Customer report on the full duplex capable DX-Patrol Groundstation

Frank, DL5AAR, has tested the DX-Patrol Groundstation at his school. Here is his report about it!

At the beginning of this school year, I set up an amateur radio school station at my school, the Carl-Friedrich-Gauß-Schule in Friedland, and offered a corresponding elective course.

Through on the air activities on VHF and HF, the students gained first insights into our great, versatile hobby. The possibility to talk by radio via satellite aroused a lot of interest. The wish for a school radio contact with Neumayer Station 3 in Antarctica was quickly expressed. For the first attempts on the satellite I took my portable QO-100 equipment with an 80 cm offset mirror, DX-Patrol ground station version 1 and FT-817 to the school. The enthusiasm was great, so the school's own equipment was needed.

A 60, 80 and 100 satellite antenna was available for a small budget through classified ads. We took three sizes for testing and comparison. The modified LNB was donated by Mathias DO6EP. Patric DC8PAT provided us with his latest version of the Ice Cone Feed 2.1. Otherwise we continued to operate with my ground station and FT-817.

Radio operation via the QO-100 sat offers many possibilities for experimentation and do-it-yourself constructions. Here the experimental character of our hobby can be brought closer to the students. I limited myself with the pupils to the experiments on the antenna side and printed e.g. the housings of different helix antennas with the school-owned 3D printer.

So why the DX-Patrol ground station?

For a club station, I think it is important that all users can safely operate the equipment after a short briefing. This is especially true for a school station. Complex solutions with Adalm Pluto and SDR console or many individual components were considered unsuitable or seemed too complicated to me. So the already known ground station by CT1FFU, DX-Patrol was favored during the research for an "all-in-one device" solution. Also for me privately this compact solution offered itself for the use in the camper while travelling.

For the first version of the ground station we needed a 70cm radio for up- and down-link. This is not full duplex capable, i.e. you cannot hear your transmissions directly back. This led to discussions in the net, because the ground station did not comply with the AMSAT guidelines. I solved this "problem" by means of Websdr on the cell phone or notebook or SDR stick at the second LNB output.

The school contact to Antarctica came closer, the "new" ground station made us curious

In the meantime a date for the radio contact to Antarctica was confirmed by AMSAT. Now the idea came up to test the "new", full duplex ground station with the extended features in the context of this planned connection and to compare it with the first version. At this point a big thank you to WiMo Antennen und Elektronik GmbH, who provided us with the current version of the ground station for this purpose.

DP0GVN for DL0CFG, please come in

The big day was here. Many hours of preparation payed off very well. Beside the main station with a 100 cm offset mirror, 10m Ecoflex10 coax cable and full duplex ground station on an IC-7100 and Funcube Dongle, there was also as backup an 80 mirror with ground station version 1 with FT-817 and each 3.5 turns helix in readiness.

This was not needed, our connection to Antarctica worked flawlessly and the students got their numerous questions all answered. Charly DK3ZL, as coordinator for the school contacts at AMSAT-DL, had a special surprise for us, when suddenly the german research vessel "Polarstern" (DP0POL/mm) called and sent us her greetings.

Ground station version 1 vs. ground station version 2

In the following I would like to discuss the similarities and differences between the two versions. Version 1 comes in an aluminum colored case with blue-green bezels and a monochrome display. Version 2 makes a more elegant impression with its completely black case and colored display. The housing size of only 33 × 22 × 18 cm is identical for both. Both devices can be operated intuitively. In the first version, nothing can be set; in the monochrome display, only the various status messages can be called up by pressing a button. The output power of 10 watts can only be controlled via the input power on both devices. 500mW was enough for us at the 100 mirror and 10m Ecoflex10 to produce a great signal from S9. Maximum input power is 5W for both devices, but this should not be exhausted. In our tests, there were slight overloads.

On the rear side of the radio are all connection possibilities. Version 1 has all connections, except PTT (Chinch), IF and reference out (F jacks), with SMA jacks and can be adapted to the N jacks/plugs of antenna and radio with the included cables. Version 2 has an N jack at the output of the power amplifier. New with version 2 is an additional RX output with SMA socket, via which full duplex can be realized. No further adapters are supplied with the new version. The power cable, GPS antenna, four F connectors and a DX Patrol LNB are included.

The new ground station offers, apart from the full duplex, additional setting possibilities, which extend the application possibilities. Different frequency ranges can be used for transmitting and receiving. RX and TX can be set in two of the following ranges: 28Mhz, 50Mhz, 70Mhz, 144Mhz, 432Mhz and 1295Mhz. For simplex operation, RX and TX frequency ranges are simply set the same and the TX/RX jack is connected to a radio. For full duplex, the RX/TX jack is used only on the transmit side, while the RX jack on any other frequency band (not the TX range) is provided with an appropriate receiver (e.g. radio or SDR stick). I have tried both.

Attention: Prevent transmission into the RX socket under any circumstances, in order not to destroy the ground station!!!

When changing frequencies with two TRX, both frequencies must always be adjusted the same. When transmitting (with both groundstations) it is noticeable that the decay time of the HF vox could be a bit shorter.

While the first version only has the button for the status displays and the power switch as operating elements, version 2 replaces the button with a rotary pushbutton switch with intuitive one-button menu navigation. The menu items are selected by rotary movements, released by pressing, changed by turning and confirmed by pressing the button again.

Variant 2 has an easy-to-read color display. In case of bad SWR (< 3) of the transmitting antenna, the devices switch off and a warning is given. Besides the temperature in the device, time, locator, coordinates, current output power, SWR and number of received satellites are displayed. New with variant two is the possibility to realize a FW update via WLAN.


All in all, the concept of the current ground station has fully convinced me. The few necessary settings are advantageous, although a manual power setting would certainly be interesting. Also the vox-delay could be a bit shorter as felt, can perhaps be adjusted internally.

It was great fun to work with the current Groundstation and directly compare both versions. The current version is a good evolution from version 1 and we will purchase this for the school station if we get it funded.

Vy 73 Frank, dl5aar

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