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Types of RF connectors. RF connectors for antennas and cables Frequency analysis of UHF connector

15.08.2023

RF Connectors for Coaxial Cable are of utmost importance in the construction of antenna-feeder paths and coaxial communication lines. The quality of manufacturing of these small and, at first glance, insignificant parts largely determines the stability and durability of the radio system. Even a small mistake in the production or sealing of a connector on a cable can cause a lot of trouble, which is worth just replacing the connector on a fifty-meter antenna mast in severe frosts!

When selecting an RF connector, adapter, or lightning arrestor for an antenna First of all, you should start from the reliability of the manufacturer and supplier, since it is problematic to visually determine the quality and compliance of the characteristics. Nevertheless, quality is very important, cheap Chinese RF connectors cause difficulties in soldering and installation, and also cause severe signal attenuation in the connections, not to mention the fact that such fakes can simply rust or rot when used outdoors.

To choose the right RF connector, you should take into account the cable used, the power of the radio signal in the line and the maximum frequencies. The choice here is very diverse; below we provide a list of the most popular types of RF connectors, as well.

    Main types of RF connectors (connectors):
  • BNC - bayonet connector. Rotating connection using a latch, which is important when using frequencies, for example, connecting an antenna to a radio station. Maximum frequency 4 GHz.
  • TNC is a threaded analogue of a BNC connector; it has good contact even in conditions of constant vibration. Maximum frequency 11 GHz.
  • N is perhaps the most common RF connector in the world of professional radio communications, because... meets all requirements for radio signal propagation in coaxial lines. Available for cables with a diameter of up to 11 mm, Maximum frequency 18 GHz.
  • SMA - a miniature RF connector has found wide use among manufacturers of wearable radio stations. Almost all antennas for walkie-talkies use this type of connector. Maximum frequency 18 GHz.
  • 7/16 - professional RF connector for basic equipment and antenna-feeder paths of fixed communication stations (alternative name L29). Marking: 7 mm – diameter of the central core, 16 mm – internal diameter of the shielding braid. The threaded connection is designed for operation in humid and difficult climatic conditions. Maximum frequency 18 GHz.

All RF connectors are divided into two groups: plug (male, plug, male, plug) and socket (female, socket, jack, female), as well as connectors are divided according to design - straight, angular, for mounting in a hole or on a panel and according to the method of sealing on cable - for soldering, screw-on, crimp and clamp.

MAIN TYPES OF RF CONNECTORS AND THEIR OPERATING FREQUENCIES

The plate is from the Internet, and in some places it is correct. My comments are below.
connector work strip connector work strip
BNC 0-4 GHz N 0-11 GHz
F 0-2 GHz TNC 0-11 GHz
FME 0-2 GHz mini-UHF 0-1 GHz
SMA 0-12 GHz UHF 0-300 MHz
SMB 0-4 GHz

The incompetence of the unknown compiler of this table is manifested in a lack of understanding of the material that he is trying to systematize. See for yourself:

1. BNC and TNC connectors are the same connector, the only difference is in the fixing nut, which does not affect the electrical parameters and can (and does!) even be made of plastic.

2. SMA and SMB connectors - the same.

3. connector F - only “male” has satisfactory parameters in the specified range. Most F(f) - begin to spoil the matching already at 600 MHz. N.B. There is F(f) of a special “pouring” (blue dielectric), they correspond to the table.

4. Most UHF connectors imported to Russia from China are of low quality and work well up to 60 MHz. Small dances with a tambourine allow them to be used up to 150 MHz. Pay attention to the UHF socket located on the transceiver or SWR meter; these connectors are frequency-compensated and their characteristic impedance is reduced to 50 Ohms.

For supporters of the UHF connector - an abbreviated translation of comparative testing of UHF and N connectors.

Chris Arthur Jr. /VK3JEG - http://www.qsl.net/vk3jeg/pl259tst.html :) pls do not kick me when you see a mistake.

Frequency analysis of UHF connector.

A closer look at the connector with non-standardized impedance - PL-259 and SO-239.

Introduction. The UHF connector came into its own in the early 1930s, when VHF/UHF technology was relatively new. The ancestors of the UHF connector were in many cases experimental radio amateurs, most of them with an engineering or technical education, who began experimenting and working with the VHF band around 1926.

A little later, research also began in FM radio and TV, which eventually gave this connector the name UHF.

