Category Archives: Amateur Radio

V/U/SHF Contest from JO60OM

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23cm setup with HiQSDR…

HiQSDR 23cm

HiQSDR 23cm transverter setup

Contest from Hirtstein. Qrv mainly on 23cm. Setup was composed new. The old 10m-23cm TRV, 2x100W PA, 1.5m dish, backside Quados-8. Changed the Transceiver to my HiQSDR. Seeing the complete Band at once is pretty nice. CW was done completely by keyboard out of VUSC. SSB voicekeyer also worked via a small audio switchbox made for that purpose. Problems upfront were dynamic microphone headsets not working properly with the soundcard input. In addition Murphy made my linear powersupply fail during testing the equipment which lead to a damage of the transverter. Luckily it was not too terrible ;)

DARC 10m Contest

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DARC 10m contest from Triebenberg JO61XA.  Rig: Hiqsdr, 100W class C amplifier, 2x deltaloop. Software: Quisk, forwarding 192kHz to CW-Skimmer, TLF filling the bandmap from the CW Skimmer spots and controlling Quisk. CW keying via cwdaemon.

I worked 49 QSO and about 1800 points. Points for improvement:

– change both antennas to horizontal

– use a passive switch for the antennas since the 12v->24v caused interference

– improve the filters for the bandmap (avoid hp stations, highlight multies)

The wheather was quite stormy and i had problems with the fibre mast. Conditions were very good with band wide open.

image

image

image

Hex-Quadlong for 70cm

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Since i needed a very lightweight antenna for 70cm for my fibre mast i looked at the Quadlong antennas published by DK7ZB. I downloaded 4NEC2 and started playing around. I simply entered the VHF version and scaled it to the available materials and 432.2MHz. To be honest i dont have a lot of knowledge about this simulation tool but the result looked promising. So i added extra segments at the upper and lower end of the antenna and rescaled it to get proper matching again. The result was promising again. >1dB more gain then before. I made the antenna from 4mm brass material for the horizontal elements and 1mm copper antenna wire for the vertical elements.
Some drawings of the VHF version you can find at the webpages of DK7ZB.
Thats what 4NEC2 shows (ask me if you need the NEC file)

70cm Hex Quadlong drawing

70cm Hex Quadlong drawing

70cm Hex Quados pattern by 4NEC2

70cm Hex Quados pattern by 4NEC2

BTW i dont trust the gain calculations of 4NEC2 at this stage. I did not simulate with another tool. Let me know if you do so. I can provide the NEC file i created. Just drop me a line and i send it to you.

Thats a photo of the antenna as i used it during the UHF contest:

Hex-Quadlong 70cm

Hex-Quadlong 70cm

Since i finshed when the UHF contest was already started Saturday i decided to glue the antenna to the mast by means of tape. VSWR showed not too good result on 432.2MHz. Tuning few MHz forth and back gave the impression that the resonance was too high.
Monday i had a look with the network analyzer. Indeed the resonance is about 6.5MHz too high. Thats how the measurement looked like:

Hex-Quadlong 70cm measurement

Hex-Quadlong 70cm measurement


Maybe i will do a slight rescaling of the vertical elements to shift it a bit down. Also the mounting needs to be improved.

VHF contest from home

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Due i was not able to join the DM7A activity from JO60LK this time i decided to try a few contacts from home in JO61VB. My location is in the Elbe valley at the eastern slope. I mounted a DK7ZB Quadlong antenna to my fibre mast installed to the balcony. Find some report on the antenna here: http://dh5ym.hopto.org/wiki/?p=1138
Only 50W were available from my FT-857D transceiver because the PA was in JO60LK serving as spare.
Surprisingly even with this tiny setup from a that bad location it was possible to make some DX contacts. I just operated about 4.5hours and got 57QSO with about 190km average.
In the map the directions of the Elbe valley are clearly visible. Especially direction of Poland i was not able to work anyone. I had the impression that relatively few stations were calling CQ. Maybe that was just related to my poor RX but possibly that trend continues to move from the microwave bands to VHF as well. Using ON4KST chat it was possible to arrange for some nice contacts in addition to a few random QSO.
ODX was PA1T with 535km. Others in top 5 are S59P, HA2U, DL0LN and OM3CPF.
Many thanks to all who had the patience to copy my qrp signal.

Sept 14 QSOs from JO61VB

Sept 2014: QSOs from JO61VB

DF9NP PLL / simple 10GHz test signal generator

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Dieter, DF9NP offers nice PCBs with VCOs locked to 10MHz precision TCXO. I ordered one with 0.28ppm TCXO and Dieter was so kind to tune one of the VCO to a frequency of 2592.2MHz. Together with a Multiplier x4 made by DG0VE this makes a nice generator that shows up around 10368.8MHz. I connected the both units to a small horn and placed it close to the window. The signal was visible on the websdr screen immediately. The oscillator from Dieter has about 14dBm output while the output buffer amplifier can be switched by connecting one pin to ground. The multiplier has about 200mW output at 10GHz.
During the first test i noticed that the airflow through the open window was changing the frequency of the TCXO slightly. This caused some instability at 10GHz. During a measurement in the lab i saw that the airconditioning was causing a even more significant drift while isolation from the surrounding air results in a very stable signal. Therefore i decided to put the oscillator in a metal can. This also improves the heat dissipation of the linear regulator for the PLL supply voltage.
The pictue shows the test setup close to my window.

