Shunt Fed Tower Or If You Have a 50- to 60-Foot Tower with Something on Top, Here’s One Way You Can Get on 160M

My Situation City Lot Tribander for 10, 15, and 20M Full-wave Delta Loop for 40M What to do for 160M?

Use Existing Tower http://www.qsl.net/w9rb/webdoc9.htm

Why a Vertical? Low take-off angle for DX Not a “space-saving” antenna Needs radials – the more the better Real World - 16 radials MINIMUM Ten 10-foot radials better than one 100-foot

Construction Two wires 18 inches apart – fat conductor Inside wire 3 feet from tower Gamma section as long as possible Weather-proof plastic box at base

EZNEC+ Version 5.0 f=1.825 MHz Z=27.59 + j556 Model EZNEC+ Version 5.0 f=1.825 MHz Z=27.59 + j556

--------------- SOURCE DATA --------------- Frequency = 1.825 MHz EZNEC+ ver. 5.0 160M Shunt Fed 60Ft Tower --------------- SOURCE DATA --------------- Frequency = 1.825 MHz Source 1 Voltage = 556.7 V at 87.16 deg. Current = 1 A at 0.0 deg. Impedance = 27.59 + J 556 ohms Power = 27.59 watts SWR (50 ohm system) > 100

160M Shunt Fed 60-Foot Tower

Autek Research RX VECTOR ANALYST Model VA1 f=1.825 MHz Z=440 + j300 Measured Autek Research RX VECTOR ANALYST Model VA1 f=1.825 MHz Z=440 + j300

http://www.circuitsage.com/matching/matcher2.html L = 15 uH C = 558 pF Matching Network http://www.circuitsage.com/matching/matcher2.html L = 15 uH C = 558 pF

Source --------- L = 15 uH ----------- Load | C = 558 pF | Gnd Matching Network Source --------- L = 15 uH ----------- Load | C = 558 pF | Gnd

Works okay for transmit Not so great for receive On The Air Works okay for transmit Not so great for receive

Possible Problem Rotor in tower – controller may not be happy Solution disconnect rotator control cable before transmitting