At that time, mathematical models of the field and EMF were sufficiently defined by J. Maxwell and his followers. Nevertheless, there were problems of a physical nature - instruments and applied science did not develop so quickly. The results of this period of development of radio and telecommunications were often obtained through experimental trial and error methods, using instruments that are now considered crude.

Target . Show problems associated with RF connectors with non-standardized impedance.

(translating slowly.....)

Of particular interest is the now inappropriately named UHF type connector, known more commonly as the PL-259 (Male) and SO-239 (Female). The results gained here are primarily aimed at supplying fellow radio amateurs with information that is not readily available. Characterization will take place at frequencies around 146 MHz and the at UHF frequency of 438 MHz, where in actual fact this type of connector is not recommended for use.

Manufactures of UHF plugs and receptors all state that this type connector are of non-constant impedance and are suitable for use up to 200 or 300 MHz, depending on production quality. They also state that the UHF connector can be used up to 500 MHz with a cautionary note of reduced performance. A range of manufacturers specifications for the UHF type connector are included in appendix A. Connecters and adapters used in this test are also included. Note: appendix A is not included in html version.

Method How do we evaluate the characteristics of a connector? Well, to start with we would need to measure the impedance. Having established this we could then find the insertion and return losses. How do we measure these parameters? The most widely used instrument and preferred tool for RF engineers is the Network Analyzer. In this case I employed the use of the Royal Melbourne Institute of Technology"s Wiltron model 360B Vector Network Analyzer. This is a device that measures the magnitude and phase characteristics of RF networks, amplifiers, attenuators and antennas operating from 10 MHz to 40 GHz It compares the incident signal that leaves the analyzer with either the signal that is transmitted through a test device or the signal that is reflected from its input.

Procedure For this test I decided to simulate the amount of transitions that would be encountered in a transceiver to feedline, feedline to antenna situation, with the exception of the actual feedline. Further to this I will make a comparison with the N type constant impedance connectors using the same approach.

I used presicion 50 Ohm Test lines, 500mm in length, being terminated with APC-7"s at both ends, so APC-7"s to Male N types were added to each. The Network Analyzer is calibrated with the 50 Ohm test lines and adapters installed on each port using the supplied standards in the form of a 50 Ohm Cal Kit. A OPEN, SHORT and TERMINATION. Great care must be exercised with all cal kit components as they are quite expensive (around $1000AU ea).

UHF type adapters used in comparison

2 x Female N to PL-259 Adapters (simulating line connectors, PL-259"s)

1 x Female UHF Barrel Connector (simulating radio and Ant, SO-239"s)

2 x Female to Male N Adapters (simulating the line connectors,N Males)

1 x Female to Female N Adapter (radio and antenna connections,N FM"s)

Results Two of the N to PL-259"s were mated with a UHF (SO-239) barrel connector, this configuration then becomes the DUT for the UHF series of tests. A direct comparison is then made with an equivalent combination of N type adapters from 50 to 500 MHz, thus the results are presented as such. It should also be pointed out that all figures stated are as displayed at the time of testing, for the sake of simplicity we will ignore system errors and associated calculations.

The first comparison is that of Reverse Reflection Impedance, this is known as a S22 Parameter. In short the closer this figure is to one on the real axis of a Smith Chart, the better the match is to 50 Ohms. Results shown on the 1st Smith Chart verify that the UHF connector is as the manufacturer"s say, a non-constant impedance connector. At 146.3 MHz the Reverse Reflection Impedance of the combination is about 38 Ohms (ignoring the complex) at 432 MHz, the figure is almost 30 Ohms. Turning to Smith Chart 2 shows almost a perfect transition through the N type combination to 50 Ohms, right up to 500 MHz.

The next comparison was that of Forward Reflection or Return Loss known as a S11 Parameter. Return Loss is a measure of the dissimilarity between two impedance"s. The Amplitude of the reflected wave to the amplitude of the incident wave, expressed as a ratio, normally in decibels and is measured at the junction of the transmission line and a terminating impedance .In an ideal model there would be no measurable return loss because the load would receive and absorb all of the transmitted power but in the real world this is not the case as no system is perfect. A very good transmission system would have a return loss of around -30 to -20dB at microwave frequencies. A return loss figure of -20 to -10dB is what may loosely be termed as the norm for a reasonable transmission system working at VHF to Microwave frequencies. Good connectors exhibit return losses on the order of -40 to -30 dB and as we can see on the PL-259 & UHF Barrel data, it"s not quite within this range. Being at -15 dB for 146.3 MHz and a rather poor figure of around -8 dB at 432 MHz. On the next plot, we can see that the N type combination was fairly flat from 50 to 500 MHz, giving a much better result with return loss figures in the order of -35 to -30 dB across the same frequency range.

