Low loss RF coaxial cables – comparing your options
This blog article entry considers the merits of choosing which of various low loss RF coaxial cables to use for IoT, LTE or LORA wireless applications where an external antenna is used to connect to router, gateway or terminal.
In this article, we will consider cables such as RG174, RG58, RF195, RF240 and RF400 as possible coaxial cable choices for your installation.
The first point to consider is that running extension or jumper cables between the antenna and the radio (router, modem, terminal, gateway, wireless device – for the sake of this article we’ll simply use the term radio) is that the cable will always introduce loss into the system. Whether you use very low loss, high quality coaxial cable or very thin and “lossy” cable, attenuation will be introduced between antenna and radio. A key area to focus on is to minimise the loss introduced by the cable in order to maximise the performance of the antenna. On longer cable runs it is very important to use low loss RF coaxial cables otherwise attenuation is too great for a functional wireless deployment.
Looking at RG174, it is a thin coax typically with a PVC sheath and can be used often for lower frequencies up to a very maximum of 2-3 metres. Most often it is used for what we call “pigtail” or adapter cables which a short cables that typically connect a cable to radio often to convert from one connector to another or if a connector presenting to the radio is too small to be fitted to a very low loss coax. (RF400 cables are 10.2mm diameter and as such connectors like MMCX, QMA, MCX cannot be fitted to RF400).
RG58 is a stranded coaxial cable about 5mm in diameter. It can be used for longer runs than RG174, however we typically recommend customers switch to RF195 which is also 5mm in diameter, but due to its solid copper core and superior insulation is lower loss than RG58.
RF195 is typically used in cable runs for 4G and cellular applications up to maximum cable run of 10M. Any more than 10M then the attenuation introduced by the cable into the system starts to affect the overall performance. The advantages of RF195 is that it is cost-effective, flexible and has good RF properties making it ideal for 5M extension cable requirements.
For longer runs that RF195 offers or for lower loss performance over 5 to 10M, then RF240 low loss coaxial cables are an ideal selection. RF240 is very similar to LMR240. With an overall sheath diameter of 6.1mm, it can be offer in a PVC all-purpose sheath or a LSZH (Low Smoke Zero Halogen) CPR Class Eca compliant sheath. RF240 could be used up to about 15M cable runs for 4G and cellular applications and probably shorter runs if using it for WiFi. Once again, RF240 is cost-effective, but it is also flexible and robust making it ideal in installations where cable routing might be a little tricky.
For even longer cable runs, we have RF400 with PVC sheath for multi-purpose applications and RF400 LSZH Eca cable. These two cables are very low loss and we supply cables runs up to 50 or 60M depending on the frequency used in the installation. Both RF400 low loss RF coaxial cables are approx. 10mm in diameter, offering a little bit of flexibility, but most key is excellent RF properties meaning that you can minimise attenuation from the antenna to radio in your system.
EAD is a UK-based vendor of antenna solutions from 100 MHz to 6 GHz and also custom-assemblies low loss coaxial cables to customer specifications. For more information, please visit our product pages at www.customcoax.co.uk or contact us for specific requirements or questions you may have.
