I have got a radio telephone DAEWOO DWP-5000 working in a range 900-MHz at the radio market in Kiev (see Figure DAEWOO DWP-5000). I checked up the phone with its antennas. I could reach only 300- 350 meters when the phone saw the radio base. I need 2 kms communication range. I decided to increase the communication range of my radio phone by using an effective antenna. By the way, the antenna placed at the base was made as a steel spiral, located into a rubber tube (see photo Base Antenna). The length of the antenna was 4 centimeters.

So, for my phone I decided to use well known in the former USSR so-called antenna Harchenko. The antenna has a wide range and can work at the range of 886- 931- MHz with a low SWR.

Petr Gritcay, US1REO

Base Antenna

DAEWOO DWP-5000

Do not forget, transmitting and receiving frequencies differ each other to 45- MHz at the 900- MHz phones. Antenna Harchenko was calculated by Free Antenna Simulation Program MMANA. Parameters of the antenna are shown below. Left diagram is a section of the volumetric diagram directivity of plane X-Y at a zenith corner of the maximum radiation.

The right diagram is section of the volumetric diagram directivity of plane X- Z. Also at the right down corner of the pictures is a table with antenna impedance. (see Figures: Schematic of the Antenna, Antenna Z, Antenna SWR, Antenna Pattern)

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