@KB7ZUT

RF junky who escaped from a rehab facility

Joined December 2019
  • Tweets1.3K
  • Following479
  • Followers951
462Media
I can always find room in my EE toolbox for one more…
Pieter Ibelings
@ibelingsOct 13
Designed my first RF diplexer in 1993 on a VAX minicomputer. Tens of millions of my plug-in filters ended up in cable HFC amplifiers and fiber nodes. Now I’m giving the tool away: VektorFIL, free and open source. Butterworth to elliptic, coupled resonators, diplexers. Real synthesis, live schematic. github.com/ibelinp/vektorfil
10
322
So we are going to setup a notification system with China to alert each other when AI has gone rogue 👌 . Maybe we can automate the monitoring and alerts with AI. What could possibly go wrong 🤷 #AI
1
67
I was bitten by an Alias this morning. Not sure if it's poisonous or not. Nasty and fast moving. #rfengineering #RFDesign
3
10
615
Doing a little "Armchair Engineering" with the Digilent AD3. Using the built in Eye Patten tool to measure the jitter on the relaxation oscillator I made for my inverter project.
6
281
Kind of explains my love / hate relationship with math…
The Math Zone@TheMathzoneeSep 19
3
480
I needed a not-so-precise oscillator for an inverter project and started to reach for a 555 IC when I decided to go a little simpler. I vaguely remember learning about this circuit in college, but I think we blasted pass to focus on crystal base oscillators for precision timing.
1
10
555
An amazing invention, but Uda really should get more recognition for the idea. Maybe that explains why he is not smiling in the photo. Yagi held the patent (1,860,123 issued in 1932) and later sold it to RCA.
HarmlessHAM
@harmlesshamCQSep 17
100 years ago, in 1926, the Yagi-Uda beam antenna was invented! A century later, it remains a cornerstone of directional RF.
1
5
273
Using a L14G1 NPN phototransistor and my Fluke 199C to measure the accuracy of my very mecanical LF shutters. The shutter is inaccurate but generally repeatable. In one case 3/4 of a stop off. I can make a simple exposure correction table to compensate.
4
3
29
1,121
One of the best tutorials on the Smith Chart I have ever come across. Interactive visuals that help you better understand the core concepts. Thanks to @DanielBogdanoff for posting about it first. Check it out. arenaphysica.com/publication…

What is a Smith Chart?

An interactive introduction to the chart at the heart of RF engineering.

arenaphysica.com
3
1
23
3,020
Very nice tool when you are short on space for that low band dipole. Check it out, #hamradio
Ondra OK1CDJ/OL0M🇨🇿/SV0SYH/J42T🇬🇷
@ok1cdjAug 26
If you're squeezed for space — small yard, apartment balcony — shortened/loaded dipoles let you get on the bands anyway. Built a browser-based tool to play with the trade-offs — coil position, Q, efficiency, Beta-Match, matching bandwidth — based on a great piece in #FUNKAMATEUR 9/26 (DL1JWD). calc.ok1cdj.com/short-dipole… #hamradio #antennadesign #hamradio #antenna
2
5
370
I still have plenty of issues to work through, but I was able to hear several stations on 40m with my home brewed tube Direct Conversion Receiver this afternoon. One step forward… #hamradio
5
7
57
2,007
For the folks that want to learn more about the 6BN6 tube used as a mixer, Grayson Evans (KJ7UM) has a great blog post here: kj7um.wordpress.com/2020/12/…

The 6BN6, An Amazing Little Mixer

By Grayson Evans, KJ7UM, Copyright 2020 INTRODUCTION The 6BN6 Gated Beam thermatron is unique.  It’s constructed like no other thermatron I have ever come across in radio electronics. It was t…

kj7um.wordpress.com
1
1
1
30
1,824
Time for the mixer builder to enjoy a little different kind of mixing…
1
23
1,416
6BN6 tube mixer successfully mixing. And no fireworks in the lab! Last major part needed for the tube based 40m direct conversion receiver completed. #hamradio
3
56
2,273
RF Mixer Time! Gated-Beam Pentodes fresh from eBay for the tube based Direct Conversion Receiver. I’m really surprised how little these guys sell for.
2
16
413
A couple of coils, a dash of sliver mica caps and one 12B4 triode, and bam it’s an oscillating. And it landed in the middle of 40m. Not sure how I managed that🤷‍♂️. #hamradio
1
1
1
37
1,116
GlowFETs back on the bench!
1
1
41
1,422
After fixing this little mechanical monster, I will never complain again about SMT parts being too small.
2
12
460
Me: Just one more QSO, please. Mic Cable: I think you have had enough, sir… #hamradio
1
21
653
Can you spot the totally missing solder joint on my Siglent power supply encoder ground? It has been slowly driving me insane for the last couple of months. Me: Just increase by 50mV please. PS: how about going all the way to the 32V limit in one step…
2
12
738
Load more