Welcome on the homepage of Reto, HB9TMQ webpage updated 2004_10_08 my rig Yaesu FT-897 with Antennatuner LDG AT-897 and Headset Nivico STH-10. I often work on the 20m-Band (14 MHz) international in SSB, locally you can reach me sometimes on the 2m-Band (145.500 MHz) or on the 70cm-Band (Relais Pilatus, 438.800 MHz). My homebrew 20m-Dipol antenna. The Balun was built using material out of an old PC power supply. (see below).   As a Programmer on one side and as a Radioamateur (HB9TMQ) on the other side i found in the WLan-Environment an interesting field for my weekend projects. These projects all have the goal to be very simple, cheap and effective. Waveguide Playing games or chatting in the neighbourhood Lan is fun. Here you see the Prototype built using an old plastic water tube, aluminium foil and other (no-cost) material. Used measures were: A= 40 mm, B= 31 mm, D= 110 mm (inside!!). C1= 121 mm, C2= 242 mm. C2-Type Prototype. View inside of the final C1-Type Waveguide. Final C1 and C2-Type Waveguide and Antenna. simple reflector on the Access-Point side. Some think paper, some aluminium foil, some tapes, 5 minutes.   Helix (helical antenna) Used measures were: D= 58 mm, L1= 340 mm, L2= 33 mm. This antenna is still untested, so i might have to change some of the parameters. Old Paper Tube for the boom, old power cable (ca. 600 mm, copper with 1,5 mm2 diameter), old CD-Rom as reflector, empty Dogfood-Aluminium-Package for the capsula, some screws and a piece of wood as constructional element, some old coaxial cable. The only thing i bought was the SMA-plug. What you need else is: some time (ca. 2 h), hot glue, and tools like screw driver etc.   Sperrtopf (what's the name of this in english?) In Funk , a german Hamradio Magazine (from 3/2003, 6/2003 and 8/2004) i found the articles of Klaus Böttcher (DJ3RW) about this kind of antenna built from old and empty beer cans, catfood-cans etc. These were designed for 145MHz (2m-Band), 435 MHz (70 cm-Band) resp. 1,25 GHz (23 cm-Band). I wanted to use this kind of antenna also for the WLan-environment, so i calculated the parameters for 2,45 GHz (12,4 cm-Band, WLAN) and came to the result below. Design measures: D= 38 mm, B= 30 mm. Depending on the thickness 'C' of the used radiating element, it's length 'A' has to be adapted. Using C= 1 mm, A= ca. 60 mm, with C= 3 mm a value for A= ca. 53 mm results (see shortening factors). The radiating element thus should be dimensioned sligthly longer so that you can shorten it to resonance with the help of the 'Cut-and-Try'-technique. However: too much of 'Cut' means: play it again, Sam. This Design is untested to the fact that up to now i could not find a can or other material with corresponding measures.   Measuring Picture shows a Quad Loop for measuring.