Questions tagged [coax]

Coaxial cable, or coax, is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield.

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37 views

Dipole Antenna impedance and feed point, what is the effect of long distance to coax connector?

I have a folded dipole being made with a pair of twisted wires where each wire is 1/4 λ long and the dipole is constructed by twisting the centers of the wires so that the twisted pair is ...
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22 views

Permittivity measurement using open-ended coaxial probe

I am trying to understand how the complex permittivity of liquids can be measured using an open-ended coaxial probe. For this kind of measurement, we put a open-ended coaxial line into the liquid ...
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30 views

How to make a power supply cable for a 10.5V 4.3A laptop OR how much higher voltage can I use

Let me preface this by saying I've spent countless hours researching and learning what I can about electronics before asking this, and I cannot find a clear answer to this. So sorry if this seems like ...
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41 views

Leakage Inductance Coaxial Cable

I do not understand how a particular parasitic effect is model. I have read that on a coaxial cable there is a problem due to the fact that the external conductor's magnetic field crosses the air ...
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61 views

Identification of coax connector

This is the antenna end of the car phone antenna cable in a 1983 Mercedes 300D (w123 chassis). The other end of the cable is the usual UHF connector. The metal part of the connector is 15/32" in ...
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1answer
50 views

How to properly terminate this circuit

I have a 50 ohm BNC cable which connects to a coaxial connector on a PCB. I want to invert the signal from the cable with an op amp. If I use the top circuit from the image, will the cable be ...
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53 views

Cutoff or Corner Frequency for Coax Cable

I'm trying to understand better what the significance of the cutoff frequency for coax cables is. I have a case where a cable is considered for use at frequencies up to 3% higher than the manufacturer'...
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3answers
536 views

How does Internet communication work on a coaxial cable?

In buildings, it is common for the same cable (coax) to be used for pay-TV and the Internet. It makes sense that I can transmit several TV channels on the same cable, since it can be modulated by the ...
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42 views

Wifi coaxial cable type unknown

Quick question, I was unable to identify the coaxial cable type used in wifi devices(routers ,tablets,etc.) , very thin grey cable approximately 1mm in outer diameter, I need to know the type so I can ...
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99 views

adding an antenna to a toy PCB, where can I ground it? is the negative battery cable ok?

I want to replace the antenna on my toy quadcopter with a better one, to improve reception. On toy quadcopters the antenna is just a simple wire soldered to the quadcopter circuit board (with no ...
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33 views

Media converter - Coax or Twisted Pair [duplicate]

I am working on a Double Leaf Bascule bridge spanning across a river that needs rehabilitated. The bridge is driven from a ControlLogix PLC consisting of 4 racks on the nearside span. Power/control is ...
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40 views

THINNET 10BASE2 Network using RG-58 Coaxial Cable operating frequecy?

I am trying to figure out what the signal frequency of a 10BASE2 network is. Specifically the frequency of the signal being carried over coaxial cable. Data transfer is 10Mbps and the network adapters ...
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47 views

Simple question regarding coaxial cable

I have a coaxial cable whose length is $$L=10m$$, working at $$f=1GHz$$ frequency and i need to determine it's attenuation coefficient (if that is correct term), however i cannot find any relationship ...
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69 views

What are the s-parameters of a rg58 coaxial cable?

Can a the s-parameters of a rg58 coaxial transmission line be calculated. If yes, what are they?
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49 views

Coax cable shielding understanding at AC

I know that AC changes its polarity once a cycle. We use coaxial cable for protecting the signal from magnetic interference. But if the cycle is negative then it it will flow in the shielding, won't ...
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73 views

How to quantify the cable impedance for common mode voltages?

