Yagi is finished now. I have to build the mast clamp. Due to Mr. Murphy the centre of gravity is right below D1…
4El DK7ZB for 10m in the attic
4El 10m DK7ZB antenna without clamp
10m Yagi progress
Category Archives: Antenna
Habemus Dipolum
Finished the dipole for my 4El DK7ZB Yagi for 28MHz.
Hope i get the rest finished until Jan. 8th ;)
28MHz Dipole
10/24GHz feedhorn by W1GHZ
From Paul, W1GHZ i got a dual band feedhorn for offset dishes for the 10GHz and 24GHz band. It was somehow funny to explain the customs officer what it is ;) Now it is my turn to complete the station and get on air. I am excited.
dual band feedhorn, 10G/24G
dual band feedhorn, top view
New antenna (1.5m mesh dish)
Yesterday i got my new 1.5m mesh dish (Drahtgitterspiegel) from Funktechnik Liebal http://www.funktechnik-liebal.de/. It can be splitted into two parts for transport.
The 3-band feed i will get soon supports 23cm/13cm/9cm. So there is room for extending the portable rig.
The foto shows the dish with a 13cm feed.
1.5m GIPA dish from Gert Liebal, DG0CN
Quados4 23cm dimensions
On special request here the dimensions i used for my quados4 antenna. For further information please see the pages of YU1AW.
It has to be mentioned that the dimensions appear to be a bit too long which can be seen from the measurement below.
This is although the element was manufactured of 2mm diameter wire.
dimensions of my quados4 antenna for 23cm
23cm Quados4 antenna
Some time ago YU1AW published some documentation about his experiments and simulations with stacked quad elements for 13cm. He optimized the stacked quad design by changing the distances of the quad elements by using parallel wires in between. He showed that these antennas show some improvements against traditionally stacked bi-quad elements were the distance is too low. He published data for 4 quad element antennas (Quados4), such with 6 quad elements and with 8 elements.
DF9IC published some results with the 8 quad element version recalculated for 23cm. This year DH1FM built two of these Quados 8 antennas for 23cm and used it successfully in contest operation.
To get a feeling of this antenna type i built the Quados4 antenna for 23cm. A big problem for me was to get it somehow mechanically stable. The accuracy of the quarter lambda transformer and the big distance between the wires at the feedpoint showed some difficulties as well. In the end the antenna seems to work and brings close to 6dB better results than my biquad antenna. But in fact it seems that the distance between the reflector and the antenna element is still too large because it improves if the end elements are bent towards the reflector.
Find some pictures below.
Quados4 input matching measurement
Quados4 antenna test construction
For the future i will try to build a 2x Quados4, means two of the elements above side by side.