Coaxial cables are the cables meant for radio
frequency and have two conductors in the same axis hence called
coaxial cables. The inner conductor
Construction :-
Inner Conductor – The conductor consists of solid or
multi strand copper wires. This fine strands are twisted
to form the joint free conductor. Depending on the specifications
the form of conductor is varied i.e.
- Plain copper conductor
- Tinned copper conductor
- Silver plated copper conductor
- Copper coated steel wires
The above conductors are provided in accordance to the resistivity,
tensile strength, conductivity etc.
Di-electric :-
The specified conductor is insulated with
insulation material having no air bubbles or no air films
and should exactly
maintained the centre of the conductor. Generally applied
insulation material are …
- Solid polythene
- Semi Solid or Foamed polythene
- Synthetic Rubber
- PTFE
Outer Conductor :-
The conductor laid in common axis with central conductor
is called the shield which is provided by way of lapping
or cross braiding. The shield should not have any break in
less than 300 mm. The outer conductor consists of the following
material as per the design specifications.
- Annealed bare copper.
- Annealed Tinned Copper.
- Silver Platted Copper.
Outer Sheath :-
Suitable grade of PVC Compound . PTFE sheath for PTFE Coaxial cables.
Quality Check :-
A series of tests are conducted to make a perfect cable and
to provide the exact results on the advance electronic
tests instrument.
- Conductivity tests.
- Insulation resistance.
- Velocity of propagation.
- Capacitance
- Corona Tests …etc.
| Radio
Frequency Coaxial Cables |
Item |
Conductor Size
mm |
Dia over Dielectric
(mm) |
O.D. (mm) |
Impedance (ohms) |
Attenuation
at 200 MHz (db/100 m) |
Max R.F. Operating
voltage (kv) |
Characteristic impedance
50-55 ohms |
RG-55B/U |
0.81 (S) |
2.95 |
5.2 |
53.5 |
20 |
1.9 rms |
RG-58 C/U |
19/0.18 (T) |
2.95 |
5.0 |
50 |
24 |
1.9 rms |
RG-58/U |
0.81 (P) |
2.95 |
5.0 |
53.5 |
23 |
1.9 rms |
RG-174/U |
7/0.16 (C) |
1.50 |
2.5 |
50 |
40 |
1.5 rms |
RG-212/U |
1.2(S) |
4.70 |
8.4 |
50 |
14 |
3.0 rms |
RG-213/U |
Similar to and substitutes
URM-67 and UR-67 |
. |
7/0.75 (S) |
7.25 |
10.8 |
50 |
11 |
5.0 rms |
RG-217/U |
2.7 (P) |
9.8 |
13.8 |
50 |
7 |
7.0 rms |
|
4.95 (P) |
17.3 |
22.1 |
50 |
4 |
11.0 rms |
|
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Characteristic Impedance 70-75 ohms |
RG-11 A/U |
7/0.41 (P) |
7.25 |
10.3 |
75 |
11 |
5.0 rms |
RG-216/U |
7/0.41 (T) |
7.25 |
10.8 |
75 |
15 |
5.0 rms |
RG-59/U |
0.63 (P) |
3.70 |
6.2 |
73 |
16 |
2.3 rms |
RG-59B/U |
0.58 (C) |
3.70 |
6.1 |
75 |
16 |
2.3 rms |
URM-202 |
7/0.25 (P) |
3.25 |
5.1 |
75 |
16 |
-do- |
URM-203 |
1.12 (P) |
5.10 |
7.3 |
75 |
11 |
Foam-PE dielectric |
URM-204 |
1.25 (P) |
5.60 |
7.8 |
75 |
10 |
-do- |
URM-206 |
1.4 (P) |
6.35 |
8.7 |
75 |
8 |
Foam-PE dielectric |
URM-210 |
7/0.19 (P) |
3.25 |
5.8 |
75 |
22 |
-do- |
URM-65 |
1.15(P) |
7.25 |
10.3 |
75 |
9 |
5.0 rms |
URM-70 |
7/0.19 (P) |
3.25 |
5.8 |
75 |
22 |
1.8 peak |
URM-77 |
2.65 (P) |
17.30 |
22.0 |
75 |
5 |
12.5 peak |
Similar to and substitutes RG-164/U |
|
|
|
|
Characteristic impedance 90-125 ohms |
RG-22/U |
2x7/0.38(P) |
7.25 |
10.3 |
95 |
20 |
1.00 rms |
RG-57A/u
Twin conductor |
2x7/0.12 |
12.0 |
15.9 |
95 |
12 |
3.0 rms |
RG-62A/u |
0.64 (C) |
3.7 |
6.1 |
93 |
12 |
0.75 rms |
RG-63 B/u |
0.64 (P) |
7.25 |
10.3 |
125 |
9 |
1.00 rms |
RG-71B/U |
0.64(P) |
3.7 |
6.4 |
93 |
12 |
0.75 rms |
UR-78 |
0.61 (P) |
7.25 |
10.3 |
100 |
11 |
3.7 rms |
|
