Reflections about a remote mediumwave listeners station

Next Unit of Computing → NUC:

Power consumption is ~15 W, 1,25 Ah at 12 V without Monitor. Running SDR-Console in recording mode with ELAD's FDM-S2 is up to ~20 W, 1,66 Ah. In this mode with the connected Monitor and under WIN 8.1 energy saving mode the consumption is ~30 W, 2,5 Ah. This is more than expected but less than the 90 W 4,74 Ah notebook. The BIOS is capable to WOL (Wake on LAN). This is not possible with the notebook. Also recordings can start out of sleep mode under WOSB. In this mode the USB port for the SDR is off and does not waste energy as it was with the notebook in energy saving mode. Waking up the notebook from sleep mode with WOSB was not possible. The device makes a solid impression; the case is made of metal and cleanly processed. The boards are clearly arranged and properly wired. The operating temperature of the fanless system is 42° under load with the SDR Console.

Monitor:

The screen ist only accessable under a running Windows. This means that access to BIOS and other functions are never available. Due to the low power consumption and no alternatives I decided to keep the device. If something goes wrong the NUC will be handled @home. The monitor has a direction sensor and adjusts the image according to its position. The screen comes with a HD resolution of 1920x1080 px and a fine viewing angle of 180°. To keep the length of the USB cable short, he spends his life standing upside down and mounted in a frame on a wooden wall. The controls are also easier to handle in this position. The weight of this device is 800 g. It is one of the thinnest monitor on the market with 8,5 mm.

Both:

RFI on some QRG's on MW, seems to be irregulary and "adjustable".

All in all:

Better audio or less RFI compared to the notebook. Can be fixed with screws on the desk. A very good performance due to less installed software, i7 Kaby Lake prozessor, 8 GB DDR3 RAM, SSD and 64 Bit OS. It is the fastest device I ever had. Manufacturing & delivery time from Taiwan was ~14 days due to 春节 Chinese New Year 2019, the year of the 猪 Pig. First tests showed no delays in automatic recording. All devices are working perfect together.

Power consumption measured by Solar charging module:

Screen: off | Air-sun-solarsystem: off | Recording mode: on | balanced energy mode WIN 8.1:
1,7 Ah without K9AY
1,9 Ah with K9AY
2,4 Ah with screen
2,5 Ah with Air-sun-solarsystem
2,6 Ah with light in the hut
2,9 Ah with 2nd light
3,4 Ah with 3rd light

The cube has fallen: alea iacta est, as it is called in Latin, if after a long time a decision has been made. In more modern times translated: the winner is a 15.6-inch mobile HD TFT LED screen of the Asus MB 169B+ Brand with a power consumption of 5 watts at a weight of just 800 grams. Although the USB-controlled monitor significantly exceeds my price limit, but also put all the other monitors in the selection, due to the low power consumption in the shade. An interesting effect of the weeks-long search was that smaller monitors tend to consume more power, or the size of the monitor is not necessarily crucial for power consumption. Originally I was looking for 11.6 and 13.3 inch monitors. Only the search for larger models brought me into the optimal power range. Furthermore, the German market is hardly well covered with smaller monitors, which is why I initially searched the Chinese market of a large provider. Another reason to buy locally around the corner was that in the case of warranty the effort is low. Although the previously purchased NUC comes from China, but here I trust more on the longevity of commonly used hardware components. And yes, the monitor has a drawback, of course: due to its small depth, it can not be obstructed against the wall. So here again handmade is announced. The egg-laying "Wollmilchsau" has not yet been born.

The next step is the search for a suitable Ethernet to WLAN bridge for the NUC, so that the small one can be switched remotely even when switched off. This should then be the last search, because a keyboard for the Mini already exists.

