About LMR 400 Coaxial cable
LMR-400 is a low-loss 50- ohm coaxial cable. It is designed to replace low-quality cables like RG-4. The term “ 400 “ is used to mention its diameter as LM$ 400 has a diameter between 0.405 to 10.29 mm.
The feature that distinguishes LMR 400 from other antenna cables is its “ low material loss and low signal loss as compared to other hard line and semi-rigid cables.
Uses:
LMR 400 Cable is commonly used to connect
- Antennas
- Receivers
- Meters
- Radio
- Transmitters
- Other applicable RF Sources
Step Wise Installation Guide for LMR 400 coaxial cable
Guide PDF
Step 1: Coax Stripping
Before removing the black jacket, trim your cable to the appropriate length and then around 0.54 inches. Cut the braid/foil back 0.23 inches from the freshly cut end after the jacket is stripped. Lastly, remove 0.12 inches of the dielectric from the fresh central conductor from one end down. The braid must be trimmed back more than the dielectric
to ensure that neither the braid nor the foil touches the centre conductor, use a dielectric.
might result in a short.
Must Note: avoid nicking the braid, dielectric, and centre conductor. If contact is to be crimped, centre conductor tinning is not required. If the centre conductor is stranded, tin it before using the soldering technique. Prior to tinning, the centre conductor must be securely twisted.
Method of installation
You have to select any of the following two methods of installation
- Crimp on Method
- Solder on method
1. Crimp-On Method
With the help of the 7505-HANDLE Ratcheting crimp handle and the 7505-DIE-400 with a hex of 0.128 and 0.10 placed as the centre pin. Starting at the pin crimp point, use the big hex value of 0.128. You might need to use the 0.10 hex to establish a secure connection, depending on the type of coax being utilised.
Please note that you do not need to crush the centre conductor or over crimp
2. Solder On Method
The solder hole must be facing upward. Directly beneath the solder hole, touch the central pin’s underside with the soldering iron. Through the solder hole on the centre pin, apply solder to the centre conductor. Allow the solder to melt from the metal’s heat so that it may flow into the middle pin. Only a small amount of solder is required to complete the connection once the solder has melted. Make sure the solder doesn’t collect over the solder hole. There shouldn’t be any impediments on the centre pin’s exterior that would prevent insertion. Avoid overheating the middle pin, which can cause the coax’s dielectric to bulge.
Step 2: Main Body Installation
The second step is the Main body installation. You have to put the cable assembly, which has the centre pin already attached, into the connector’s main body. The main body’s knurled section can be slid under the coax braid.
Proceed the process by pushing cable assembly into the main body till the time when the centre pin of the connector snaps into place in the dielectric of the connector
Over the braid and flush against the connector body, slid the ferrule (attached to the coax at the start of Step 2) into position. At the location illustrated in the image below (on the ferrule, but right up against the main body of the connection), crimp the ferrule using the 0.429 hex of the 7505-DIE-400 that has been put into the ratcheting crimp handle 7505-HANDLE.
Step 3: Final Testing
As a last check, you should always use an ohmmeter set to a low resistance scale to measure resistance from the centre pin to the body. After making sure the coaxial cable’s opposite end doesn’t have any braid-to-centre pin shorts, you have to encounter unending pushback (open).
Make one last check to ensure there is no extra solder by looking at the middle pin’s tip. This can make it more difficult to fit the PL-259 connection’s tip easily into the female (SO-239) connector. Even a small amount of extra solder is typically simple to remove. Smooth the soft solder by lightly scraping it with the edge of a knife. Your PL-259 installation is now complete, and the connector is ready for use!
Useful tips For coaxial cable Wiring
https://readytogocables.com/tips-for-coaxial-cable-wiring/
1. Select the appropriate Coaxial cable
It is important to use the appropriate coaxial cable for that specific application. The inappropriate cable will take more time, effort and money.
2. Launch the Coax
The cable will twist as it unravels if you lay a cable spool on its side and begin pulling on it; twisted cable kinks when you pull on it. It’s best to insert a conduit piece in the centre of the spool and support it on a ladder
3. Use stripping tool
Although you can use a utility knife for stripping coaxial cable bur it is hard. You should use stripping tool for fast striping ofcoaxial cable . It will save yourtime and give you perfect results.
4. Make Stable Connections
If your dieletricis is not pushed flush with the connector then you will never receive a good connection. If you find it hard then it means you have wrong connector for cable you are dealing with.
5. Keep Coax cable away from electric lines
If You keep coaxial cable too close to electric lines then it will interfere with the signals. You must keep coaxial cable atlet at a distance of 6 inches from electric lines
Final Note
LMR 40 is a type of coaxial cable switch designed to replace low-quality cables like RG-4. The feature that distinguishes LMR 400 from other antenna cables is its “ low material loss and low signal loss as compared to other hard line and semi-rigid cables. This coaxial cable is widely used to connect radio, receivers, antennas and other RF sources. The installation of coaxial cable is a bit technical and need a careful approach to doing it properly and safely. Using the tips makes this process much simpler and easier for beginners.
