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TRAVELLING WAVE ANTENNA

Multi-band travelling wave antenna for portable operations. Under development


With the view to establish a quick and easy multi-band antenna deployment for portable and camping operations a travelling Wave Antenna with an earth with and 9:1 voltage unun is one possible solution.

Description

 

Figure 1  Multi-band travelling wave antenna with an earth or earth plus counterpoise and 9:1 voltage unun. Configuration includes end termination resistor.

Figure 1  Multi-band travelling wave antenna with an earth or earth plus counterpoise and 9:1 voltage unun. Configuration includes end termination resistor.

 

Figure 2  Multi-band travelling wave antenna with an earth or earth plus counterpoise and 9:1 voltage unun. Alternate configuration includes end 9:1 voltage unun and 50ohm dummy load termination resistor.

Figure 2  Multi-band travelling wave antenna with an earth or earth plus counterpoise and 9:1 voltage unun. Alternate configuration includes end 9:1 voltage unun and 50ohm dummy load termination resistor.

 

 

 

Features

Ground terminated TWAs make very good receiving antennas because the terminations prevent any static build up on the antenna wire, keeping the noise level low.

Construction

The resistor terminator which are used to terminate the far end of each leg of the antenna to ground. . Each Terminator' should have a wattage rating of at least 40% of the transmitter PEP for voice transmissions or 80% for continuous transmission. The amount of power dissipated in the Terminators' depends on the length of the antenna and the frequency in use. The shorter the antenna or lower the frequency, the more the Terminators' become the 'Dummy Load'.

Text  

References 

The ARRL Antenna Book.

http://en.wikipedia.org/wiki/Traveling_wave_antenna

The above radiation plots were produced using MMANA-GAL Antenna Analyser software by JE3HHT, Makoto (Mako) Mori at http://hamsoft.ca/

 

 

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Page last revised 9 May 2013
 

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