QTH: Prague (Praha - the capital of the Czech Republic), locator JO70GC,
My life (briefly):
I was born in 1969, married with my beloved Jolana ( OK1IAW ), we have three children, daughter Elisabeth (1994), in the middle the boy Matej (2000) and the youngest Julie (2006).
I studied radioelectronics at the Czech Technical University Prague, in 1994 I received MSc ( in czech Ing.), in 2002 I have received Ph.D. degree, my doctoral thesis deals with microwave vector measurement systems. I am specialized mainly to the high frequency circuit and antenna design, different measurement techniques and communication systems.
I am working since 1997 as a microwave designer in a company named ALCOMA ( http://www.alcoma.cz ), a leading producer of microwave links in the Czech Republic. I am designing and constructing microwave circuits and blocks for our microwave relay links up to 90GHz, such as LNBs, power amps, oscillators, mixers, synthesizers and so on. What more can you wish, if you can do something, what you have years studied, you like it, it is your hobby and you are paid for it? Let us hope it will not bore me after some time!
I have to add that in our company, there are working more other hams, such as OK1PRU, OK1FRU, OK1XZA, OK1FPC a good community indeed!! We have a club station OK1KRU. Due to the lack of time we are not so active as we want, but maybe in the future we will find some more time to our club team activity and improve our activity on the bands, but I do not believe to that too much because year after year we are more and more busy with a less free time. Do you know that feeling too?
I was and I am still a very active person with a lots of hobbies and interests. From my childhood I have collected historical post stamps (mostly Europe up to 1945, Czechoslovakia 1918-1938). I like fishing, mainly using spinning. One of my other strong hobbies is the music. From my childhood I learned to play the piano and a trumpet at a music school, than I tried to learn a little bit country guitar and contrabass. I am playing dixieland, rock and roll and blues with a different bands. The very active years with music I spent when I have played the trumpet with the band BLUESBERRY. You can find my trumpet barks on two CDs of this band too. I have composed some small music for TV advertisements, it was nothing bombastic, but an interesting work and really other world experience for radio engineer. Now I am playing trumpet with a band called WOODEN SHOES, another band from the Hanspaulka, a known Prague quarter, the nest of the Czech blues music. We are playing not often, so every our concert we play from all of our hearts and it is a great feeling. Some time ago I have joined a next friendly "bigband" group OOZ, imagine brass and saxophone section with seven musicians!!! I use to play dixieland too on various jam sessions in Prague too.
All of those bands are sure not on the top 40, but I like it very much to play and it is a great fun between musicians, very different experience and a counterweight to my work. I am sure not a good trumpet player, I am never satisfied with my sound and the tone range. The trumpet is a very ungrateful instrument, it needs regular training every day. Without the training the trumpet behaves as a pipe full of crow croaking, but sometimes when it finally sounds good you can think you are touching the music...... I hope Mr. Louis Armstrong is not looking at me!
An another big hobby is a motorcycling. The sound of slow
running four stroke engine is the best music for me, altough
they were very rare in Czechoslovakia. I have begun
with a JAWA 21 (50ccm), it was my 1st workhorse which I have got
in 15 years age after getting my first driving licence. In the
best years I was able to ride on it about 3500 km per
year!!! A reliable two-stroke machine (as the most Czech
ones) for a young boy indeed with the 4 HP engine!
Few years before I had a great luck with buying a "veteran" bike with a family history. It was my father's bike in his younghood ( original picture with my father on it in 1951) ) and he sold it around 1955. After 50 years of working in foreign hands I have bought (with a great luck and diplomacy of my father) the same machine back (from the same person to whom it was in 1955 sold) after 50 years again. Looking terrible, rusty, but quite complete (see the gallery). After one year of exhausting reconstruction it is looking like a motorcycle again (me and bike in 2004) . It is CZ 125 T (in Czech correctly written ČZ 125T as a shortage of name of the factory Česká Zbrojovka - Czech Armament Factory) a 125ccm hardtail motorcycle from 1949. It is a quite legendary bike which was even exported to USA too and sold under the Indian brand as Indian CZ 125, I have read that due to its low weight it was used by US border patrol on the mexican border too !! Some pictures will be sure added (see gallery). For people who interests more in this theme I recommend a site www.motomagazin.cz, where lots of information about Czech vintage motorcycles can be found.
I am thinking a lot about a bigger chopper too, for some more comfortable rides, but it is a question when this dream will came true due to some other reasons and priorities.
It seems that the motto "oldies are goldies" is still valid in my life. We are restoring (my father and partly me) now our another vintage machine - a cabriolet DKW F7 from 1938. We posses it from the sixties still in our family, it was my father's car too, then it was used by my grandpa up to the 1975, when it was put aside and waiting for better days. It has driven in our services more than 400 000km, a distance from Earth to Moon.
The last and strongest hobby (but not least) is the radio and
radioelectronics (more written down).
I am not sure if my beautiful wife and our children are a true hobby, but it is sure an activity, which spends sure a part of my free time too.
