ANTENTOP- 02- 2003, # 003

Bottle Antenna for 145 MHz

By Sergey Mironov, RA1TW

Any amateur can do the antenna during one hour. To do the antenna takes a half of hour and to tune the antenna also takes a half of hour. So, do not waste time and go to make the Bottle Antenna!

 At first take a look at schematic of the Bottle Antenna (Figure 1).

 Specification:

1.                Dielectric plate, approximately of 80x250-mm.

 2.                Vibrator, (5/8)lambda

3.                Matching spool

 4. Tinned plate, approximately of 25x35-mm.

 5. Counterpoises, (1/4)lambda

 6. Stud, washers, screw-nuts

 7. Coaxial cable

 How to do it

1.              Take Dielectric plate (1) and install Vibrator (2) on the plate. Use clamps or hard wire for this.

Bottle Antenna

Side view

At 145 MHz the vibrator takes the length 1270-mm at the diameter of the vibrator 4...5-mm, and 1200 m at the diameter of the vibrator 10...14-mm.

 2.              Install Tinned plate (4) on the Dielectric plate. Use Stud, washers, screw - nuts (6).

 3.             Do Matching spool (3). The spool has 9 turns of 1.5...2.5-mm diameter (# 14- 10 AWG) copper or silvered plate wire. ID of the spool is 15...18-mm, RA1TW use to old markers as a form for the spools. Length of the spool is 34-mm.

 4.              Install the Matching spool on the Dielectric plate. For doing this, the upper end of the spool is fixed to the Vibrator and the down end of the spool is fixed to the Tinned plate. Use solder or fix the ends with the help of screws.

Top view

Figure 1

5.              Do counterpoises. Two 105-cm lengths of copper or aluminum wire of 4...6-mm (# 2...6 AWG) are bended as a Greek letter OMEGA looks (see Figure 2).

Figure 2. Counterpoises

www.antentop.org

Page 40