Since a coaxial cable is not twisted, in the case of a common-mode interference the positive and negative lines will pick up different voltages. This unbalanced impedance nature of the cable can be ...
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2answers
257 views

Cut-off frequency in coaxial cable

The cut-off frequency of an RL circuit is described by the following equation: $$f = \frac{R}{2\pi L}$$ where R is the resistance of the circuit and L is the inductance. Applying this equation to a ...
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207 views

Effects of impedance mismatch on RF signals from antenna

I'm building an antenna array that operates at high frequencies (around 2 GHz). I want to use a SDR dongle that has a 75 ohm input impedance as receiver, I've also bought the coax cable, a 4 way ...
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41 views

AC Power Splitter and Regulator

Is there a charging cable which splits into two? One of the split cable will have DC 12v 3a with a male coaxial 5.5mm x 9.5mm The other split cable will have DC 5v 3a with a USB Micro. Does this ...
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3answers
260 views

Coaxial cable: how is it possible to define a conductance?

I have a coaxial cable with internal conductor of radius r1 and external conductor of radii r2 and r3. The material of the conductors has a conductivity \$\sigma_1\$. Between the conductors there is a ...
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1answer
244 views

Why are there 3 conductors on a coaxial BNC connector and 4 conductors on a triaxial BNC connector?

From what I understand, a BNC connector and it's cable has an inner conductor to route the signal and an outer conductor(cylindrical) to provide a shield to inner conductor and to provide a return ...
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2answers
121 views

calibrating vector network analyzer with \$75\Omega \$ coax

I am new to electronics and I just began to use a vector notwork analyzer for some measurements. I calibrated my vector network analyzer with both ports connected to 50\$ \Omega \$ coax cables with ...
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1answer
85 views

Power over coax standard

We are specifying a system to use power over coaxial cable, that will transmit SDI video. Is there any standard (IEEE or otherwise) for implementing it?
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3k views

Why do I have 2 coaxial cables? [closed]

In my house there is a wall outlet with 2 coaxial cables coming out. Why 2? I saw there some sort of service that needs double bandwidth?
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1answer
565 views

How does this impedance matching circuit work? How to simulate it correctly in SPICE?

I have a schematic for a current sensing circuit using a dedicated TI differential amplifier part for current sensing applications. The schematic also includes an "impedance matching" part for ...
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1answer
64 views

Help identifying this RF connector Icom FR4000

J1 is a coax push-in connector from an Icom FR4000 repeater. The gray wire is a thin piece of coax, unsure of the actual type (RG316?). Not a common connector but I've seen it before. Doesn't click in,...
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101 views

MoCa - Ethernet over Coaxial

This is specifically a high-level hobbyist question, I'm not really looking for schematics or anything of the sort. To deliver Ethernet over Coaxial, what sort of high-level designs or common issues ...
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67 views

is it safe to have coaxial cables set up like this? [closed]

Wondering if this set up poses any harm or anything
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476 views

Soldering RG-405 coaxial cable directly to PCB pads meant for U.FL connector

Is there an ideal method to solder a bare cable to a PCB for microwave (5-6GHz) signals? The U.FL connectors that are normally used in this application are terrible, and there aren't many (or any) ...
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140 views

F type female to SMA male adapter impedance question

I have a coaxial cable that I need to connect to a SMA female connect. The impedance of the cable is 75 ohms, and from online the SMA female connect is 50 ohms. Online there are a few places that sell ...
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4answers
616 views

How is “signal strength” characterized on a coaxial cable?

I've come across the Shannon-Hartley theorem, so I assume that a "signal" must have some notion of strength or "power" that can be referenced to some noise level (and whose power can be varied at the ...
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2answers
82 views

High-Speed electronics - Reflections in T-intersection

I'm currently attending a course on "experimental problem solving" and we just started talking about TDR (time domain reflectometry). I do understand that reflections occur whenever there is a change ...
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3answers
288 views

Would an unconnected coaxial cable act as a wifi antenna?

I am building an underwater drone and I connect to it via wifi when it is at the surface. The wifi signal often gets blocked by water waves though. I don't really want to have another penetration of ...
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1answer
385 views

Coaxial cable for the DC-10GHZ range

I am trying to understand how to choose a coaxial cable (for my current application, I need a 50Ohm coaxial cable that works reasonably well in the DC-10GHZ range). According to the table in section "...
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621 views

Function Generator, BNC T and Termination

I have a question regarding best practices for function generator to circuit/scope connection. I recently had an issue chasing down excessive ringing on square wave signals coming from a function ...
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110 views

What are these coax connectors called?