My own HAM activity:
A story how I got to radioelectronics is quite long and it will full a single paragraph (maybe I will publish it in the future). The present is below.
I am interested mostly in VHF and UHF band, but I do not forget to shortwaves too. Due to the QTH which is placed in the eastern part of the capital city Prague, I had to focus to activities which can be done from the average QTH, so I have decided to work on the satellites. I have tried sats such as RSs, FO-20, FO-29, AO-10 in SSB. I have prepared and tested equipment for AO-40. More about my AO-40 activities and constructions you can find here. Unfortunately due to the AO-40 failure the dish for 13cm on the roof is silent, up to the start of P3-E I replaced the 13cm convertor with a feed for 23cm for some local activities, but I am ready to reinstall it back again immediately, when some new SSB microwave bird with 13cm appear again.
From the May 2005 (due to the administrative changes in Czech HAM licence classes) I am active on shortwaves too, although the location is not very ideal, due to the QRM from the capital city. The greatest source of QRM here is the phase control of two lift engines in our house. Although it was correctly installed, with all necessary filtering, my antennas in 10m distance are receiving it strongly, from 1.6-10MHz it gives broad QRM above S9.
My ham equipment:
All begun on CB, with a legendary President HR-2510 for 10m, than different homebrew transvertors for 2m, than FT-780R for 70cm. After that came the Icom IC706 MK 1. I have built a homebrew 100W PA with Dual VMOS transistor BLF278 (PHILIPS) from radio scrap. My antenna is 6el. yagi in horizontal polarization for 2m with GaAs FET preamplifier (homebrew too, using russian military power GaAs FET for 12GHz/0.5W AP602D with ultra high IP and F=0.8dB on 144MHz. This was a need due to a presence of local TV and radio strong signals and diverse radio smog of the capital city around my QTH). The signals from CCIR FM radio and UHF TV from local main Prague transmitter with 100kW transmitted power reaches about -10dBm on my antenna output!!!!!
For 70cm I am using an old Yaesu FT-780R (15W out) with 17el. F9FT antenna in horizontal polarization. I am planning to built some preamp and PA for 70cm, transvertor for 23cm and higher, but nobody knows, when I find some time for it.
For 3cm I have adapted some components used in our 10GHz microwave link to work as a SSB transvertor. As the local oscillator I am using phase locked DRO, which is controlled by use of DDS synthesizer. It works very good and the frequency accuracy on 10GHz can be set in a Hz range. I am having now only 100mW, but the all components for 10W PA are waiting in my drawer at work for better free times.
The IC-706 and the FT-780R were sold, as a multiband replacement the KENWOOD TS-790E (2m, 70cm, 23cm allmode) came home. Having now a triband with sat capabilities is better, its basic power is higher too. I have to say that I like more the classical radios with thousands of knobs than a modern radios (IC-706) with thousands of menus. Now I am planning to add T/R switching, adapt the radio to be able to work with PA and transvertors for microwaves. Trying to be active from time to time, due to the failure of AO-40 loosing enthusiasm, let us hope the future will be brighter.
For the shortwaves a KENWOOD TS-450S was
bought and on the roof a triband mini-beam MINI 2000 from ZX
Yagi was added and a G5RV (modified to ZS6BKW type) wire
antenna for the lower bands. On our house it is a maximum,
what I can allow. The QTH is good (high), but I have terrible
problems with interference from speed control (triac frequency
convertor) of the elevator engines and different industrial
noises of the city around me. I am limited too in transmitting
power due to the proximity of 100 flats of my neighborrows to
my antenna. Causing TVI or EMI will be a very unpleasant
problem for me.
For satellite traffic I have adapted my old rotator (Commander
2000 similar as Kenpro) for the computer control. The elevation
control is made by use of standard satellite dish actuator
(computer controlled too), a much cheaper solution in comparison
to other elevation rotators. My PC is equipped with A/D and D/A
card and digital I/O card (now using Labjack D12) and for
the whole tracking system I have programmed a special control
software in Delphi (Pascal), which can track the satellite
automatically in azimuth and elevation by use of DDE
collaboration with the tracking program or similar.
Everything is made in a realtime, now working under XPs. Because
all could work automatically, I can fully concentrate on
QSOs, because the antennas are quite sharp and manual tracing is
not very comfortable and easy. I am curious to see, how it will
be with the 1.8m dish on 13cm and on 3cm.
Special page devoted to my AO-40 activities (inclusive the MMDS convertor modifications) you can find here.
After moving into a new flat (13. floor!!!) all antennas are slowly growing again on the roof!!
I am sometimes active too during contests from
home or portable QTH on 2m, 70cm, 23cm or on 3cm somewhere in
the mountains under my callsign or our club callsign OK1KRU.