He is not yet set up, but he should secure the future of the station. A fanless NUC with i7 processor, 8 GB RAM, 256 GB SSD, WiFi and all possible connectivity is on the way. The decisive factor for the investment in new hardware was the fact that it further reduced the power consumption of the solar-controlled system and also enabled real remote DX. The supply voltage is 12 V; a disturbing power supply is no longer necessary. The mini-computer should consume 15W, a halving of the power requirement compared to the 17 inch notebook. A wireless Wi-Fi connection to a server near the site then takes over the remote function. The latter is so conceived, but whether the reality plays along, is first left undecided. WIN 7 will control the plant, and Teamviewer will connect two PCs. First, as usual, everything has to be tested, and that will happen in the home QTH. At the moment the decision for an external monitor has not yet been made. I'm curious to see how many new RF interferences I have to contend with soon.

This section displays the status of my logged USA & Canada states. It will be updated.







List of abbreviations for states

Pin board at Google Maps

Status 17 January 2019

Heard states/green (USA): 27
Confirmed states/red: 0
Latest heard or confirmed: 1000 KOMO, Seattle, Washington

Heard states/green (Canada): 5
Confirmed states/red: 1
Latest heard or confirmed:

Map source: Free Software Foundation. The source has been changed.

You can find all the logs of the year here: logs_2018.pdf

One year is long, and sometimes it's better than the previous one. What does the station look like at the end of 2018?

The question is not easy to answer. I had to fall back on the notebook after the failure of the tablet. In a 220V environment no problem, but in the 12V mode, you are constantly confronted with run-down solar batteries. The solar system could be expanded to 10 times, and even then I would not be safe from failures. Therefore, I will keep the plant in its current status. But the reasons are elsewhere. The 12 / 19V voltage converter causes slight disturbances in the MW range here and there. They were not available in tablet mode, because the power was converted from 12 to 5 V with a length-controlled power supply. That's why I plan to buy a 50 Ah Lion battery in 2019. He should supplement the existing 22 Ah Lion battery. Together with the notebook battery, I would then come to a running time of 5-7 hours. That is still little, but a bit more comfortable with a corresponding operation.

The mediumwave band from 500 to 2000 kHz in the early afternoon. The formerly low-interference remote location is developing into a HF-picket fence. It looks bad, the disturbances can often be excluded by sidebands. If the signals attract, so after dark, you do not get too much of it. Only the SE leg of the K9AY hides the interference very strong. A disturber shuts off punctually at 17z.

Azimuthal Map
Center: 50°35'1"N 8°40'40"E
Courtesy of Tom (NS6T)



QTH: D-35390 Giessen/Germany

All 50 m Antennas are connected through a RPA-2 Preamplifier.
I am working on a 250°/ 70° direction.

On 24.10.2018 at 1624z I managed the reception of 5AN, ABC Adelaide on the frequency 891 kHz. The weak signal could only be identified with the help of the webstream. The 50 kW transmitter from the state of South Australia is my first Pacific broadcast on medium wave.

Actually, everything was not a problem. The components were assembled, the elements assembled, the wire roll positioned in a bicycle trailer, and we went out to the neighboring meadow. There, first the earth piles with the connection components were cut into the dry soil, then the galvanized 300 m cable was towed from point A (NE) to B (SE), the 80 m long coax was laid out to the hut, and the RPA- 2 connected. The first test showed remarkably good signals over the entire medium wave, no additional amplified noise due to the preamplifier, in short: the perfect antenna for receiving from the NE direction. A two-hour recording showed me later, how good 300 m antenna cable can be.

I sat in my garden hut in front of the waterfall screen and listened intently, likening the reception to the now weak K9AY, it was around 1930z when I heard voices unknown from outside. When they did not stop, I left my seat, walked to the shack, and watched a person slam through the blackberry hedge. I would not want to go through that, I said. Police, was the answer. In the light of the flashlight I could see the lettering on the man's jacket. In fact, I said.