These are the connectors you can typically find on the back of stereo head units in cars, to connect the FM radio antenna. I measured the external diameter at ~10mm. You can easily find a ton of ...
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502 views

Is a single FET a good way to drive a 100kHz signal through short coax?

I'm trying to transfer a small (1V) variable frequency signal over about a metre of coax. I'm not interested in anything above 100 kHz. One thing to note is that my signal already comes with a +...
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2answers
146 views

Feeding multiple 50 ohm terminated outputs from a single 50 ohm source without signal degradation

I'm having an issue in which I have a trigger from an instrument meant to be sent to another instrument with a 50 ohm termination. I want to use that signal to distribute it to several outputs that ...
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1answer
304 views

Coaxial DC power cable for switching AC adapter required?

Recently the DC cable from my AC/DC adapter to my laptop broke. I removed the broken section and it works again. Now the cable is too short for my taste and I would like to replace it. I heard from an ...
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75 views

I need an aerial adaptor for my 4G modem. What are the names of these types of coax connectors?

I have a 'Mifi'™ 4G modem. I ordered an external aerial for it, but the diameter of the connector is about four times the size I need. I want to buy an adaptor, but I don't know what search terms to ...
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Are there types of standard coaxial cable with a propagation velocity of 0.9c? What would be the application?

Reading this answer I was surprised to hear that there are "excellent" kinds of coaxial cable with a propagation speed of 0.9c; 90% the speed of light. The bargain basement number is about 2/3c, and ...
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112 views

Coaxial cables vs zip cords for unbalanced signalling

I was watching a short tutorial video about balanced audio, and the guy claims for unbalanced transmission even there is shield in coax cable "hum and noise still gets true". But in wiki it says: "...
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182 views

AC signal to a coaxial cable

I am quite new in this field and I started recently by reading the first books in electrical engineering where I learned the concept of current, voltage, impedance, reactance (inductive and capacitive)...
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159 views

Role of Coax Cable in bringing TV signal to our TV sets

We know that we receive the programs/shows of TV Channels from the producers of programs through CATV Service providers (almost obsolete, just wanted to get clarified on its working process) DTH ...
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269 views

What tool is used to cut back the outer jacket and dielectric of a coaxial cable?

I would like to assemble a few SMA connectors on 0.086" semirigid coaxial cable. Here is an image of the assembly instructions on one such part (Amphenol 901-9723). As you can see, the outer jacket ...
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2answers
2k views

Why is the bunny-ears TV antenna normally connected to 300 ohm twin lead?

The bunny-ears antenna is similar to a dipole, which has an impedance of ~75 ohm. Why are the elements of such antennas connected directly to 300 ohm ladder line? Wouldn't that cause mismatch losses (...
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143 views

How does single coax wire transmit a lot of information? [closed]

I have a coax cable entering my house. The cable (from the Cable company), splits into a Cable modem (for computer network) and into a DVR (a.k.a. cable box). How can a single coax wire contain ...
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139 views

Short Coax for carrying low frequencies (120kHz) - does it matter if 50 Ohm or 75 Ohm?

I'm using coax to carry signals whose highest frequency component is 120kHz over a distance of 2 or 3 meters. Does it matter whether the characteristic impedance is 50 or 75 Ohms? My feeling is it ...
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502 views

Shielded breadboard jumper cable wires

Does it exist a shielded version of 2.54mm pitch breadboard jumper cable wires? Thin flexible wires, Gauge AWG 24-28. I want use shielded wires for JTAG cable, to reduce electrical noise from ...
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933 views

EM Waves in Coaxial Cable

I've been educated that a coaxial cable has two conductors: inner or the central core and the outer conductor or the sheath. Both these carry currents but in opposite directions. The AC current ...