In my free time ( which is year after year (and child
after child) more and more limited ) I like to design and
construct different HF circuits. I have constructed few
transvertors, PAs, preamps and measurement equipment for RF,
but there is not so much time as before and to be honest,
sometimes I am so tired from the work, that a look to a
soldering iron makes me qualm. Iagree that Internet and
virtuality of its word is not a good thing, it is a time
I was involved in some antenna development for 2.4GHz and 5.6GHz, a little bit more about my WIFI activities as a result of some antenna development you can find here. (in the future).
The KENWOOD TS-450S
after its known failure with DDS ICs (YM6631) was replaced by the
TS-870S. The TS-450S after long search for last DDS ICs was
succesfully repaired and I use it by my parents now.
A new shortwave antenna was bought- it
is multiband rotary dipole from ECO Antenne for 12-17-40 m (catalogue COD 042) I have bought
it via Ebay IK2GAO. The only positive thing I can say it was not
expensive (around 200 EUR). Some of the tubing has wrong diameter,
so I had to buy the correct tubes here to complete the
antenna. There was very poor brief manual in Italian only,
the manufacture was not able to send the english version of it.
Their support is not working even by more email requests, although
it was clear, that they made something wrong, they are not
responding. The antenna could not be adjusted properly on 17m, the
resonance is sitting about 17.7MHz (outside of
specification) with SWR on 18MHz above 2 without possibility
to adjust it, on 40m and 12m it works. Very bad experience with
this manufacture, I do not recommend it or you must be prepared to
finalize the antenna by yourself. The antenna is quite big (above
13m length) and has a quite high vertical deflection, not seen on
the manufacutre poor pictures, so I have guided it with
nylon ropes to be sure, it withstands the winds here.
The picture of this antenna on the
mast you can see in the gallery for better understanding of its
size. I have here the SWR graphs measured on directional
bridge after installation and tunning you can find here..
If you found something
interesting, do not hesitate and ask me (by mail above).
See you later on the air! 73s!
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A small picture gallery of my family and
ham activities, by clicking on the thumbnails you can get the
enlarged pictures, best viewed in 800x600 or higher.
Some of the pictures are quite big, be patient or do not download them with slow Internet connection!!
That is me OK1VAW.
This is my wife Jolana OK1IAW. You can see the question in her eyes: Why I have married you, Vojtech?
My daughter Alzbeta in
the age of 5, picture taken in cockpit of TU-154 airplane
somewhere over Greece. It was in the peacefull times when it was
allowed during the flight to visit the captain in the pilot
A big girl Alzbeta after some years later. The time is running.....
My son Matej in his childhood..
Family holiday idyll in
Croatia, my mother, my wife and me.
My father on the CZ-125T motorcycle in
My father now.
Our restored DKW and my father.
If you see me comming better step a side!! .My CZ-125T after
reconstruction and me, both ready for a ride..
3,2,1 GO!!! Me and my brave wife on tandem in action in the
Klecanska Veteran Rallye.
Our Julie tests the Harley. She loves the
motorcycles most of all, maybe some familly ilness?
That is me, taken around 1994, in my old ham-shack in the old flat, before my wings were space cut by marriage. Sweet university times!! Left you can see a russian spectrum analyzer to 40GHz!!!!, a russian oscilloscope to 250 MHz, a signal generator 2MHz -1GHz Ferisol LF 301 and a counter. The red box is my diploma thesis result: PC controlled sweeper 1MHz-1GHz. The time is running.....
Three pictures of my old flat antenna farm.
6 element Yagi on 2m in horizontal, 17 elements on 70cm in
horizontal and multiband harmonic log-periodic antenna "Fish
bone" for 2m, 70cm and 23cm. A very interesting construction
with good performance. You can see different elevations of the
whole system, controlled by satellite super-jack. Easy and
reliable. All of that is history now.
Three pictures of my new mast in the first arrangement. A new construction, more place for antennas. The same antennas as above, but 90cm prime focus dish for AO-40 added. Still in testing, 1.8m grid dish as a replacement for 90cm is waiting, thinking about adding something for 10GHz too, but it waits for a better weather and a multiband feedhorn.
The new antenna for shortwaves was added.
MINI-2000 minibeam for 14/21/28 MHz. It seems not to be very
ideal among the other antennas, but seems to be working
successfully. There is part of the city horizon visible,
the 13.th floor gives a free 360° view without obstacles,
good for the satellites.
For other bands a wire doublet G5RV modified to ZS6BKW was used with tuner for other bands.
The ECO rotary multiband dipole was
installed. Although is close to MINI-2000, there seems to
be not too much coupling between them due to different used
bands (maybe except undocumented resonance of dipole on 10m
too). You can see it is sure not small, due to its size it is
able to easy turn the rotator (it has no brake) in stronger wind
as a weathercock .
For "high power"
lovers. One of my weekend project maybe 15 years ago, a
power amplifier with a FET BLF278A constructed for 2m (for the
IC706), which after first adjustment works so good, that I have
no itch to rebuild it, although it looks very wild. It will
probably last for ever, as Germans said "bombenfest und
idiotensicher". Bipolars-never more!! More pictures of
that project find here.
my english, trying to do my best!
Last changes 5. August 2010
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