would you prefer to use if you ran a team and learning curve wasnt an issue?

#EE #Electronics #Physics

Am i the only one who collects every possible chemistry of battery he can get his hands on?

#Electronics #EE

A little (now improved) AGC circuit I played with (designed to be simple not the best :) )

https://tinyurl.com/2nzryvuk

Also check out falstad circuit simulator ^^^

#electronics #ee

Know your diodes.

#Electronics

There has been a lot of discussion lately, much of it just plain incorrect, about the relationship between resonance and antenna efficiency. Many incorrectly claim that resonance has nothing to do with antenna efficiency at all, similarly others incorrectly claim that resonance is a direct indication of efficiency. Neither of these statements is true. The reality is that resonance does have a significant impact on how efficient your antenna is, but the relationship is highly non-linear and depends on many characteristics.

Below I have attached a chart hat plots out the total radiation resistance (R_r) vs the measured input resistance (R_in) of a dipole. Efficiency is just R_r/R_in. In other words an efficient antenna will have 100% of its resistance as radiation resistance, and R_in is **always** larger than R_r (since it is essentially ohmic resistance plus radiation resistance). When these two numbers differ significantly an antenna is inefficient. The source for the chart below is here and it gives much of the math if you want a deeper dive:

https://nptel.ac.in/content/storage2/courses/108101092/Week-2-Dipole%20Antenna.pdf

What is important to note here is that at anti-resonance we see a **huge** R_in value and a small R_r value, this means an anti-resonant antenna will have very high losses. Keep in mind the graph is very hard to read for the values <0.5 in length because the resolution isnt high. But there is significant divergence there as well. Notice at ~5/8ths wavelength antenna would exhibit very significant internal ohmic losses due to heat.

#hamradio #rf #radio #ee #electronics #electricalrngineering @Electronics

I have been looking for these since forever! Finally!

#EE #Electronics @Electronics

A wonderful site showing a few different types of radio signal **refraction**. Important to note what you are seeing here is totally different from the effects you get from HF radio frequencies and occurs with VHF and UHF as well. Its why generally line-of-sight frequencies like UHF can sometimes go some ways over the horizon.

https://www.dxinfocentre.com/propagation/tr-modes.htm

#Radio #RF #Ham #HamRadio #AmateurRadio #EE #Electronics #Science #STEM @Science

Here is the review of the Storm2 Liquid as requested (after owning for an hour or so). Not much to review really other than to make the following points.

This is a 93.5Wh portable emergency battle I just received one of the first copies of as an early kickstarter backer. It uses 8x 18650 internal Li-ion batteries.

The screen is loaded with tons of information in a very sexy high resolution display with an impressive color range. The info reported on the main screen and info screen are: Internal battery voltage and current, time running, input/output/combined current/voltage/wattage (so for example it shows what voltage the USB-c I/O are negotiated at), battery and CPU temp separately, it even tells you the internal battery voltage of each of the 4 parallel cells separately in addition to the combined battery voltage.

Not just the screen is sexy but the whole case really and you can see the 8 li-ion cells inside.

Comes with USB-C and DC-jack input ports that can also be switched to output ports. Has an additional USB-C output port and USB-A output port as well.

The DC jack acting as an output port means you can use it to charge non-USB devices and even comes with some alligator clip outputs for the DC-jack and you can easily buy standard output jack adapters to connect to any format dc jack imaginable.

Obviously the output DC jack setting lets you configure the voltage in 0.1V increments up to 25.2V, I think it handles either 3A or 5A output, need to check spec. However irf the DC-jack output is on as you adjust the voltage it updates the current out of that port in real-time which is useful.

Overall so far I cant find a single thing to complain about, this thing has all the data and features id expect and want and done as stylish as they could have hoped to do. IT is also about as small as you can get since 90% of the space is the batteries.

@zpartacoos #kickstarter #electronics #Storm2Liquid #storm2 #storm @Electronics

Wooootttt after a 4 month wait since backing it on kickstarter my Storm2 Liquid finally arrived (2 of those months was shipping time). Cant wait to plat
Y with this sexy beast.

#kickstarter #electronics #Storm2Liquid #storm2 #storm

I dedicated a shelf in one of my rooms exclusively for charging all my shit, including rechargeable batteries themselves. Pretty much everything but my laptops. My desk was getting way too cluttered.

#Electronics #Battery #Batteries #Organizing