Satellite LNB are quite cheap and easy to get devices. There are different models for different bands (C, Ku, and Ka) with different characteristics like SNR, noise figure, etc. Typically those devices are used with TV Set-top boxes. More interesting is that LNB can be easily connected to an SDR receiver. LNB is a simple frequency down-converter with an output…
Category: Electronics
Mysterious Flat satellite antenna from China
A few months ago, I found a quite unusual satellite antenna on the well-known Chinese portal. The antenna was relatively small, completely flat, and declared as a Ku-band satellite TV antenna. I was really wondered what’s inside and how it works so I decided to buy one sample.
Reworking linear polarization satellite LNB into a circular polarized
In this article, I want to discuss different types of satellite LNB, polarization, and depolarization of waves. Also, I’ll show how to rework the LNB. Also, we will discuss a theory to figure out why this rework is working. The primary topic here is Ku-band LNB, but all this also works for the Ka-band and C-band.
Combining two HackRF SDR to see more
HackRF One is a popular SDR transceiver and a really nice piece of hardware. For a reasonable price, you can get fully open hardware to monitor radio signals in a wide range (20MHz – 6GHz, but really up to 7GHz). Boards support external clocking and can be easily customized. I believe there is only one concern about this board is…
Cheap single-component RF filters
Low, Band, and High – pass filters are major components when working with RF. Depending on the application, filters can reduce output noise and unwanted signals or limit a transmit signal to a pre-specified frequency band to prevent interference with other signals. Here I want to describe how to build simple and cheap single-component (ceramic) filters for your DIY projects.
RS-485 practice and theory
I just built two RS-485 adapters (version 2) and decided to write a little note about the RS-485 bus (and differential line) theory, plus perform some testing of the devices. This material mostly interesting for newbies. At the end of this article, you can find a funny way to test these devices 🙂
Dish antenna for the amateur radioastronomy
In the previous article, I describe a low noise amplifier for the 21cm band. Today I want to show you a construction of the dish antenna where this amplifier was used.
Isolated USB to RS485 adapter version 2
This is a second version of the USB to RS485 adapter. Please read this article about the first version. The new device is built with ISO3082 and requires fewer components. Also, this device can provide more reliability in some situations.
Low noise and low cost amplifier for radio astronomy, 21 cm band
21 cm band, also known as the Hydrogen line, is one of the important bands in radio astronomy. Please read this Wikipedia article if you not familiar with the Hydrogen line. Nowadays, even radio amateurs can observe this signal from outer space, thanks to modern hardware. One of the most important parts of any receiver is the antenna and input…
Powerful DC motor driver using IR2110
To control the DC motor’s speed and rotation direction, we need some motor driver. One of the most popular schematics is H-Bridge. For the low current and voltages, we can use some integral solutions like L293D and so on. But if we need more power and reliability, we have to build some custom H-bridge using Mosfet transistors. This type of…