Types of RF connectors. Boundary frequencies for RF connectors RF connector

N-Type- The connector was designed in 1940 in Bell Labs Paul Neil ( Paul Neill), "N " The title of the connector appeared thanks to the first letter of his last name. Initially, the connector was developed for frequencies of up to 1 gigahertz, but later it was revealed by its use potential and an order of high frequencies reaching 11 GHz, and thanks to the subsequent revision by the Julius with a bed ( Julius Botka.) From Hewlett-Packard, the connector began to be used in systems operating at the frequencies up to 18 GHz and rightfully can divide the fame of one of the most common high-frequency connectors with its predecessor - UHF.

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

N connector is physically larger than BNC or UHF connectors, and therefore it is better suited for large diameter cables and small losses.

Specifications N-Type connectors

The threaded connection of the connector helps to obtain high quality signal transmission. How the tightened thread should protect against losses during shaking and practically eliminates the physical tip of the connection. In the n-type connectors, air serves as insulation between the contacts.

The thread on the connector is delayed manually. The tightening force is 1.7 n * m. In the usual kgf (kilogram in the gravity field) it will be about 170 grams with a lever 1 meter. It turns out to tighten the thread on the n type connector of an 8 mm with a radius of 21 killograms (kgf). This is a bit for human hands, and practice shows that simply tighten the connector with the hands is enough for a high-quality mechanical connection.

Stainless steel connector allows you to delay the thread about 1.5 times stronger. The numbers are higher - for the brass case.

Cable type: coaxial
Wave resistance Ω: 50 ohm
Fastening: Thread 5 / 8-24 UNEF
Frequency of work: 0.001-11 GHz (up to 18)
Diameter -pad connector: 21 mm (21-23.6)
Diameter - Mama Connector: 19.1 mm (16-22)

Features N-Type connectors

Type N connectors are popular when you need to convey a significant amount of power. The actual value of the transmitted power strongly depends on the manufacturer of the connector. What materials use, what a coating, how well the contact is connected.

The limit power that the N-Type can transfer the connector is determined by the voltage drop on the pin. At the same time, the average power is determined by the level of heating due to the impedance of the pin at the points of the connection. Due to the surface effect, it depends on the frequency. The new connector at the perfect KSW can withstand 5 kW per 10 MHz, and 2 GHz is already 0.5 kW of power.

N-Type Materials connectors

The N-Type housing of the connectors is made of brass with spraying, as well as passivated stainless steel. Mom-contacts are either from burned beryllium copper or phosphoric bronze, or with a spraying of gold, silver, copper and passivation alloys.

Mom Contacts: Beryllivaya Copper, Phosphoric Bronze
Pap Contacts: Phosphoric Bronze, Brass
Sealing ring: Silicone, GR 50-60
Case: Brass, Stainless Steel
Dielectric: Ptfe Fluorocarbon

Contact cover: silver, gold
Contact Coating: Nickel, Gold, Silver, Copper Alloys, Passivation

N-Type connector
50 and 75 ohms

In addition to the 50-ohm N-Type connector, there is another 75-ohm version. The 50-ohm connector has a larger pin to reduce resistance on central contact. Otherwise, they do not differ significantly and therefore they can be physically connected. If you make an effort and drive such a pin into the 75-OMO connector socket, then this may apply a connection to the connector, irreparable damage. But if the manufacturer laid enough elasticity of the connector socket, then it will still be operational.

History of N-Type connectors

The development of the N-type connector began as needed in an effective radio frequency connector with constant resistance. First, N-TYPE was used to work at frequencies to 1 GHz. From this point on, the connector has found applied in many applications where the high efficiency of the transmitting line is required, the ability to transmit high power and larger diameter coaxial cable.

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

So call the bayonet connector. It was created in the first half of the 20th century and belongs to the number of RF connector generators, is widely used to this day. The main feature is a connection due to the original retainer with the latch. This simplifies operation when you are frequently connected and guarantees reliable contact (signal loss - no more than 0.3 dB). The maximum cable diameter for the shell is 7 mm. For networks with a wave resistance of 50 Ω, the frequency is not more than 4 GHz.

The BNC threaded version, developed in the late 1950s, is able to work at a frequency of up to 11 GHz. Also among the positive differences in the format are the best contact, especially in the conditions of large vibrations. Cable diameter - 3-10 mm.

Another widespread type. A portion fixing the cable with a diameter of 5-8 mm is made in the form of a nut, which is screwed to the screen (external conductor). At the same time, the role of the plug is performing the bare central lived, which narrows the circle of the feeders used (there must be a resistant to corrosion, the monolithic lend to the wear). Most often used in television networks at a frequency of up to 2 GHz. The main "pros": simplicity and price.

