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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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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3answers
89 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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24 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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70 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
59 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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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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96 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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78 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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258 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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245 views

Coax cable + BNC temperature response

I have a couple of cheap prefabricated 1m 50 Ohm cables terminated with male BNC connectors. These connect to a device in an environmental test chamber which is cycling between 5 degC and 60 degC. I ...
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363 views

Push-on coaxial connector with RF leakage performance comparable to threaded-coax connector?

In examining the performance characteristics of the push-on SMP connector I've noticed that the RF leakage is at best -80dB @ 3 GHz and then continues to degrade as the frequency increases to -65 dB @...
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2answers
205 views

How does current flow inside a grounded coax shield?

I have been trying to reconcile the fact that current flows on the inside of a coax shield with the common practice of grounding the shield. These ideas seem contradictory at the moment. For a 2-wire ...
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26 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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55 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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56 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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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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1answer
61 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
63 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
177 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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1answer
50 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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117 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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3answers
414 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)...