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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26 views

Troubleshooting NOAA double cross antenna

I've been trying to recive NOAA automatic picture transmission (APT) pictures for a year now. I never got a picture with V-dipole, so I decided to build a double cross antenna. I used 75 ohm coax ...
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26 views

Jacket diameter of coaxial cable : how to read those documentations?

Before anything: I am not an electrical engineer: I don't know very much coaxial cables (just the very basics). I need to do some orders of magnitude calculation of heat transport of typical coaxial ...
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29 views

Coaxial cable terminology : how to read?

I need to understand the nomenclature used for coaxial cable. For example: UT-085-SS-SS, or UT-085-SS, or UT-085-NbTi As far as I understood, the number 085 here is the total diameter of the cable ...
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53 views

Coaxial cable and lower frequencies

Does a coaxial cable have any advantages in transmitting lower frequencies? If it does, what are those advantages?
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26 views

Timebase Ground-Loops - why place the isolation transformer at the input instead of the output?

In the course of investigating the construction of a home-made 10 MHz lab frequency reference I wondered if the output from such a reference should be isolated. I came across a small article about ...
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68 views

Making my own coaxial hardline

I need about 50mm of coax hardline. I don't have any at home, but I do have a lathe, some copper, and some teflon stock. Can I make my own coax hardline on the lathe? According to my calculations, ...
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2answers
56 views

High voltage coaxial probe measurements

I am designing a high voltage motor controller and I want to validate the switching circuitry to ensure there's no excessive ringing behavior. I had an idea to use something like an SMA or u.FL ...
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54 views

Coax cable loss drops by approximately 0.5 dB at a specific frequency

I am trying to understand why the measured loss of our coaxial cable is decreased exactly at a specific frequency. My understanding is that the loss should be linear with the frequency. However, there ...
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64 views

What would you call a cable which combines both a coaxial transmission line and regular conductors?

I'm looking for a cable that can carry both dual supply (+5V and -5V at <100mA) DC power and a relatively high bandwidth analog signal. The intended application is powering the amplifier of an ...
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3answers
79 views

KiCAD: Triaxial Connector Footprint from Drawing

I am planning to use a PCB-mount triaxial connector, CBBJR79TL, in a design for a laboratory prototype. Making reference to the "recommended mtg hole pattern" section from the CBBJR79TL drawing, I ...
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25 views

Does DiSEqC require a DC bias?

The DiSEqC (Di[gital] S[attelite] Eq[uipment] C[ontrol] specification (bus_spec.pdf within https://www.eutelsat.com/files/PDF/DiSEqC-documentation.zip) describes a tone-based serial data bus that can ...
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105 views

How to construct an SMA feedline for a horn antenna

I'm constructing an sma coax to waveguide transition for a horn antenna. Here's a cross-sectional view of what the device will look like I can 3d print the waveguide portion (I use a conductive paint ...
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4answers
84 views

Coax characteristic impedance measurement

How is physically possible to get the value of the characteristic impedance of a certain coaxial cable? Precisely, in my case I have a coax of 50Ohm impedance, and I need to cut it and connect some ...
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1answer
23 views

SMB Connector Grounding for S/PDIF Coax

I'm transmitting coax level S/PDIF over an SMB connector, and I'm wondering if the "body" pins (all pins that aren't the center) should be left floating, or if they should be connected to ground. As ...
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94 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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64 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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1answer
52 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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1answer
64 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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1answer
55 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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1answer
278 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
1k 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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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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1answer
68 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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1answer
60 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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125 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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65 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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1answer
157 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
491 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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311 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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1answer
48 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
521 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
630 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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165 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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101 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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7k 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
898 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
86 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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157 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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1answer
76 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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781 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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233 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
926 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
94 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
420 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
591 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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3answers
964 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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116 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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529 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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205 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
405 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 ...