Pierwsza część artykułu dostępna jest tutaj: Tropo: Więcej radia w Nowy Rok!
Do północy brakowało już kilku minut daleki dukt osłabiał się i zbliżał się wgłąb naszego kraju. SR P1 z szwedzkiego Hörby (486 km) dobijało do 41 dBf. Niestety przez mocne stacje obok odbiór został mocno pogorszony.
This year’s winter in Poland has been very mild so far and it does not resemble this season in our country at all. In fact, it is more like late autumn with possible light frosts. The forecasts for January are still in line with current weather, so this month will be definitely warmer than average. Starting from the end of December 2019, subsequent high pressure systems began to move to Poland. Such weather favors good propagation conditions, which can significantly increase the range of radio emissions. An inversion in the troposphere can enhance the reception within a wide frequency range, starting from the lower VHF (typically 50-70 MHz), through broadcast radio, television, microwaves and finally even… optical waves.
I have been using my Dell Latitude E7440 laptop (i7-4600U / 16 GB RAM / 480 GB SSD) literally every single day for almost 6 years. I still say this is one of the best laptops ever built. I’ve been looking for a upgrade for quite a long time though. However, I could not wait any longer, because my current laptop would require some expensive investments, including new:
In fact, no wonder that I could not find anything suitable for a very long time, because my requirements for a new laptop were very detailed and specific.
I’ve been lately looking for a small 10/100M Ethernet switch with a USB and both PoE input and output port (Power over Ethernet). The MikroTik RouterBOARD hAP (RB951Ui-2nD) looked pretty good, so I ordered one. The 2.4 GHz Wi-Fi interface was unnecessary, but the price was acceptable anyway, as I found a used device in excellent condition at just $25 including shipping.
As usually, the first thing I did after receiving the package was the teardown. The PoE ports are usually dedicated for some remote devices connected with long Ethernet cables and located outdoors. Therefore, a special protection should be included in the front of the controller (QCA9531 SoC in hAP). Unfortunately, this is not the case of RB951Ui-2nD. Although the engineers designed the PCB of this device with TVS diodes on both PoE input and output ports, the final product does not contain them. Protection for other ports was not planned at all.
Listopad nie był zbyt korzystny pod znakiem propagacji troposferycznej. Powiedziałbym nawet, że panowały często warunki ujemne (sygnały niższe niż zwykle). Patrząc na mapki troposferyczne myśleliśmy już, że na kolejne porządne tropo będzie trzeba czekać do 2020 r. Ku uciesze DX-erów grudzień przyniósł nam jednak wyczekiwany dukt.
Recently I’ve got a genuine Arduino Uno R3 from my friend to repair. The problem with his board was actually very generic – it has just stopped working. Personally, I don’t buy such boards, because they are extremely overpriced. I have been using several Chinese clones around for years and I have not encountered any problems so far.
At first sight, the USB interface was working fine and the board was detected by the system without any problems.
Recently I was traveling by plane over Europe. Of course, I could not resist to check what could be received on 5 GHz there, at an altitude of over ten kilometers…
I took the following equipment for Wi-Fi scanning onboard:
I was scanning using MikroTik SXT antenna with a built-in radio module (AR9280). This device is as small as 14×14 cm. The dual-polarization antenna rated at 16 dBi is even smaller, at just 11×11 cm. It was connected to Raspberry PI single board computer.
