## Search found 35 matches

Fri May 10, 2019 6:54 pm
Forum: Antennas
Topic: Antenna tuning, impedance matching, baluns, common mode currents, my head exploding...
Replies: 6
Views: 574

### Re: Antenna tuning, impedance matching, baluns, common mode currents, my head exploding...

I finally understand what a balun is! So I'm going to write this down in case some other confused soul comes along and tries to learn the same stuff. Anyway, what is a balun you ask? Well as it turns out I had the correct answer right underneath my nose all the time, but I was too confused with all...
Mon May 06, 2019 12:03 pm
Forum: Signal Identification Help
Topic: Decoding 433mhz windowblinds
Replies: 1
Views: 448

### Re: Decoding 433mhz windowblinds

Zoom in into one of those repeating signal chunks you see in audacity.
Sun May 05, 2019 2:30 pm
Forum: KerberosSDR
Replies: 7
Views: 512

### Re: Some questions about KerberosSDR

kb3cs: I was merely theorizing that it should not matter how strong the received signal is (assuming it is within the receiver detectable boundaries) because all antennas would see the same power/signal increase and decrease relative to each other. And assuming antennas are identical then the recep...
Sun May 05, 2019 2:13 pm
Forum: KerberosSDR
Replies: 7
Views: 512

### Re: Some questions about KerberosSDR

You could update the code if you could do the math and figure out the algorithm for various arrangements, I see, so it comes down to the algorithm then. but i'm not sure why you would want to do that. Other types of arrangement would be suboptimal, you'd essentially be sacrificing an antenna. Oh, h...
Sun May 05, 2019 9:29 am
Forum: KerberosSDR
Replies: 7
Views: 512

### Re: Some questions about KerberosSDR

Hey, thanks for the answers, I really appreciate it. KerberosSDR is 4x RTL-SDRs with some circuitry to make it coherent. So even if you're not using the coherent features, you can still use it as 4 independent tuners. So you could use a splitter to connect a single antenna to all four ports. I'm not...
Sat May 04, 2019 11:07 am
Forum: Antennas
Topic: Antenna tuning, impedance matching, baluns, common mode currents, my head exploding...
Replies: 6
Views: 574

### Re: Antenna tuning, impedance matching, baluns, common mode currents, my head exploding...

Get a copy of the ARRL or RSGB antenna handbook and you have the Basics in a simple form. Here's a snippet from the ARRL handbook 2017, chapter 21.2.3: Baluns A balun can be constructed in a number of ways: the simplest being to coil several turns of coaxial cable at the antenna feed point. This cr...
Fri May 03, 2019 3:42 pm
Forum: KerberosSDR
Replies: 7
Views: 512

Hello, I have some questions about this interesting SDR. What kind of antennas work best for direction finding? Can this SDR be used for wideband scans with single antennas or do antennas need to be changed per frequency/band? Can the placement of antennas be arbitrary? I've only seen a video where ...
Sun Apr 28, 2019 10:22 am
Forum: Antennas
Topic: Antenna tuning, impedance matching, baluns, common mode currents, my head exploding...
Replies: 6
Views: 574

### Re: Antenna tuning, impedance matching, baluns, common mode currents, my head exploding...

BAL UN or BAL (anced/ UN (balanced) is needed when you want to connect an unbalanced/asymetrical cable/antenna (e.g.coax) to a balanced/symetrical cable/antenna e.g. a halfwave-dipole. EDIT: After reading some more material online it seems like I was wrong about this one... Like I said, people will...
Fri Apr 26, 2019 11:23 am
Forum: Antennas
Topic: Antenna tuning, impedance matching, baluns, common mode currents, my head exploding...
Replies: 6
Views: 574

### Antenna tuning, impedance matching, baluns, common mode currents, my head exploding...

Hey, I was wondering about a few things on this topic... Suppose I wanted to wire up a DIY 433 MHz yagi with a folded dipole driven element. Technically speaking, what elements are needed to "complete" the antenna and for its good operation? Looking at the docs and designs I came up with this list: ...
Fri Mar 22, 2019 11:10 am
Forum: RTL-SDR Discussion
Topic: Yard Stick One - RF Transmitter Raspberry PI
Replies: 2
Views: 310

### Re: Yard Stick One - RF Transmitter Raspberry PI

You can probably buy some cheap transmitter module of a given frequency on ebay and drive them with a RPi/Arduino GPIO pin. You will however need to write or get some software or script that will handle the pin output to generate the required signal. For 433,92 MHz there are plenty of cheap modules ...