Reflections about a remote mediumwave listeners station

The horizontal loop is my second antenna type in the garden. The closely placed, meanwhile leafy trees, additionally complicate the mounting. The wire is 2 mm green-clad steel wire, which proved to be excellent tensile strength. He was purchased at the hardware store for 0,06 € / meters.

The connected 55 Ah car batterie delivers electricity for about 5 hours. The current flow then went down from 19.5 V to 17.5 V. The notebook electricity changed for that reason with continous beeps between external powered to accu. There should be more power available. The max. notebook need is 4.74 Ah, so this batterie has to be changed or charged again after that time. To prevent discharge of the battery, a voltage monitor will be switched between, next.

The Rocketek voltage converter radiats HF of about 10 dBm between 6 and 30 MHz. The tropical bands and medium waves are clear as without a converter. I will try to add some ferrit to the charging line next. On some low frequencies are wobbler to hear. It could have been worse. The device was bought blind.

On the picture you see Audioengine D1 above the ELAD. This device delivers digital audio through USB and is classes better than the notebook built-in audio chip or card. Particularly at low incident transmitters he brings a barely surpassing clarity. Another pleasant advantage is the volume control by hand.

Best log 2day was VL8K ABC Darwin 2485 kHz 2053 UT SIO 252 running in // to 4835 kHz SIO 252.

In the coming days, the power supply is established. For now serving a 12 V car battery without solar panel as a power source. The inverter is a Rocketek voltage converter. Also to be seen whether the voltage converter radiates HF and how good the battery is to continuous use. First tests will be run with a Notebook, not the Tablet. As the Windom comes in July a 8-m NASA PA-30 works with the ELAD FDM-S2. Coming also in July is the solarpanel and a shower behind the hut.

Even without Power Bank possible

How does the tablet with mobile solar power? Connected was a RAV Power 15 W solar charger under the most favorable conditions: sunshine. There were used the ELAD FDM S2 / SW2 recorded files. The tablet ran under load with Wi-Fi, bluetooth and 100% display illumination. The test conditions showed that this use is quite possible for some hours. The solar charger provided through enough power to operate continuously.

As I wrote the other day, first tests with recordings on the ELAD FDM-S2 shows a limitation of the bandwidth to 2457.6 kHz. More is not stutterfree.

The picture shows another useful device to operate on the Tablet, a Logitech MX Master bluetooth mouse. The device can be programmed in many ways. It is, for Instance possible to change by keystroke between different types of modulation and to adjust the volume.

66 Min for free

No external AC power, the tablet can only with battery operated. The test environment is set to these values:
98% charged battery, Power saving mode, off screen: never, 0% brightness, volume level 100%, Bluetooth and WLAN off.
During operation, the USB connector must sit well, otherwise breaks the connection to the SDR. FDM-SW2 was set at a fixed frequency. After 40 min., the remaining battery life is reduced to 24%. After 60 min. is at least 6% of battery life available. After 66 min. with 5% left, the system will shut down automatically. The waiting time until the full charge is 2 hours with mains charger.

I didn't come to any solution working with this ext. powered hub. The Tablet didn't charge and run the ELAD FDM-S2 at one time. Following a tip I cut the ground line of the mini-USB-connector, but this didn't work either. It's reconnected again. I tried to connect 470 Ohm resistors in both data cables of the connector. (As described in Perseus_SDR Group)
According to the Perseus_SDR Group link the resistor should be set only between line A und B, but this does not work with the Tablet either. Connecting 124 kOhm and 36,5 k Ohm resistors (from: ... searchtips) in the same way did not work either. May be it's all bullshit.

At this time I dont see any chance to charge and run the ELAD FDM-S2 in parallel with this Trekstor Surftab wintron 7.0.

Overall, a good image. Little does what it should, but has due to its size limitations in regard to convenience. Since it is used only as a recorder, the restrictions appear first low. More remains to be seen in the continuous operation.

- CPU usage 11% -15%

- Total CPU usage 30%

- Audio quality: medium. Can be enhanced by a ext. audio amplifier, audioengine D1 e.g., which is actually not working on a hub w/out ext. power.

Just to confirm how the Trekstor Tablet works with the Logilink UA0140 Hub (without external power supply)

USB-in cable connected to power line
Connectors:
Pos. 1 Ext. HD 2TB = tries to connect but fails
Pos. 2 FDM S-2 = connected, but offline
Pos. 3 Tablet = charging

Introduction:

At my home QTH I am using the ELAD FDM-S2 with SW2-Software and Studio 1 Software. The Receiver is connected through a bifilar choke to a ALA 1530s+ under the roof. It's all grounded at the gutter. The antenna is controlled by a rotor. All cables around me are equipped with ferrite cores. Under good flow conditions the noise floor is at -120 dBm on MW and -130 dBm on the tropical bands. Under bad flows the noise level reaches -100/-90 dBm which is unacceptable for listening. A garden QTH may be a good alternative.

Living in Giessen/Germany I started Dxing in 1969 for some years and came back after 35 years of "silence". My interests are still utility, tropical bands and new, medium wave Dx. I am now not a QSL-collector any more but keep recordings of my stations heard. A small amount of recordings can be accessed here: dxerscorner on youtube

For many years I was attacked by man made noise on my local QTH. Now the time has come to fight back. A shortly sqattered garden area is tested and found to be suitable for nearly unspoilt reception on the bands.

This blog will continue with the latest developements on my Dxing in the garden.