Author Archives: mario

DRM TX with HiQSDR frontend

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Yesterday i used my HiQSDR frontend for transmitting a shortwave radio signal in digital DRM standard.
I had to use the FPGA firmware version 1.2 which contains enhanced filters that allow modulation of signals with a bandwidth of up to 22kHz in IQ mode (+-11kHz around the tuning frequency).
Stefan, DL2STG, did a great job creating support for the HiQSDR within the Gnuradio project. After noticing a IQ swap the 64QAM DRM signal was decodable. See the constellation diagram below.

HiQSDR DRM TX constellation diagram

HiQSDR DRM TX constellation diagram 64QAM

HiQSDR and HiQScope

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Recently Jim, N2ADR released a new version of his FPGA code for the HiQSDR/N2ADR frontend. This brings improved TX filters that should now also support FM and DRM TX. Stefan, DL2STG ported his HiQScope extension to the new Verilog code. This made me want to give it a try. It is really impressive how this makes the HiQSDR a 60MHz Bandwidth spectrum analyzer with waterfall functionality. And it can run in parallel to the regular transceiver application.
The screenshots below show the unfiltered spectrum from a short mobile shortwave antenna. The big signals above 16MHz are images of the extreme strong FM radio stations that i have here. Below the shortwave radio bands can be seen.

HiQScope Waterfall

HiQScope Waterfall view


HiQScope Spectrum

HiQScope Spectrum view

HiQSDR TX

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during weekend i took a screenshot of the TX signal quality of my HiQSDR PCB. As example i put the IMD spectrum for 10m here.
Looks quite nice, doesn´t it ? Its the DAC signal amplified by MMIC. I think it was around 6dBm output power.

HiQSDR_IMD_28MHz

HiQSDR_IMD_28MHz

QtRadio + gHPSDR-server

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I tried QtRadio + the gHPSDR-server which now also supports the HiQSDR frontend. The server runs on the PC connected to the frontend. The QtRadio application can run on another PC and can also be connected via Internet. The server supports Softrock radios and the Perseus as well. TX support is in progress. It is also possible to share your radio with others this way.

QtRadio

QtRadio

DARC 10m Contest

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today 10m contest from Bayerhoehe nr Dresden. I used my new 4el and a vertical. The vertical was nearly useless this time. My internet connection did not work. Rest of the rig worked perfectly fine. I just should have spend some time on try some test logging before. So i had some trouble with CW makros during the beginning of the contest. The conditions were really poor. Signals from stations in the south of germany had much multipath which made CW signal sometimes understandable.

10m DARC contest 2012, Bayerhoehe nr Dresden

10m DARC contest 2012, Bayerhoehe nr Dresden

Yagi test run

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Today i mounted the 4el Yagi to the mast. I put the system to the garden in order to try how difficult it is to set it up alone and to do some measurements. Center frequency seems to be around 28.500 or so. I heard some US stations and was able to work K8CW in SSB with 5W only.
Nice start. Hopefully also successful tomorrow… Hope to hear you in the 10m DARC contest.

4Ele 28MHz DK7ZB

4Ele 28MHz DK7ZB