The final sets of comparison data is probably the most interesting to the VHF/UHF amateur being Forward Transmission or Insertion Loss known as S21 Parameter. This parameter is by name self explanatory and the comparison plots and data are presented on the last 2 sweep data plots. The Insertion Loss that we can see associated with UHF connector data is of course due to the non- constant Impedance transition. We can also see that this becomes more of a problem as frequency increases toward 500 MHz on the sweep data. At 144.5 MHz and 146.3 MHz the Insertion Loss runs around 0.2 dB, increasing to around 1 dB at 432 MHz. In comparison the Insertion loss for the N-type combination was very low, in fact almost immeasurable.

Conclusion Before wrapping things up I must admit that the UHF type barrel connector employed here was of fairly poor quality, as one would find in most hobby type outlets. I suspect that it contributed significantly to the poor results gained but we should also keep in mind that good quality connectors of the UHF type are not easily found. In real world terms the 0.2 dB Insertion loss at 144 MHz would be a transmission loss of more than 1 Watt from a 25 Watt input at 144 MHz. The real bad news is at 432 MHz where we see a loss in the order of 1.0 dB, this equates to a transmission loss of around 6 Watts with 25 Watts input. This phenomenon is of course due to the Impedance "bump", the power is not actually lost but reflected in the transmission lines.

Most of use have used a VSWR meter, a useful device for looking at reflected waves, a lot of these units also give a relative power reading. Perhaps at some time or another you may have noticed some particularly strange indications while using your meter at VHF/UHF frequencies. The problem with this type of instrument is that it is both frequency and impedance sensitive. We can normally recalibrate for the frequency of operation but impedance is fixed at 50 Ohms, therefore any mismatches on the line both before or after the meter will cause error in the indicated parameters. As we can see from our test results of the UHF type connector the Impedance is non-constant and at VHF and UHF frequencies offers a varying mismatch to 50 Ohms. This in turn will cause error in both VSWR and Power readings particularly at UHF frequencies. A more detailed description of interpreting Antenna and line measurements directed particularly at the Amateur was written by R Bertrand VK2DQ in the mid 1980"s, it can be found in the Amateur Radio Action, Antenna Book 3.

I would like to finish with these few points. The first being that the so named UHF connector from the past is not really suitable for use above 300 MHz at all. Perhaps the exception to this would be when a cheap and rugged system is required where loss and good signal to noise ratio is of little concern. Unfortunately it appears that both Amateur and CB Radio UHF type equipment fall into this category as many manufactures still supply SO-239 UHF receptors as standard equipment. The second point is that from our results we can see that utilization of the UHF connector at 146 MHz for FM type transceivers is not such a problem. A cheap rugged connector is probably an advantage as many FM units are used for mobile applications. However, for 144 MHz SSB type work where low loss and good signal to noise ratio is very desirable, again I would not recommend the use of UHF type connectors. The UHF connector still has a place in many applications where a robust economical RF connector is required but for serious applications its use should be limited to below 100 Mhz. As we have shown the N type is far superior in performance, it should also be noted the BNC type connector is similar in performance to that of the N type but has the disadvantage of being less rugged. In the end, one should always check with the manufactures specifications.

BNC connector was developed in the late 1940s. BNC stands for Bayonet-Neill-Concelman. The bayonet defines the connection mechanism, while Neil and Conselman are the inventors of the connector (N-type bayonet). BNC connectors (connectors) are used in many applications (networking, instrumentation, computers and peripheral equipment). BNC series RF connectors are used with cables with a diameter of up to 7mm. Losses in these connectors do not exceed 0.3 dB. These connectors are connected using a bayonet lock and are designed for networks with a resistance of 50 Ohm up to 4GHz, 75 Ohm up to 1 GHz. Plugs, sockets, terminators, protective caps, and adapters are produced. Solderless - fastening the central core with a screw.

F connectors designed for television equipment. The cheapest RF connectors available today use the central core of the cable directly for connection. Operates up to frequencies of 1200MHz, with cables up to 7mm in diameter. Plugs, sockets, and adapters are produced.