Reduced analog F-standard. It was designed to connect portable techniques, was widely used in cellular communication. The cable diameter of the shell must be from 3 to 5 mm. Works in the frequency spectrum to 2 GHz. FME is often used with RG-58 cable.

One of the most popular connectors, as in its characteristics to the most fully meets the requirements for the transmission of the microwave signal. There are various subspecies depending on the installation (crimp, under the soldering, presser). The n-connector can effectively work at frequencies up to 18 GHz. Suitable cable with a diameter of 3 to 10 mm.

Subminiature connector A, characterized by small dimensions (cable diameter - 3-5 mm) and high operating frequency bar - 18 GHz. It is originally designed for the wave resistance of 50 ohms. Stainless steel design includes a durable metal plug and a threaded mount (hex nut).

Abbreviation is decrypted as "Reverse-Polarity Sub-miniature Version A". Suitable for working with coaxial cable RG-58. A small-sized reverse connector (Reverse Polarity SMA) is widely used to connect WiFi equipment. As a rule, the fixation of the feeder is performed using crimping.

Modern large connector. Marking figures indicate the following: 7 mm - the outer diameter of the central vein, 16 mm - the inner diameter of the braid (external conductor). Connectors are used for powerful equipment (mainly used at base stations of cellular communication), have a reliable threaded connection with a high degree of moisture and dustproof. Operating frequency - up to 7.5 GHz (flexible cable) or 18 GHz (semi-rigid cable). Alternative designation of the series - L29.

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

Type:

• plug (plug, "dad", plug, male);
• nest (socket, "Mom", Jack, Female).

By polarity:

• standard (straight) polarity: "Dad" goes with a pin, "Mom" - the nest;
• reversible polarity (RP marking): "Dad" - nest, "Mom" - pin.

By constructive:

• straight;
• corner.

By type of fixing center contact:

• under the soldering (contact is soldered by tin to the central cable dwelling);
• crimp (contact is put on the central conductor and crimped).

By the type of casing mounting (cable metal braid to the case):

• Clamping. The contact area with the cable is equipped with a metal sleeve with a thread. It is screwed into the housing, putting pressure on the pressure sleeve. The advantage of such a connector is the relative ease of installation, no need for special tools (only wrench, stationery knife and scissors). The disadvantage of this choice is the average reliability of the compound.
• Crimp. In contrast to the previous species, part of the connector that is responsible for fixing the braid does not have a thread. The fifth of the feeder is ensured by crimping bushings (sleeves). The crimp is made using special tool - a crimper. Crimp connectors are characterized by good mechanical strength and good electrical contact.

By type of connected cable:

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

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

RF connectors for coaxial cable These are essential when building antenna feeder paths and coaxial communication lines. The quality of the manufacture of these small and, at first glance, insignificant details, largely determines the stability and durability of the radio system. Even a small error in the production or sealing of the connector on the cable can deliver a lot of trouble, which is worth only the replacement of the connector for fifty meter antenna mast into severe frosts!

When choosing a HF connector, antenna adapter or a slope First of all, it is worth repelled from the reliability of the manufacturer and the supplier, as we visually determine the quality and conformity of the characteristics is problematic. Nevertheless, the quality is very important, cheap Chinese RF connectors cause difficulties when solding and mounting, as well as cause strong attenuation of the signal in the connections, not to mention the fact that such fakes can be simply rushing or digging with outdoor use.

To properly select the RF connector, it is necessary to repel from the cable used, the power of the radio signal in the line and maximum frequencies. Here the choice is very diverse, below we give a list of the most sought-after types of HF connector, but.

The main types of RF connectors (connectors):
• BNC - Bayonet connector. Swivel with a retainer with a latch, which is relevant with the frequency of use, for example, an antenna connection to a radio station. Maximum frequency of 4 GHz.
• TNC - the threaded analog of the BNC connector, has a good contact even in conditions of constant vibrations. Maximum frequency of 11 GHz.
• N - perhaps the most common RF connector in the world of professional radio communications, because meets all the requirement to spread the radio signal in coaxial lines. Produced for cables with a diameter of up to 11 mm, the maximum frequency is 18 GHz.
• SMA - Miniature RF connector has been widely used in manufacturers of wearable radio stations. Almost all the antennas for portable racies use a connector of this type. The maximum frequency is 18 GHz.
• 7/16 - Professional RF connector for basic equipment and the antenna feeder paths of inpatient communication stations (alternative name L29). Marking: 7 mm - the diameter of the central vein, 16 mm - the inner diameter of the shielding braid. The threaded compound is designed for operation in wet and complex climatic conditions. The maximum frequency is 18 GHz.

