I was born in Sinj (Croatia) in 1959, and became ham operator in 1974. I am RF Engineer, with Master's degree in Control Systems (from Uni of Zagreb).
Please QSL via bureau, direct or LOTW (LOTW only on e-mail request from paper logs).
My ham interests are: DX, low bands and CW. I need 2 DXCC countries: Heard Island and Juan De Nova - and hope to complete soon.
Operating from suburs is not much fun, even with good antennas. Urban environment is very noisy, and DX signals at low angle are heavily attenuated.
Good antenna can give you say 10dB gain, and good amplifier another 10dB. Good location can mean 40dB improvement.
I seek dominant locations and setup portable station - with big antennas, amplifier and power generator.
Spiderbeam poles and kites allow me to setup high performance antennas in a very short time.
It takes only 2 hours to setup 3 element vertical yagi for 160M band. This antenna is 95m (312') high, and elements are 81m (266') long.
Portable DX Antenna Evolution
Some locations have poor RF ground, some have many ground obstacles. I wanted massive amount of low angle radiation, independent of location type and ground properties.
1. I started with Ground Plane(GP) antenna - vertical monopole with 4 elevated radials.
2. Vertical Dipole (VD) is 1.5dB better then GP, good at clearing ground obstacles, and less dependant on good RF ground.
3. Elevated VD by 0.5 wavelengths adds 1-3dB, and is even less dependant on ground RF properties.
4. Vertical Yagi (VY) can add 5dB more on top of elevated VD.
5.Bottom feeding to keep heavy bits (coax, balun) low and reduce mechanical loads.
Vertical yagi with bottom feeding is my antenna of choice, 9dB over GP and very independent of ground properties.
Bottom feeding means you keep heavy bits (coax and balun very low). This reduces mechanical loads, and you can use fibreglass poles instead of towers.
Some of my antenna projects are on dropbox, see link: https://www.dropbox.com/sh/bvx2jncb1ny9mbl/AADLuyttl6MXs0IOenOjvAaua?dl=0
Hilltops are often windy places, and I need serious size rotator -like Kenpro 2700. This rural hilltop location has great views of the ocean, and DX signals are often 30dB stronger then at my home.
AL-1500 looks very robust and sleek, with matching tuner MFJ-9982 and external QSK unit.
I use paper log, and send CW by hand - no computer and no microphone. Sending fast CW from car is hard, but I have recently improved mounting for key and can send at 40 WPM now.
I can receive CW as usual, 60 WPM in good coditions and 45 WPM in most conditions. You can send to me very fast, but I can not send too fast from car.
Spiderbeam yagi and 18m mast are used on high bands. Bottom fed vertical yagies are used on low bands.
I fly kite lifted antennas, and have over 50 kites for different wind conditions. Kites enable quick and easy antenna lifting at any location.
I use Spiderbeam poles to complement kites (2x12m, 3x18m, 1x22m and 1x26m).
My antenna is most often 2el vertical halfwave yagi with bottom feed. Using single high support makes it easy to lift and change direction.
I enjoy experimenting with wire antennas, especially bottom feed vertical yagis. Highly unbalanced high impedance feeding is problem with this antenna type.
Reducing feedline radiation is a major challenge. Using high power and directional antennas makes it even harder.
I have developed high performance tuner / transformer,and multilayer choke baluns for bottom feeding.
Lightning protection is also important when flying 120m high antenna from a hilltop. My coax choke baluns are part of protection system.
Other interests : Rugby Union, Matlab, C++ and Embedded Systems.
My favourite team : Jasna and our grandson Sonny.
Example KiteAntenna : bottom fed half wave vertical for 160M band
This vertical is 80m long, radials are not required. Bottom is 16m high, top is 96m high.
Spiderbeam 18m pole holds end fed tuner and coax 16m high. Short fishing rod works very well too.
Kite lifts vertical antoher 80m above spiderbeam pole. This antenna peaks at 10 degrees elevation (over average ground).
Small dot is delta coyne kite used to carry vertical. Antenna wire is copper 0.85mm diameter enameled wire.
Copper loss is only 0.15dB, antenna weighs only 370 grams.
I use second kite to carry reflector,3rd for director. If wind is slow, I run kites in trains ( 2 to 5 kites on one line).
Getting sled kite airborne as night falls.
Home made bottom feed tuner for 30M band (resonant paralel LC with isolation transformer 49:1) for end feeding at 2400 Ohm.
I also make 9:1 balun for 600 Ohm Off-Center-Feed into 75 Ohm coax like RG-6.
Tuner adjusts impedance for coax, but antenna is very asymmetrical.
So, I use at least 2 coax-choke baluns in feedline (multilayer resonant coaxial choke design).
My dogs: Simba and Max
7063976 Last modified: 2016-02-05 19:24:34, 6513 bytes
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