N connectors developed by P. Neil from Bell Labs and are the first connectors to most fully meet the requirements of the microwave range. N series connectors designed for 50 ohms can be used in a fairly large selection of resistances. They are suitable for 75 ohm resistance, although they are not interchangeable with 50 ohm standard models. Typically available with 50 ohm impedance and operating up to 11GHz. Some versions may have a cutoff frequency of up to 18GHz.

The scope of application of N connectors is local networks, measuring equipment, radio broadcasting, satellite and military communications equipment. Plugs, sockets, terminators and protective caps, adapters are produced.

TNC connectors are a variant of BNC connectors with unifying characteristics. Cable configurations and installation procedures are very similar to the BNC series. Plugs, sockets, terminators and protective caps, adapters are manufactured.

UHF connectors were invented in 1930. Clark Quackenbush (Amphenol Company) for the broadcast industry. The UHF plug is usually called PL-259 according to the military listing. UHF connectors have a screw connection and are characterized by variable impedance. In this regard, their use is limited to frequencies up to 300MHz. These connectors are classified as inexpensive and are used mainly for low-frequency (LF) communication equipment. They operate stably up to 300-400MHz with minor losses. UHF connectors - popular and economical - are used when impedance matching is not required. The M and UHF series are similar in structure and efficiency, but are not interchangeable without an adapter due to different screws at the connection point. Manufactured for cables with diameters from 5 to 18 mm. They make plugs, sockets, adapters.

Mini UHF Compact and lightweight connectors designed specifically for applications requiring miniaturization. They are characterized by impedance variability and operate satisfactorily at frequencies up to 2 GHz and voltages up to 335 V, but have a power transmission limitation of up to 100 W. Available for coaxial cables with a diameter of up to 6.25 mm. They have high reliability. They make plugs, sockets, and adapters.

RCA connectors a standard widely used in audio and video technology. The name RCA comes from the Radio Corporation of America, which introduced this type of connector in the early 1940s for connecting phonographs to amplifiers. In Russian, this type of RF connector is often called “tulip” or “bells”.

SMA connector(sub miniature type A) - developed in 1960. Originally for 0.141" semi-rigid cable (RG-402). The connectors are designed for 50 ohm impedance, some precision versions can operate up to 26.5 GHz. The maximum operating frequency for cable connectors is determined by the cable type. SMAs have a wide range of applications, where the key parameters are overall dimensions and cutoff frequency. They are used in many microwave devices (coaxial-waveguide and microstrip junctions, amplifiers, attenuators, filters, mixers, master oscillators and switches). The connectors are made of stainless steel and have increased reliability and mechanical strength. Meets specification: MIL-C-39012. Frequency range - from 0 to 12 GHz. They make plugs, sockets, and adapters.

FME connectors are used to connect terminal devices (mobile communication systems, radio extenders, cellular terminals, etc.) with mobile antennas and are adapted to UHF, Mini UHF, TNC, BNC and N interfaces. The design of the rotating nipple allows it to rotate on 360° with subsequent fixation of the connection with a union nut, which provides flexibility when connecting mobile communication equipment. FME connectors are rated at 50 ohms impedance and are designed to operate at frequencies up to and including 2 GHz. There are modifications for coaxial cables RG-58/U, RG-59/U, RG-174/U.

SMB connectors(subminiature connector, type B) are miniature connectors designed to operate at frequencies up to 4GHz. The small size and connections make SMB an ideal connector. They are used in telecommunications, testing equipment and tools, satellite communications, and navigation devices. Available in 50-ohm and 75-ohm impedances, they can operate over a wide frequency band up to 4 GHz. Typical uses of SMB include board-to-board and interconnect connections for RF and digital signal transmission, telecommunications and test equipment, and high-precision electronic instruments. They produce plugs, sockets, adapters both for crimping and for attaching to a cable using soldering.

MCX connectors microminiature connectors introduced in the 1980s and meeting the requirements of the European standard CECC 22220. Have the same center pin and insulator dimensions as SMB connectors, but the outer diameter of the socket is 0.14 inches, which is 30% smaller than connectors SMB series. This feature provides designers with the opportunity to use them where space and weight savings are particularly important. The snap mechanism allows for quick connection/disconnection. The MCX is available in 50 and 75 ohm impedances and is capable of low reflection operation at frequencies up to 6 GHz and 1.5 GHz, respectively.

