DARC 10m Contest

Posted on January 11, 2015 by mario

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.

U02 DDS, by DJ0ABR

Posted on December 18, 2014 by mario

For some tests with WSPR i purchased a DDS PCB from Kurt DJ0ABR. The PCB comes with most parts assembled and you just need to solder some easy stuff as well as mount it into an enclosure. There is a microcontroller that interfaces with a PC or operates the DDS alone. It can be used as synthesizer for AM FM, as a wobbler unit as well as beacon for WSPR, CW and DSTAR. Frequency range is from medium wave to 160MHz.

Edit:

Today i added the GPS receiver and connected the DDS to a Outbacker 1899 antenna placed on the heating inside the room. During the sunset some stations received my 50mW signal on 20m.

wsprnet_20m_50mW

[The list is a screenshot from WSPRNET.org]

Marconi Memorial Contest 2014

Posted on November 4, 2014 by mario

Another contest from my home location in the Elbe valley this year. Again i used the 2m DK7ZB Quadlong antenna. Its doing surprisingly well. But this time i had 200W of output. Direction southeast was pretty good again. Now ODX was 9A4V. Thanks for the good ears down there ! Also other directions (except east) were working okay. That was mainly due to the fact that i used the reversebeacon network to gather spots generated by DJ3AK. Many thanks for that as well. Also DJ5AM (very close to my location) ran a skimmer which generated a few useful spots for me. My original plan was to run my own skimmer but that was not working due to setup issues. But the receiver of DJ3AK was really useful. Getting spot into the log-window, click to the call which tunes the TRX to the frequency and takes the call over. The macro and keyboard keyer functionality did the rest ;) East direction does not work because i am located at the east side of the Elbe valley and the hill is going up too high to get over there.

Marconi_2014_JO61VB

The map nicely shows the directions of the valley i can operate through with some exceptions of other stations from different directions.
A nice one was F8KID and HB9FAB, HB9TYU as well as PA4VHF and OZ6OL.

Tiny Sequence control unit (WIP)

Posted on October 15, 2014 by mario

Thats a simple sequence control unit for transverters etc. ON a double layer PCB. The design was eine with the open source tool KiCAD. Its made around a attiny2313 and features a highside switch, a lowside switch as well as a uln2003 driver. In addition further sensors can be connected via I2C or SPI. The software is not finished. More information will follow.

Hex-Quadlong for 70cm

Posted on October 6, 2014 by mario

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 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

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

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

70cm October 14 Reg1

Posted on October 5, 2014 by mario

28 QSO with 20W and Hex-Quadlong antenna i built just before. I just wanted to try the antenna. Just few time for operation.

Hex-Quadlong 70cm

ODX was HA5KDQ via random. Impressive good ears there ;)

70cm QSO distribution

Decent results Saturday evening. Better results Sunday because more stations did CW.
The reason for using this antenna is the possibility to mount it at the top of a fibre mast installed at the balcony.

VHF contest from home

Posted on September 8, 2014 by mario

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 2014: QSOs from JO61VB

DF9NP PLL / simple 10GHz test signal generator

Posted on June 22, 2014 by mario

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

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

test signal spectrum at 10GHz

62dB step attenuator by SV1AFN

Posted on June 4, 2014 by mario

A nice page and a source of some good projects is the one of Makis, SV1AFN.
The page can be found at sv1afn.com.
I purchased the step attenuator control module with 2x 32dB attenuator blocks. The both blocks can either be used in parallel always set to the same attenuation level or in series allowing a maximum attenuation range of about 62dB.
Build into a small enclosure it gives a really nice unit for your daily usage.

sv1afn step attenuator – front

sv1afn step attenuator – rear

2014 May DUR Activity

Posted on May 19, 2014 by mario

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

Rauschfunk

V-U-SHF / SDR / DV and more by Mario, DH5YM