antentopSince2 July

Ham Spirit
Old computer's PSU gives useful parts for antennas
Free Choice

 

 

Free Antentop Amateur Open Book
Antentop Album
Antentop Survey

 

 

 

Antentop is FREE e-magazine devoted to Antennas and Amateur Radio an

Special page devoted to

Old computer's PSU gives useful parts for antennas

Custom Search

 

ANTENTOP- 02- 2003, # 003  

Old computer's PSU

 

Old computer's PSU gives useful parts for antennas

 

Igor Grigorov, RK3ZK

 Continue from ANTENTOP 01- 2003, #002

 

 

An autotransformer

 

AT-33T transformer works satisfactorily in connection shown in Fig. 1. It is an autotransformer connection. Mind, the secondary winding must be connected to the primary one at the right phase (A or B to C).

 

The experiment shows the right connection. Data for

the RF autotransformer are shown in Tab. 1- 3. Tab. 1 shows data for the RF autotransformer while this one is loaded to 300 Ohms. Tab. 2 shows data for the RF autotransformer while this one is loaded to 450 Ohms. Tab. 3 shows data for the RF autotransformer while this one is loaded to 600 Ohms. The autotransformer has rather big input resistance on ranges of 160 and 80 meters therefore values of a VSWR relative to 75 Ohms are shown in these tables.

 

 

An autotransformer

 

Table 1 RF- autotransformer loaded to 300 Ohms

 

Frequency, MHz

 

 

1.9

 

3.7

 

7.1

 

10.1

 

 

14.2

 

Input resistance,

Ohms

 

 

 

80

 

 

60

 

 

45

 

 

40

 

 

35

 

VSWR   relative to 50 Ohms

 

 

 

1:1.53

 

 

1:1.15

 

 

1:1.16

 

 

1:1.31

 

 

 

1:1.49

 

VSWR   relative to 75 Ohms

 

 

 

1:1.07

 

 

1:1.25

 

 

1:1.67

 

 

1:1.88

 

 

1:2.15

 

Efficiency, %

 

 

76

 

 

62

 

46

 

28

 

8

 

 

 

www.antentop.org

Page 65

 

65 66 67 68 69 70 71 72 73 74 75 76 77

 

 

 

QRP Transceivers and PA from Accessible Parts IP for QRP Antentop Book Antentop Printed and e- magazines
 


 

 

Just for Fun:

Map IP Address
Powered byIP2Location.com

Thanks for your time!

Last Updated:

January 4, 2017 20:19

Antentop Home Page

Free Antentop Open Book