MMCX connectors(smaller version of MCX) - also called C2.5 or MicroMate™. This is a line of one of the smallest RF connectors developed by Amphenol in the 1990s. and is a series of micro-miniature connectors with a snap-in mechanism that allows 360° rotation, providing flexibility for use with printed circuit boards. MMCX connectors meet the requirements of the European specification CECC22000. This family of devices is a 50 ohm impedance interconnect system with low reflectance broadband capabilities up to 6 GHz for high quality signal transmission. Connectors of different types are produced: cable, for surface mounting and end (comb) for printed circuit mounting.

For high-quality operation of a cellular signal amplifier, receiving and distributing antennas, and routers, a good cable assembly is simply necessary. And one of the most important links here are the RF connectors. How to choose the right coaxial connectors, how does one type differ from another? All this will be discussed below.

This is what we call a bayonet connector. It was created back in the first half of the 20th century and is one of the founders of RF connectors and is widely used to this day. The main feature is the connection due to the original clamp with a latch. This simplifies operation with frequent disconnection and connection and guarantees reliable contact (signal loss - no more than 0.3 dB). The maximum cable diameter along the sheath is 7 mm. For networks with a characteristic impedance of 50 Ohms, a frequency of no more than 4 GHz is permissible.

The threaded BNC variant, developed in the late 1950s, is capable of operating at frequencies up to 11 GHz. Also among the positive differences of the format is better contact, especially in conditions of high vibrations. Cable diameter – 3-10 mm.

Another widespread type. The part that fixes the cable with a diameter of 5-8 mm is made in the form of a nut that is screwed onto the screen (outer conductor). In this case, the role of the plug is played by the bare central core, which narrows the range of feeders used (there must be a monolithic core resistant to corrosion and wear). Most often used in television networks at frequencies up to 2 GHz. The main advantages: simplicity and price.

A smaller analogue of the F-standard. It was developed for connecting portable equipment and has found wide application in cellular communications. The diameter of the cable along the sheath should be from 3 to 5 mm. Operates in the frequency spectrum up to 2 GHz. FME is often used with RG-58 cable.

One of the most popular connectors, since its characteristics most fully meet the requirements for microwave signal transmission. There are various subtypes depending on the installation (crimp, solder, clamp). The N-connector can operate effectively at frequencies up to 18 GHz. Suitable for cable diameters from 3 to 10 mm.

Subminiature connector A, characterized by small dimensions (cable diameter - 3-5 mm) and a high operating frequency level - 18 GHz. Initially designed for a characteristic impedance of 50 Ohms. Stainless steel construction includes a durable metal plug and threaded mounting (hex nut).

The abbreviation stands for “reverse-polarity Sub-Miniature version A”. Suitable for use with RG-58 coaxial cable. The small-sized reversible connector (reverse polarity SMA) is widely used to connect WiFi equipment. As a rule, the feeder is fixed using crimping.

Modern, large socket. The marking numbers indicate the following: 7 mm – outer diameter of the central core, 16 mm – inner diameter of the braid (outer conductor). The connectors are used for powerful equipment (mainly used at cellular base stations) and have a reliable threaded connection with a high degree of moisture and dust protection. Operating frequency – up to 7.5 GHz (flexible cable) or 18 GHz (semi-rigid cable). An alternative designation for the series is L29.

In addition to division into series, there are other factors that determine the appropriateness of the choice.

Type:

  • plug (plug, male, plug, male);
  • socket (socket, “mother”, jack, female).

By polarity:

  • standard (straight) polarity: “male” comes with a pin, “mother” comes with a socket;
  • reverse polarity (RP marking): “male” – socket, “female” – pin.

By design:

  • straight;
  • corner.

According to the type of fastening of the central contact:

  • for soldering (the contact is soldered with tin to the central core of the cable);
  • crimp (the contact is put on the central conductor and crimped).

According to the type of housing fastening (metal braid of the cable to the housing):

  • Clamping. The cable contact area is equipped with a threaded metal bushing. It is screwed into the body, exerting pressure on the pressure sleeve. The advantage of such a connector is the relative ease of installation, no need for special tools (only a wrench, a utility knife and scissors). The disadvantage of this choice is the average connection reliability.
  • Crimping. Unlike the previous type, the part of the connector responsible for fixing the braid does not have a thread. The feeder is secured using a crimp sleeve(s). Crimping is done using a special tool - a crimper. Crimp connectors have good mechanical strength and good electrical contact.

