Do It Yourself
Accessories
Portable Antenna Tuner
l like QRP operate at the hill top with a random wire. It is light weight, very cheap price, save more power and very easy to bring. But if we need to use the random wire for all HF and 6m bands operation, we should series a antenna tuner bewteen our equipments for the best impedance and power matching. In this project, it can match the load to 50ohms if the length of the random wire are longer or shorter than its 1/4 wavelength. Let's go to see the following simulations, specifications and testing result.
¡@
 |
 |
| Outlook | Back Cabinet |
¡@
 |
 |
| Inside the case | PCB |
¡@
Schematic Diagram in PDF format
PCB Layout in PDF format
¡@
Specifications and Details :
| a)
¡@ |
Input
terminal
¡@ |
:
¡@ |
SO-239
(M-type)
¡@ |
|||
| b)
¡@ |
Output
terminal
¡@ |
:
¡@ |
SO-239
(M-type) and Red, Black Banana Socket. (Selectable)
¡@ |
|||
| c)
¡@ |
Tuning range of variable inductor | :
¡@ |
Main
: 0pF to 1n1F step 100pF. Fine : 4pF to 100pF.
¡@ |
|||
| d)
¡@ |
Tuning
range of variable inductor
¡@ |
:
¡@ |
Main
: 0uH to 33uH step 3uH. Fine
: 50nH, 100nH, 200nH, 300nH, 400nH, 500nH, 600nH, 800nH, 1uH, 1u5H, 2uH,
2u5H.
¡@ |
|||
| e)
¡@ |
Power
handling
¡@ |
:
¡@ |
50W FM and 100W SSB continuous and 100W FM for not more than 10 seconds. | |||
| f)
¡@ |
Matching
range
¡@ |
:
¡@ |
For 7MHz to 54MHz, 10ohms < Z load < 3500ohms. For 3.5MHz, 20ohms < Z load < 3500ohms. For 1.8MHz, 50ohms < Z load < 2500ohms.¡@ | |||
| g) | Simulation result | : |
Z load |
10 ohms |
||
| For Z load = 10ohms |
Frequency |
L |
C |
Result |
||
| ? |
1.8MHz |
1.8uH |
3.5nF |
|
||
| ? |
3.5MHz |
908.3nH |
1.8nF |
|
||
|
7MHz |
454.1nH |
910.2pF |
|
|||
|
10MHz |
319.5nH |
635.1pF |
|
|||
|
14MHz |
228.2nH |
453.7pF |
|
|||
|
18MHz |
177.5nH |
351.7pF |
|
|||
21MHz |
152.8nH |
300.8pF |
|
|||
|
24MHz |
132.5nH |
265.5pF |
|
|||
|
28MHz |
113.5nH |
227.5pF |
|
|||
|
30MHz |
106.5nH |
211.7pF |
|
|||
|
50MHz |
63.9nH |
126.6pF |
|
|||
| Simulation result | : |
Z load |
25 ohms |
|||
| For Z load = 25ohms |
Frequency |
L |
C |
Result |
||
| ? |
1.8MHz |
2.2uH |
1.8nF |
|
||
|
3.5MHz |
1.1uH |
909.4pF |
|
|||
|
7MHz |
573.9nH |
454.7pF |
|
|||
|
10MHz |
401.8nH |
318.3pF |
|
|||
|
14MHz |
285.1nH |
227.4pF |
|
|||
|
18MHz |
221.8nH |
176.8pF |
|
|||
|
21MHz |
189.2nH |
150.6pF |
|
|||
|
24MHz |
166.3nH |
132.6pF |
|
|||
|
28MHz |
143.5nH |
113.7pF |
|
|||
|
30MHz |
131.5nH |
106.1pF |
|
|||
|
50MHz |
79.8nH |
63.7pF |
|
|||
| Simulation result | : |
Z load |
100 ohms |
|||
| For Z load = 100ohms |
Frequency |
L |
C |
Result |
||
|
1.8MHz |
4.4uH |
882.7pF |
|
|||
|
3.5MHz |
2.3uH |
456.2pF |
|
|||
|
7MHz |
1.1uH |
227.0pF |
|
|||
|
10MHz |
795.7nH |
157.9pF |
|
|||
|
14MHz |
572.1nH |
113.5pF |
|
|||
|
18MHz |
442.1nH |
87.7pF |
|
|||
|
21MHz |
378.9nH |
76.0pF |
|
|||
|
24MHz |
331.6nH |
65.8pF |
|
|||
|
28MHz |
284.2nH |
56.4pF |
|
|||
|
30MHz |
265.2nH |
52.6pF |
|
|||
|
50MHz |
159.2nH |
31.9pF |
|
|||
| Simulation result | : |
Z load |
3500 ohms |
|||
| For Z load = 3500ohms |
Frequency |
L |
C |
Result |
||
| ? |
1.8MHz |
37.4uH |
206.0pF |
|
||
|
3.5MHz |
19.2uH |
106.0pF |
|
|||
|
7MHz |
9.6uH |
53.0pF |
|
|||
|
10MHz |
6.7uH |
37.1pF |
|
|||
|
14MHz |
4.7uH |
27.0pF |
|
|||
|
18MHz |
3.6uH |
21.3pF |
|
|||
|
21MHz |
3.2uH |
18.0pF |
|
|||
|
24MHz |
2.8uH |
15.7pF |
|
|||
|
28MHz |
2,4uH |
13.5pF |
|
|||
|
30MHz |
2.2uH |
12.6pF |
|
|||
|
50MHz |
1.3uH |
7.5pF |
|
|||
? --- means it cannot cover these regions but I think 1.8MHz and 3.5MHz antennas are impossible at 10 ohms and 25ohms because the length of the antennas will very very long. For 1.8MHz 3500ohms, the maximum inductance of my tuner is 35.5uH. The simulation result is 37.4uH. We can increase the antenna length for less inductance value.