All HF connector are divided Two groups: plug (dad, plug, male, plug) and a socket (mother, socket, jack, female), as well as connectors are divided into design - straight, angular, for mounting into the hole or on the panel and by the method of sealing The cable is under the solder winding, crimp and presser.

BNC connector was developed in the late 1940s. BNC is decrypted as Bayonet-Neill-Concelman. Bayonet determines the communication mechanism, while Nale and Concellman are inventors of connectors (bayonet N-type). BNC. connectors (connectors) Used in many applications (networks, measuring equipment, computers and peripheral equipment). The BNC series connectors are used with cables with a diameter to 7mm. Losses in these connectors do not exceed 0.3 dB. These connectors are joined using a bayonet lock and are designed for 50 Ohm resistance networks to 4GHz, 75 ohms to 1 GHz. Plugs, sockets, terminators, protective caps, adapters are produced. SOLDERLESS - fastening of central veins with screw.

F connectors Designed for television equipment. The cheapest at the very RF connectors using the central core core directly for the compound. Work to 1200MHz frequencies, with cables with a diameter up to 7mm. Plugs, nests, adapters are produced.

N connectors Developed by P.Nale from Bell Labs and is the first connectors most fully meet the requirements of the microwave range. N series connectors for resistance of 50 ohms can be used in a rather large selection of resistance. They are suitable for resistance of 75 ohms, although not interchangeable with the models of the standard of 50 ohms. Typically produced with an impedance of 50 ohms and work up to 11GHz. Some versions may have a boundary frequency to 18GHz.

Scope of n connections - Local networks, measuring equipment, broadcasting, satellite and military communication equipment. Plugs, sockets, terminators and protective caps, adapters are produced.

TNC connectors represent the BNC version of connectors with unifying characteristics. Configurations of cables and their installation procedures are very similar to the BNC series. Plugs, sockets, terminators and protective caps, adapters are made.

UHF connectors It was invented in 1930. Clark Kartzenbush (Amphenol) for the broadcasting industry. UHF plug, according to the military list, is usually called PL-259. UHF Connotoras have a screw connection and are characterized by impedance impetus. In this regard, their use is limited to 300mhz frequencies. These connectors relate to the category of inexpensive and are used mainly for low-frequency range communication equipment (SV). Sustainably work up to 300-400MHz with minor losses. UHF connectors are popular and economical - are used if the compliance of the resistance is not required. The M and UHF series are close in structure and efficiency, but are not interchangeable without adapter (adapter) due to different screws at the connection site. Made under cables with a diameter of 5 to 18 mm. Machine plugs, nests, adapters.

Mini UHF. Compact and easy connectors designed specifically for applications requiring miniaturization. Characterized by the impermanence of impedance and satisfactorily operate at frequencies up to 2 GHz and voltage up to 335 V, but have a limit on the transmitted power up to 100 W. Available for a coaxial cable with a diameter of up to 6.25mm. Have a high reliability. Plugs, nelezda, adapters.

RCA connectors Standard widely used in audio and video equipment. The name of the RCA occurred from the name Radio Corporation of America, which offered this type of connectivity in the early 1940s to connect phonographs to amplifiers. In Russian, a similar type of RF connector is often called "tulip", or "bells".

SMA connector(sub miniature type A) - developed in 1960. Initially, for a semi-vegetable cable 0.141 inches (RG-402). Connectors are designed for impedance 50 ohms, some precision versions can work up to 26.5GHz. The maximum operating frequency for cable connector is determined by the type of cable. SMA have a wide range of applications where the key parameters are dimensions and a boundary frequency. Used in many microwave devices (coaxial-waveguide and micro striped transitions, amplifiers, attenuators, filters, mixers setting generators and switches). Connectors are made of stainless steel, have increased reliability and mechanical strength. Complies with the specifications: MIL-C-39012. Frequency range - from 0 to 12 GHz. Plugs, nelezda, adapters.

FME connectors Used to connect terminal devices (mobile systems, radio forms, cellular terminals, etc.) with mobile antennas and adapted to UHF, MINI, MINI, TNC, BNC and N. Constructive connector (rotating nipple) allows it to rotate 360 ° followed by fixing the connection with a cape nut, which ensures flexibility when connecting mobile communication equipment. FME connectors are designed for impedance 50 Ohm and are designed to work at frequencies up to 2 GHz inclusive. There are modifications for coaxial cables RG-58 / U, RG-59 / U, RG-174 / U.

