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Barrel connector12/29/2023 ![]() RF components such as bullets, barrels and connectorX-to-connectorY adapters (where X is one type and Y a different type) also result in some loss of signal. Variable 3) Loss from Adapters, External Components Generally, the less lossy a cable, the more expensive it is due to manufacturing and material complexities. Again, the particulars of your installation will determine what's tolerable loss. Depending on your application, that ~8.25 dB of loss could be the difference between an excellently-performing system and one that barely works, if at all. Remember, loss is specified in dB scale, which means every ~3 dB decrease is equivalent to a power drop of roughly one-half. For other cable types you can calculate your loss using this transmission line loss calculator site.So what the figures tell us is that instead of sending the antenna close to 1W (assuming a loss free cable), the original 1W of power has been reduced to only ~150 mW by the time it reaches the antenna. Referencing the table above means ~8.25 dB of power (.5 x 16.50) has been lost via the cable before the signal even gets radiated into the air by the connected antenna. To illustrate by way of example, assume you have an antenna cable which is 50' long. This is especially true in many supply chain and asset tracking applications where getting enough power to the tags proves challenging sometimes. To achieve the best performance in most cases, you'll want to ensure as much power leaving the reader actually gets to the antenna before being deliberately radiated. The following table is a useful general* guideline to show the relationship b/w cable type and the amount of loss you might expect to see. In runs of 8ft or less, it's common to use RG58 since the loss is tolerable and the cable is inexpensive compared to other types. RG58 is fairly lossy in runs of up to 100', whereas LMR400 is significantly less lossy, but higher cost. Cable composition can either magnify or minimize the amount of loss. The longer the signal must travel down a guided path, the more loss (also known as signal attenuation) occurs. Variable 1) Insertion Loss Inherent to Cable Type/LengthĪll wire conductors have some degree of signal loss. ![]() Those variables are: (1) tolerable insertion loss (or, the amount of signal that can be lost as it travels down the wire without adversely affecting system performance) from the length/type of cable, (2) cost and (3) any insertion loss arising from adapters or external switching equipment such as the Antenna Hub. ![]() This question is hard to answer uniformly as a couple of variables routinely impact the decision. A barrel refers to an adapter with two male ends, while a bullet refers to an adapter with two female ends.įinally, we often are asked what type of cable to use. ![]() To accomplish this you'll need either a bullet or a barrel. Sometimes you may need to interface two cables that have the same gender ends. These facts are important when choosing the antennas and cables in your system. In contrast, the Impinj Antenna Hub uses Normal Polarity SMA ports. Stated otherwise, RP solely means either add or subtract the center pin based on the opposite center pin state of Normal.Īs you probably already know, the Impinj Revolution R420 and R220 readers have RP-TNC connection types for the antenna ports. Specifying the RP version of a particular connection only refers to the center pin. The quick takeaway is this: gender is always dictated by whether there are outer threads (female) or inner threads (male). For clarification purposes a 'male center' has a pin whereas a 'female center' does not. Typically, RP variants of connectors look like their Normal Polarity counterparts, with the exception that the center pins change (if present in NP, then not present in RP, and vice versa) Here's a quick example of NP SMA Male and a RP SMA Female. In addition to the connectors listed in that linked document, you may find RP (or Reverse Polarity) versions of these types. At some point in your RF adventures, you'll likely come across every one of these connector types. Here we will list a small subset of those terms and describe what they mean. Moreover, we will discuss the different types of cable (for connecting the reader to an antenna) in the marketplace, along with their general characteristics, and how to choose the appropriate cable.įirst, if you need to know about the different types of connectors, please click here to view this very helpful picture catalog of common RF connectors used in UHF RFID. The RF discipline uses a number of terms that may be unfamiliar. If you are new to the radio frequency space, you may find the content of this document useful. RF Hardware 101 - Bullets, Barrels, Connectors, Cable Choices
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