The fundamental RC circuit ☺️
The starting point for many electronics tinkerers, moving onwards from simple DC designs. Found within the first couple chapters of any electronics textbook.

As simple as it may look, there’s surprisingly much to be said and understood about this circuit.

People will say “it’s a low pass filter” (or high pass)”, but how does it actually work, why does it act as a filter?

To understand its frequency behavior, you need to look at it in the time domain.
Two simple components, a square wave signal and any oscilloscope will keep you entertained all night 😃👍🏼

Last week I found myself busy a couple hours at the whiteboard at the local #hamradio club, explaining a lot of this.
Tuesday night, we’ll set up measurements at the bench demonstrating last week’s calculations, it’ll be fun 🙂🙂

#electronicsengineering #electronics #retro #engineer #hamr #testandmeasurement #siglent #rohdeschwarz #circuitdesign

A small walkthrough of my hydrogen line radio telescope, seen through an app which does a really cool AR overlay of the Milkyway.

What happens when I point the antenna to a vertical position, far away from the galaxy?
To things: 1) the 1420MHz signal disappears and 2) The noise floor drops several dB. Effectively this means at I’m picking up ground noise at this low view angle 👌🏻

#radiotelescope #astronomy #radioastronomy #rfengineer #rfengineering #hamradio #hamr #siglent #frequencyfriday

10 years back, I started experimenting, building my own radio telescope. My results, trying to observe the Galaxy hydrogen line at 1420MHz, were positive but in no way impressive.

Years have passed, I have better test equipment today, I have my own lab and I have a better antenna 🤓 📡

So I decided to give it a go last night - and it worked!

Not ideal a summer evening like this, the sky temperature is too high, and my observing angle too low, but at least I proved it possible, it’s a nice starting point 🙂🙂

My setup is a vintage 17dBi standard gain horn and a 38dB LNA, cooled about 20degrees below ambient. I feed this to my spectrum analyzer.

Next step will be to build a larger antenna and try again with when everything cools down in the fall 🙂

I really looked forward to share this - I hope you appreciate it 👌🏻☺️

#radiotelescope #astronomy #radioastronomy #rfengineer #rfengineering #hamradio #hamr #siglent #frequencyfriday

Now, to get around to the two #logicanalyzer pods and all the grabbers. I had code that would run fine from the #89C52 memory, but wouldn't run from the #eeprom. I had verified that the static ram worked, but the EEPROM seemed to be acting odd. My nice #Siglent scope only has 16 logic channels. Not enough to watch the latched address bus and the data bus. Yes, I could have done it, but why not break out the #HP1532B? Plenty of channels there.

So how was your Friday evening? 🙂

I spent mine testing a HMC588 VCO module and a couple mixers: mission was to extend my measurement reach to cover x-band, aka 10ish GHz ☺️

After a quick DC test without the VCO board blowing up, I moved on to test two mixers: a ‘Magnum Microwave’ 4-12GHz and a LTC5549 based device, good to 14GHz.

All went well, those two peaks are at 10 and 11GHz so my spectrum analyzer extender setup works just fine 👍🏼🎯

#hamr #hamradio #electronics #rfengineer #electronicsengineering #siglent #ghz #highfrequency

Got myself a new lab equipment.

An arbitrary waveform generator, Siglent SDG1062X.

#siglent #sdg #awg

I think we found the TX line! Baud rate is somewhere around 1.5Mb. #oscilloscope #reverseengineering #siglent #serial #protocoldecoding.

Even though quite rudimentary when RF and electronics is your job/life/passion, sweeping a filter is always a pleasure 👌🏻☺️

This is a 10MHz band pass, meant to be used with reference frequency distribution 👍🏼

Running a square wave through it produces a beautiful sine 🥰

#rfengineer #electronicsengineering #testandmeasurement #siglent #hamr #hamradio

Mailbag Wednesday: new ADF4351 RF generator, unfortunately I can’t afford a pro one.. 🤷🏼‍♂️🙂 So rich on harmonics, but quite ok on phase noise. And it has input for an external reference 👌🏻

Also, new handle and bumpers for my #agilent counter (looks like new now 😃) and a handy little cable stripper/cutter for the small diameters: AWG 20-32

#electronics #siglent #hamradio #hamr #electronicsengineering #testandmeasurement

Looking at the same simple signal on my two oscilloscopes: my #vitage #Hameg and my fancy 4 channel #Siglent.

The Hameg picks it up easily, the Siglent doesn’t, what’s going on?

Back in the days we learned to “throw all levers at the upper position and you’ll catch something on the scope” and there’s a degree of truth to it. Doing that on the Hameg, sets the trigger to AC and it’ll immediately capture a DC offset signal like the one shown.

For some weird reason, every digital scope I’ve ever had my hands on, defaulted to ‘DC’ trigger, which forces you to adjust the trigger level pretty much every time you want to capture a signal.

I’ve now set my scope to default at AC triggering, it’ll cover me 90% of the time, and I can always use DC triggering if I need to capture single events at specific amplitudes.

#yourewelcome 🙂

#electronicsengineering #testandmeasurement #engineer #oscilloscope #tipoftheday #labrat

I built a simple #calorimeter and used it to prove that an arbitrary AC signal will heat a resistor equally compared to a DC signal with the same amplitude as the RMS amplitude of the AC signal 🤓
This a fundamental rule and the reason we universally use RMS to describe any AC signal amplitude: by the end of the day, everything revolves around power transfer.
A funny experiment involving many interesting disciplines: temperature measurement, building a small heating element, basic math/physics and some basic measurement techniques.
#stem #stemeducation #electronics #physics #engineer #testandmeasurement #siglent

Ok, next little project. The #QDX still has many secrets to me so to find out what makes it tick I ordered a cheap Si5351A oscillator board to play and learn. First task is to solder up the connectors, then hook it up to a #siglent scope to see what analog signals comes out. Then probably snif the I2C bus with the same Siglent or an old DS1054Z and use an #rasberry or #arduino to try to send control commands. Lots to learn.

Was ich als Hobbyist sehr angenehm finde, ist das einige Hersteller wie #Rigol und #Siglent die Leistungsfähigkeit ihrer Geräte oftmals Halbherzig per Software limitieren. So bekommt man für die #Elektonikecke für (relativ) kleines Geld sehr leistungsfähiges Gerät.

Auto-calibrating as part of a firmware update...

#oscilloscope #siglent