SMB connectors (Subminiature Connector, Type B) These are miniature connectors designed to work at frequencies to 4GHz. Little size and connections make a SMB perfect connector. Used in telecommunications, testing equipment and tools, in satellite communications, in navigation instruments. We are manufactured with 50-ohm and 75-ohm impedance, can work in a wide frequency band up to 4 GHz. Typical use of SMB - inter-blank and inter-block connections for transmitting RF and digital signals, telecommunication and test equipment, high-precision electronic tools. Release plugs, sockets, adapters for both crimping and for fastening a cable using a soldering.

MCX connectors Microminiature connectors embedded in the 1980s and corresponding to the requirements of the European standard CECC 22220. have the same central contact and insulator sizes as SMB connectors, but the outer diameter of the socket is 0.14 inches, which is 30% less than that of the connectors SMB series. This feature provides designers with the opportunity to use them where there is particularly high requirements for saving space and weight. The snap-down mechanism provides the ability to quickly connect / disconnect. MCX is available with an impedance of 50 and 75 ohms and are capable of working with a low reflection at frequencies to 6 GHz and 1.5 GHz, respectively.

MMCX connectors(Reduced MCX option) is 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 microminiature connectors with a snap-in mechanism that allows rotation of 360 °, which ensures flexibility when used with printed circuit boards. MMCX Connectors meet the requirements of the European CECC22000 Specification. This family of devices are an interconnect system with an impedance of 50 ohms and has broadband parameters with a low reflection up to 6 GHz, providing high signal-to-signal. Different type connectors are manufactured: cable, for surface mounting and end (comb) for printed mounting.

The main types of RF connectors and their working frequencies Plate from the Internet, the right places. My comments are below.
connector	working strip	connector	working 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 an unknown compiler of this table is manifested in the misunderstanding of the material he is trying to systematize. See for yourself:

1. BNC and TNC connectors are the same connector, the difference only in the fixing nut, which does not affect electrical parameters and maybe (and sometimes!) Even plastic.

2. SMA and SMB connectors are the same.

3. F - only "MALE" only has satisfactory parameters in the specified range. Most F (F) - begins to spoil the coordination at 600 MHz. N.B. There are f (f) special "bottling" (blue dielectric), they correspond to the table.

4. Most UHF connectors imported to Russia from China - poor quality and work well up to 60 MHz. Small dances with tambourine allow them to use up to 150 MHz. Pay attention to the UHF socket standing on the transceiver or the CSW meter, these connectors are frequency-composit and their wave resistance is given to 50 ohms.

Adherents of the UHF connector - abbreviated translation of the comparative testing of the connector UHF and N.

Chris Arthur ML. / VK3JEG - http://www.qsl.net/vk3jeg/pl259tst.html :) pls don't kick me, When a Mistake.

Frequency analysis of the UHF connector.

A closer look at the connector with an abnormal impedance - PL-259 and SO-239.

Introduction The UHF connector gained its concept in the early 1930s, when VHF / UHF technology was relatively young. The progenitors of the UHF connectors in many cases were radio amateur radio amateurs, most of its engineering or technical education, which began experimenting and operating with the VHF range in about 1926.

A little later, the studies in FM radio and TV began, as a result, the name of the UHF named this connector.

At that time, mathematical models of the field and EMF were quite defined by J. Maxvel and his followers. Nevertheless, there were problems of physical nature - tools and applied science developed not so quickly. The results of this period of development of radio and telecommunications were often obtained by experimental methods of samples and errors, using tools that are now treated.

Purpose . Show problems associated with RF connector with non-corned impedance.

(I translate 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 Felow Radio Amateurs with Information That Is Not Readily Available. Characterisation 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 Adaptors 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 Analyser. In this case I employed the use of the Royal Melbourne Institute of Technology "s Wiltron model 360B Vector Network Analyser. 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 Analyser 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 50 Ohm Test Lines and Adaptors 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 ARE QUITE EXPENSIVE (Around $ 1000AU EA).

UHF Type Adaptors Used in Comparison

2 X FEMALE NO PL-259 Adaptors (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 Adaptors (Simulating the Line Connectors, N Males)

1 x FEMALE TO FEMALE N ADAPTOR (RADIO AND ANTENNA Connections, N FM "S)

Results Two of the N to PL-259 "S WERE MATED WERE 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 Adaptors 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 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 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 Real 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 viewable 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 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 TRANSMISION 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 WHER WE SEE A LOSS IN THE ORDER OF 1.0 DB, THIS EQUATES TO A TRANSMISION LOSS OF AROUND 6 WATTS 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 Havesed 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 Sometime 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 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 Utilisation 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 BUTI HAS THE DISADVANTAGE OF BEING LESS RUGGED. In The End, One Should Always Check With The Manufactures Specifications.