By type of connected cable:

  • F – for RG-58 or other cable with a diameter of 3 mm;
  • /5D – for cable 5D-FB/CNT-300/LMR-300 or other with a diameter of 6.5-7 mm;
  • X – for RG-213 cable with a diameter of 10 mm;
  • /8D – for cable 8D-FB/CNT-400/LMR-400 or other with a diameter of 10-11 mm;
  • /10D – for cable 10D-FB/CNT-500/LMR-500 or other with a diameter of 13 mm.

Result:
If you need a cable for video surveillance, satellite or terrestrial TV, then an inexpensive 75 Ohm cable is suitable. Brands, RG-6, RG-59.
If you need a cable for a local Ethernet computer network or for wired telephony, then use a twisted pair cable

N-Type- connector developed in 1940 at Bell Labs by Paul Neil ( Paul Neill), "N" appeared in the name of the connector thanks to the first letter of his last name. Initially, the connector was developed for frequencies up to 1 Gigahertz, but later its potential for use at orders of magnitude higher frequencies reaching 11 GHz was revealed, and thanks to subsequent refinement by Julius Bokta ( Julius Botka) from Hewlett-Packard, the connector began to be used in systems operating at frequencies up to 18 GHz and today can rightfully share the glory of one of the most common high-frequency connectors with its predecessor - UHF.

The connector has not found much recognition among radio amateurs and civilian users, but has gained continued popularity among professionals and is used in mobile communications infrastructure, wireless data transmission (WiFi), paging and cellular communication systems, as well as in cable television networks, standardized according to MIL protocols -C-39012.

The N connector is physically larger than BNC or UHF connectors, and is therefore better suited for large diameter, low loss cables.

Technical characteristics of N-Type connectors

The threaded connection of the connectors helps to obtain high quality signal transmission. Properly tightened threads protect against vibration losses and virtually eliminate physical breakage of the connection. N-type connectors use air as insulation between the contacts.

The threads on the connector are tightened by hand. The tightening force is 1.7 N*m. In the usual kgf (kilogram in the Earth's gravitational field) it will be about 170 grams with a lever of 1 meter. It turns out that in order to tighten the thread on an N type connector with a radius of 8 mm, you need to apply a force of 21 kilograms (kgf). This is not much for human hands, and practice shows that simply tightening the connector by hand is sufficient for a high-quality mechanical connection.

The stainless steel connector allows threads to be tightened approximately 1.5 times tighter. The numbers above are for a brass body.

Cable type: coaxial
Characteristic impedance Ω: 50 Ohm
Mounting: 5/8-24 UNEF thread
Operating frequency: 0.001-11 GHz (up to 18)
Diameter - male connector: 21 mm (21-23.6)
Diameter - female connector: 19.1 mm (16-22)

Features of N-Type connectors

N-type connectors are popular when you need to transfer a significant amount of power. The actual power transmitted varies greatly depending on the connector manufacturer. What materials are used, what kind of coating, how well the contacts are connected.

The maximum power that an N-type connector can transmit is determined by the voltage drop across the pin. At the same time, the average power is determined by the heating level due to the resistance of the pin at the connection points. Due to the skin effect, it is frequency dependent. The new connector, with an ideal SWR, can withstand 5 kW at 10 MHz, and at 2 GHz already 0.5 kW of power.

N-type connector materials

The housing of N-type connectors is made of evaporated brass, as well as passivated stainless steel. Mother contacts are either baked beryllium copper or phosphor bronze, or coated with gold, silver, copper alloys and passivation.

Mother contacts: beryllium copper, phosphor bronze
-male contacts: phosphor bronze, brass
O-ring: Silicone, GR 50-60
Body: brass, stainless steel
Dielectric: PTFE fluorocarbon

Coating - male contact: silver, gold
Coating - mother of contact: nickel, gold, silver, copper alloys, passivation

N-Type connector
50 and 75 Ohm

In addition to the 50-Ohm N-type connector, there is also a 75-Ohm version. The 50 Ohm connector has a larger pin to reduce resistance at the center pin. Otherwise, they are not significantly different and therefore they can be physically connected. If you make an effort and drive such a pin into the socket of a 75-Ohm connector, this can cause irreparable damage to the female connector. But if the manufacturer has provided enough elasticity to the connector socket, then it will still be functional.

History of N-Type connectors

The development of the N-type connector began out of a need for an efficient constant impedance RF connector. At first, N-type was intended to operate at frequencies up to 1 GHz. Since then, the connector has found use in many applications that require high transmission line efficiency, the ability to transmit high powers and larger coaxial cable diameters.