10GHz test signal generator

10GHz test signal generator


The screenshot from the Dresden 10GHz WebSDR shows the test signal at the lower end of the scale and the DM0TUD beacon at the upper end. The distance from my location to the WebSDR is about 7km and i have some houses and trees directly in the path.
10GHz testsignal on WebSDR

10GHz testsignal on WebSDR


test signal spectrum at 10GHz

test signal spectrum at 10GHz

2014 May DUR Activity

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This time a completely different setup again.
23cm 15W with Quados, 13cm 1W with double quad element (i had nothing better, sri), 9cm 5W with Wimax-Patch antenna, 6cm with dish (the green one) borrowed from DL4DTU (TNX !), 10GHz/24GHz 5W/130mW with 6cm offset dish (transverters borrowed from DL4DTU).
This time Harald, DG3UH joined and we did a number of QSO on almost all bands. Only 24GHz did not work well with DL4DTU and there was no other station activa on that band.
If i remember correct: 23cm 9QSO, 13cm 5QSO, 9cm 1QSO, 6cm 3QSO, 3cm 1QSO, 1.2cm 0QSO.

DUR201405

DUR201405

10GHz Rainscatter on WebSDR

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Last week i took a screenshot of some RS signal on the local 10GHz WebSDR (http://microwavesdr.hopto.org:8901).
The picture shows the signal of DM0TUD with some strong rainscatter reflection with some doppler offset and frequency spread.
The spread and the shift are caused by reflection at falling raindrops during some local rain.
The clouds where high enough to give also some reflections from the beacons DM0UB (Berlin) and OK0EA (Prague) which can be seen as lines in the waterfall display.
dm0tud_dm0ub_rs_s

once again – DL1DBR rotator control

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My rotator control unit (design by DL1DBR) is more or less finished now.
All the stuff is in the enclosure and working. Items that i needed to solve were:
– deal with some bug in the PCB print were the names for the connectors for Keys and LCD are mixed up ;)
– connecting the KR600 rotator which is 24V AC with end switches which needs two driver PCB in parallel to keep this function
– change the connection of the poti in the rotator unit to measurement voltage over the complete 500 Ohms
– change the software to allow for stopping the motor in the moment the direction key is released (before it stopped only on pressing the OK button)
– changing some libraries to get it compiling in my environment
– deal with the CDC UART (i replaced the CDC done with Attiny2313 by a FTDI UART-USB converter, this works in all environments in contrast to the CDC)
– search for a suitable 24V AC power supply for the motor
– get the DC for the controller working in the environment with the motor (i decided to spend a 2nd trafo for the logic because that was the fastest way to get rid of the interference which disturbed all the resistor measurements)

Rotor Control unit DL1DBR

Rotor Control unit DL1DBR


The following picture shows the inner of the rotator control unit.
Inner of Rotator control unit

Inner of Rotator control unit


Starting with the right upper edge: Thats the 24V AC transformer that supplies the motor of the rotor unit. Below that there is a small black part. Thats the 15V transformer that generates the voltage for the digital part. Using the 24V from the motor supply resulted in crazy measurements due to the strong interference from the motor. At the lower edge you can see the display PCB mounted to the frontside of the enclosure together with the keys. Above there the brown PCB is the main control unit that is driven by a Atmega controller. It gets its supply from the blue PCB on the left edge of the enclosure which is a DC/DC converter that generates about 8.5V out of the voltage from the black transformer. The PCB above the controller PCB is the driver for the motor. Actually its two identical PCBs stacked. The capacitor for the phaseshift of the motor resides in between this stack. The PCBs use each two solid state relais for switching the supply voltage.
For the remote control of the unit i replaced the Attiny CDC implementation by a FTDI USB-UART adapter that is mounted at the left side. Its the silver part there.
In case you have questions… Let me know.

Quisk and CWSkimmer

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CWSkimmer may work under Wine. To connect it to Quisk you can use the Alsa loopback device. The driver needs to be loaded, then start the skimmer.
Set it to softrock (not the IF version !). You may set a LO frequency and activate the telnet server and the remote control via telnet commands.
Set the Alsa loopback interface as soundcard.
Set the skimmer to 48kHz sample rate and start it. The waterfall will start but will not display anything.
Quisk needs to be configured to use the correct loopback soundkart for digital_in and digital_out. If this is ok start quisk and set it to digital iq mode.
You can now adjust the bandwidth to maximum (21kHz) and set the AGC to off and adjust it to a good value.
Now skimmer should show decoded signals within the 21kHz. If the waterfall looks like too strong audio you have most probably a wrong sample rate set in the skimmer.
If you enabled the telnet server you can login with “telnet localhost 7300”. You login with your call and get something like a dx-cluster. The frequency is still relative to the LO frequency. You can now adjust the mid frequency with “skimmer/qsy “. Now the display should be absolute. Remember that its not adjusted automatically if you change the LO in Quisk. Currently its not possible to use skimmer and do CW operation with Quisk in parallel.
Find a screenshot below.

Quisk & CWSkimmer

Quisk & CWSkimmer