English – FMDX.pl

My Commodore 128 repair journey

by qrzy17-07-202217-07-20220

What could go wrong if you buy a broken retro machine for cheap just to repair it and make it shine again with VIC-IIe colors and sing with glorius 3 channel SID chip? It’s not as easy task as I thought earlier and this repair went for much longer and costed me way more as compared to my previous Commodore 64c repair. Despite all the time, money and effort I put into it I don’t regret it at all. This repair allowed me to learn A LOT about electronics and electronic repair.

My mighty fixed Commodore 128 in it’s full glory.

Fixing Airspy HF+ Discovery VHF interferences issue

by qrzy17-07-202217-07-20224

A few years ago I bought the original dual port Airspy HF+ and was amazed by it’s reception quality. I’m using this sdr receiver up to this day for both HF and FM DX-ing and couldn’t find any other affordable yet so good receiver. Back in 2021 I bought Airspy HF+ Discovery as a replacement in case my dual port receiver is struck by ESD during lightning storm or something else.

Most noticeable differences are lack of metal casing which if present, could be useful in noise and interference reduction, and it has only a single SMA port which is fine for simple setup with single wideband scanner antena, but it’s definitely problematic for someone using separate HF and VHF antennas for better gain and performance. Similarly to dual port model, this device also uses micro-USB port which can potentially cause some troubles. If you stumble upon a connection problem when your computer doesn’t detect a device, or does detect but for some reason SDR software can’t connect to it, please check your usb cable. In my experience even good looking cables with no visible damage to the plug can be faulty, that’s why I’m using my trusted high quality cable filled with ferrite chokes/beads.

Dell Wyse 5070 – Home Server

by kkonrad23-06-202217-07-202223

Recently I have upgraded my home server to Dell Wyse 5070 Extended. This is a very interesting low power computer in a small form factor. My unit came with Pentium J5005 CPU, 8 GB DDR4 RAM (2 × 4 GB), an Radeon E9173 PCIe graphics card and a M.2 SATA SSD drive. The case is really nice, but the Windows sticker is not. There are many ports around, but I’m not going to use most of them anyway.

My previous setup based on Celeron J1900, 16 GB RAM and Intel 730 SSD has been working fine for 7 years with many services, including FMDX.pl website. I decided to build a new Linux home server, which could also be sufficient for such a long time, while still keeping the power consumption at a low level.

Raspberry PI 4: PoE with LM2596

by kkonrad09-01-202115-01-20224

During last Black Friday I bought Raspberry PI 4 on Aliexpress for just $36. After initial tests I’ve found out that a good cooling case is definitely a must have. The SoC quickly reaches 80°C under a full load and then throttles from 1.5 to 1.0 GHz per ARM core to maintain the temperature limit. So, I ordered a very nice Chinese aluminium case for just $7.5. I love PoE devices – my new toy must also support Power over Ethernet – and it does!

I took a cheap LM2596 DC converter and installed it together with the board in the aluminium case.

5 GHz Wi-Fi DX record – Denmark logged in Poland @ 745 km

by kkonrad15-08-202010-02-20221

A remarkable tropospheric ducting occurred on August 11 and 12, 2020 between Poland, Sweden and Denmark. The propagation forecasts, which use color hue to scale their intensity, featured red shades over the Baltic Sea. Such a propagation strength is very rare, if ever seen on a forecast for this area. I was looking forward for something extraordinary, especially on the microwave bands. My stationary Wi-Fi DXing setup has been damaged three months ago. I could not miss such an opening, so a DX-pedition was the only option. In the evening of August 11 I made an opportunistic decision to visit the Dylewska Góra in north-eastern Poland. A few hours later, I was standing there with an antenna inside a lookout tower.

With its tip at 312 m ASL, Dylewska Góra (Dylewska Mountain) near Ostróda is the highest hill of the whole north-eastern Poland. There is a wooden lookout tower atop which provides fantastic unobstructed views between 175° to 340° azimuth with optical visibility up to around 50 km. The driving distance from my location is 135 km and I arrived there in two hours, in the middle of the night (2 AM). I knew that place as I have visited it already once with my friend. Back then in the 2018 we encountered a typical morning inversion without any notable long-range ducting (see the report: Early morning on Dylewska Góra).

New Year 2020: Excellent inversion over Poland

by kkonrad26-01-202002-06-20201

Ten wpis jest dostępny także w języku polskim: Nowy Rok 2020: Rekordowa inwersja nad Polską

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.