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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33 views

Best way to connect coax along a microstrip

I have an open-ended (stripped, if needed) coaxial cable that I would like to use to insert a signal into a microstrip. The circuit (operating at ca. 18 GHz) however, is made in a way where I can't ...
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41 views

Antenna Attenuation, Gain and RSSI calculation

I am using a RAK7258 LoRa gateway operating at EU-868MHz. I am looking to have the gateway and the antenna on each side of a wall (gateway inside, antenna outside) and receive some packets from some ...
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3answers
204 views

Why is a coaxial cable unbalanced?

Let's consider a coaxial cable which supplies a dipole antenna. My reference for all my statements is here. My reference says: Note that the current along a transmission line should be of equal ...
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28 views

Coax or STP input to the Deserializer

I have this MAX9278 deserializer. I am planning to give Shielded Twisted Pair (STP) input to the IN+ and IN- pins of the deserializer instead of COAX input. Can someone help me to let me know what ...
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35 views

How to identify a coax connector vs twisted pair connector

I need to have a connector that will bring in COAX input to my PCB. I have this Rosenberger HSD Connector Catalog. On page 33, "99S12D-40MA5-y" - is this connector a twisted pair connector ...
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1answer
32 views

12 DC Power 3.5A to TV via Antenna Cable [closed]

I am looking for a single connection to a TV which is powered by 12Vdc 3.5A Max, I would like to power the TV via the coaxial cable and also use the coax cable as an antenna input. I am looking for ...
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1answer
69 views

Problems with small signals through BNC connectors?

I have a 120kHz signal from a transducer with peak to peak values of typically 40mV being carried over coax cable and connected at both ends via BNC connectors. Most of the time this seems to work, ...
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39 views

How does one properly strip coaxial cable to nonstandard strip lengths?

For my job, I need to put SHV connectors on a couple lengths of RG-59. I have the cable, the connector, and the crimping tool, but I've hit a snag: I don't have the slightest idea how to properly ...
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1answer
43 views

Power loss due to mismatch impedance connector in coaxial line

Not being an electronics professional but face the following problem I hope you can help me. I would like to estimate the losses due to an impedance mismatch of connector used in wall-crossing of a ...
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1answer
43 views

Effect of coax mismatch

I have some accelerometer vibration sensors that pass into a cabinet. They use BNC type bulkheads. Several of the bulkheads got damaged. The original bulkheads are 50 ohm and the coax cables on either ...
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1answer
56 views

Female F connector diameter

I am having trouble finding the exact spec for the female F connector- what I need exactly is to know what is the connector diameter and the thread width. I found some info on Wikipedia, but its not ...
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28 views

Does using a push only plug for and F connector in a coaxial cable decreases the signal or adds noise?

I'm intending to find a replacement cable for my cablemodem unit. The existing cable that the phone company installed is a screw in terminal on both ends of the coaxial cable with one end connected to ...
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1answer
31 views

Protecting LEDs driven by pulse generator via coax cable

I am a student in physics, and I have a project where I need to pulse LEDs with short pulse widths. I have a SRS DG645 pulse generator and using these LEDs. I have an RG58 coax cable with a BNC ...
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1answer
39 views

signal types and wire types

I am trying to understand the selection criterion for choosing between a signal types and wire type out of the following: Signal types: Gnd reference uni-polar signal Gnd reference bi-polar signal ...
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1answer
32 views

Digital Communication \$T_x\$ and \$R_x\$ for Dish - Coaxial Cable - TV Setup

I have a question in mind regarding transmitters and receivers. Let's say we have a dish then a coaxial cable connecting our dish to the TV. Can we consider the Dish as a transmitter \$T_x\$ and the ...
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1answer
86 views

Op-amp input signal problem, mismatched

My signal generator drives a 50 ohm coaxial cable, terminated with a 50 ohm to ground at the input of a voltage amplifier. However, when I look at my input signal over frequency, it doesn't behave as ...
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1answer
38 views

Can a differential probe and regular coax wire be connected safely to only one channel of scope using a tee connector?

I would like to ask if I can connect a differential probe and a coax wire through a tee connector to 1 channel of an oscilloscope, in order to take different DC measurements. The connection topology ...
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1answer
84 views

How does the shield of a coaxial cable work?

let's consider a coaxial cable with only two conductors (the core and the external metallic shield), and let's consider the case in which it propagates TEM mode at a certain frequency: My question is:...
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2answers
97 views

My simulated coax cut off frequency is way far off the calculated value

I used the lumped model to model a coax cable as a low pass filter in MATLAB. I also included ESR which is supposed to resemble the dielectric losses. I derived my transfer function from the circuit ...
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1answer
301 views

“To ground” or “not to ground” a coax to prevent RF ingress?

I have a communications system that connects a self-powered sensor circuit to a wall-powered processing/analyzing circuit by coax cable The coax reaches out about 60m, and it is matched/terminated at ...
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1answer
184 views

Measuring Current in Coax Cable Using Clamp on Current Probe

I once again find myself needing to measure the RF current in a coaxial cable. The signal in question is a high power (100W-1kW range) signal which is a stepped waveform with a 5MHz fundemental with ...
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1answer
66 views

Coax Cable Wave Impedance, Capacitive Load

I am studying the behaviour of cables over frequency, especially what a source sees, and have 2 Questions, as I did some simulations in LtSpice. As a model for the cable I used the "Lossy ...
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31 views

DC Coaxial Power Connector Rated for 20A

I have a 12V 20A power adapter seen here (https://www.ledwholesalers.com/v2/index.php?route=product/product&path=40_117&product_id=999). I would like to connect to this power supply, but my ...
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5answers
3k views

Coax cable - capacitive load

I still have an understanding problem with impedance matched coaxial cable and its behaviour. We do impedance matching to prevent reflections. How does my signal source see the whole cable? At a ...
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0answers
114 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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2answers
89 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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2answers
45 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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3answers
203 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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1answer
34 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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73 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
65 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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62 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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0answers
66 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
132 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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1answer
27 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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0answers
148 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
96 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
33 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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0answers
97 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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0answers
112 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
82 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
111 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
72 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
453 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
2k 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
118 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
75 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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1answer
293 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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1answer
106 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 ...