Displaced dog owners carrying their Fiffies on the meadow suspect a power cord, the policeman said, while his companion expertly examined the coaxial cable. It's an antenna, I confirmed, and that's guaranteed no electricity in it. Good - the law did not come to the dicuting. Now the identity card was checked, a radio check was made, and then I was allowed to roll up the quickly mounted antenna again. So that the dog owners can perform their Fiffies again the next morning. We'll check that later, they said before I let them out through the official entrance to the garden. No, we do not want to go through that again, they said, and disappeared in the darkness of the night.

Days later, I realized that the preferred direction of arrival from NE was not guaranteed at all, because one earth point was in the wrong position. So it is not even a pity that the experiment did not work out. It was exciting enough, from planning to firing.

40 safe meters remain me, NE 4-5 m pulled over the impenetrable blackberry hedge, soon. After all, it's my garden, and I do not keep dogs.

Antenna building material for a 350 m BOG. The line should run in NE / N direction, be largely invisible, and waterproof. Most of the material comes from a pasture fence shop, secret slogan: "Your partner for good MW-DX". The antenna is placed as soon as conditions permit on the neighboring meadow.

For construction: The Beverage boxes are installed in watertight HT tubes, the cables are routed through watertight cable feedthroughs. The ground wires at both ends are bolted to the ground rods. An approximately 60 m long coaxial cable is laid underground to the shack. If necessary, the ring insulators are placed in the ground at long intervals, bolted to wooden bars to keep the BOG flat and tight.

The BOG is connected to an RPA-2 Modular Receive Preamplifier by DX-Engineering.

On 26.6. in the morning around 03 UT I was able to record good MW conditions to Peru. Overall, conditions have improved again after weeks of receiving very poor signals from South America. The following stations could be identified perfectly.

2018-06-26 (Screenshot)

1470 0245 PRU OAU4B Radio Capital, Lima/Pantanos de Villa (lim) ID 10752 km
1510 0250 PRU OCX6Q Radio Alegría, Arequipa (are) sev. Alegria IDs, strong 10739 km
1490 0258 PRU OCX4P Radio La Luz, Cerro de Pasco (pas) ID 10572 km
1570 0258 PRU OCU4J Radio Bethel, Lima (lim) ID 10732 km
1480 0300 PRU OAZ7G Radio Espinar, Yauri (cus) ID R Espinar 5685 km
1500 0300 PRU OBX4I Radio Santa Rosa, Lima/San Miguel (lim) sev. IDs

2018-06-28

1490 0300 PRU La Voz de la Liberación via Radio Cadena Sur, Cusco ID
(Thanks to Christoph Ratzer from Austria)

2018-06-30

1570 0256 PRU OCU4J Radio Bethel, Lima (lim) IDs 10732 km
1500 0300 PRU OBX4I Radio Santa Rosa, Lima/San Miguel (lim) ID 10745 km
1470 0305 PRU OAU4B Radio Capital, Lima/Pantanos de Villa (lim) ID, strong sig, long skip 10752 km

2018-07-02

1500 0303 PRU OBX4I Radio Santa Rosa, Lima/San Miguel (lim) ID 10745 km
1470 0306 PRU OAU4B Radio Capital, Lima/Pantanos de Villa (lim) ID 10752 km
1570 0337 PRU OCU4J Radio Bethel, Lima (lim) ID 10732 km

All Logs of 26-6-2018 by MW-LIST

Summer is the time to check or repair the station and antennas. The Beverage Antenna matching Set from lowbandsystems has been in a waterproof plastic box for over a year. Fortunately, no rust has formed, although - after opening - the waterproofness must be questioned. A new grounding rod was inserted and connected with thick copper wire. All openings for the pipes were re-sealed. Next check is in a year.

The 60 m long wire antenna, mounted in the direction of NW, works perfectly. The noise floor is about -120 dBm. It apparently has no pronounced directivity and can also be used very well as a South American antenna. However, signals from NE / SE are correspondingly quiet.