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Questions tagged [coaxial-cable]

Questions about coaxial cables, including different types of cable, connectors, adapters, and other topics.

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2
votes
1answer
46 views

can i convert an FM coaxial antenna to just speaker wire?

I have a Sony MHC-GX450 compact mini stereo system. The connector for the FM antenna is coaxial, and is labeled 75 Ω. I'm wondering if somehow I can use speaker wire for the FM antenna.
4
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3answers
146 views

RF ground confusion

I'm a bit confused by RF grounding. Let's take a HF 1/4 wave vertical antenna for example. When current flows through the centre of the coax to the antenna, my understanding is that the current then ...
1
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1answer
32 views

Velocity Factors of Military Spec Coaxial Cables. Are they accurate and consistent in the real world?

Like the heading says, I would be very interested in any real life data collected by fellow radio enthusiasts in regard to the velocity factors stated for mil spec coaxial cable, eg. RG213, RG58. ...
5
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5answers
235 views

Grounding a vertical antenna from a balcony

I have a multiband vertical antenna mounted onto the railings of my balcony apartment high up on the 6th floor of an apartment building. The antenna is not grounded. This antenna comes without radials....
3
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3answers
4k views

Choke at antenna and feedpoint?

I'm planning on putting up a G5RV. From the ladder line I connect 5m coax to the shack; would it be worth doing a common mode current choke at both the antenna feedpoint and the coax feedpoint? (I ...
1
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0answers
38 views

J Pole, what is the best way to deal with Common Mode Current? [duplicate]

I am planning on utilising a ferrite choke on a J Pole antenna for CMC. Placement directly on the feedpoint poses possible mechanical restraints. Is it okay to place it a quarter wave down the coaxial ...
5
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1answer
11k views

How to calculate single-stub match (general case)?

I'm trying to build a 1/2 wave "Coaxial J-Pole" antenna, similar to what is described here: Such an antenna would be great for stringing up in a tree when operating remotely, no tuner needed. The ...
2
votes
1answer
42 views

One cable two different radios

I have a GMRS radio and VHF/UHF radio in car. I have an antenna mount and cable installed. I install appropriate antenna for the radio in use and manually remove and attach cable to matching radio. It’...
2
votes
1answer
88 views

When to use air dielectric cables for antenna installation

I'm putting up antennas on a tower, and have a couple of 7/8" cables style on hand. One is Hj5-50 air dielectric cable and the other AVA5-50 "Virtual Air" cable. I notice that the HJ5 ...
4
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3answers
2k views

It it really useful to terminate unused 75Ω outputs on a coax splitter?

When discussing improvements to my home HDTV Antenna/distribution system a colleague brought up the need to terminate all coax, even unused splitter ports. My understanding of the way terminator ...
3
votes
2answers
74 views

Ground plane reflects RF or brings it to ground

I'm still confused with the purpose of a ground plane purpose in an antenna. My understanding is this. If an antenna is perfectly balanced, there will be no common-mode currents going to ground. If an ...
4
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3answers
140 views

When a dipole antenna is fed via coax, what powers the ground-side of the dipole?

I've been trying to understand how dipole antennas work, and I believe I understand the basics when they're fed via a balanced feed line. In fact, every dipole physics YouTube video and web page I can ...
1
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1answer
66 views

Replacing a N-connector with SMA, easy?

I purchased a cell phone booster for the cottage that came with an external yagi. Since its important to get the antenna as far away as possible from the indoor omni, the yagi has about 25 meters of ...
3
votes
1answer
466 views

Recomended coax for 100ft (2m/70cm)

I recently moved to another house. My setup's current coax is 50ft/RG8x/PL259 (bought in 2018), but it is not enough for connecting my antenna to where I want to place the radio. I believe that 50ft ...
8
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4answers
15k views

How is a 1:1 current balun different from a choke?

I have a 10m dipole and am going to feed it with 50 ohm unbalanced feed line (coax). My understanding is the feed point of this style antenna is about 50-75 ohms, and since it is a balanced antenna I'...
3
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3answers
9k views

Using 75 Ω instead of 50 Ω coax feed

Can I replace my old 50 Ω coax with RG6? It's cheaper and less loss at VHF/UHF. I would match by L/2 multiples of coax to repeat input and output impedance or L/C matching networks at each end. Is ...
1
vote
1answer
51 views

How do I connect a homebrew antenna using RX-8 to a Yaesu FT-70DR (SMA)?

I made an 2m / 70cm tape measure antenna using RG-8 coax. That part was quite a bit of fun and went fine. But when I tried to connect the coax to my Yaesu FT-70DR, the copper core of the RG-8 was too ...
1
vote
1answer
399 views

Combining/splitting three different RF signals

Not being so fluent in RF, I decided to ask here if my current approach seems doable or how one would try to achieve something like this: I'm doing research and deciding on an approach for my proto-...
3
votes
1answer
620 views

Trying to understand the work of 4:1 coax balun

Let's consider the following picture (source): When current passes the half-wavelength matching section it changes the phase to the opposite, this is why we get +V and -V in the feed point, 2V ...
0
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2answers
256 views

How to use 75ohm (RG6) coax?

I know that there have been many similar threads on this, but I still need clarification. At the moment, the only thing I have is a 500' roll of RG-6 and a (very) tight budget, and I should be ...
12
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2answers
4k views

Is there an optimum Antenna Feedline Length for mobile installations?

I bought a ham radio antenna mounting kit for my car that includes ~16' of coax. One end has a trunk lip NMO antenna mount, the other end has a re-solderable PL-259. I asked the sales person if it is ...
0
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3answers
111 views

Weatherproofing coax connection to balun

How should a coax-to-housing connection like this be weatherproofed? It doesn't seem like taping is going to do much good here
0
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1answer
29 views

Hustler BTV coax overhead run

I'm pretty sure this will be fine but thought I'd ask. A Hustler 5btv antenna, the coax from the feedpoint (ground mounted) runs for 3 or 4 meters along with the radials, and am thinking of going up ...
4
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2answers
329 views

How do I know if my coax connectors are good?

In installed a couple of compression style PL-259 connectors to the ends of RG8/U FOAM coax. It's about 16 feet in length. Here is an example of one of the connectors: How do I know if the coax is &...
0
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2answers
2k views

Which cable is better for ham radio antenna? RG58, RG59, or RG6? [closed]

Which cable is better for ham radio antenna? RG 58, RG 59, or RG 6? Based on [1], RG6 has lower signal loss. So, is RG 6 a better cable? Or there are no differences? [1] https://sewelldirect.com/blogs/...
3
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1answer
87 views

How to deal with foil shield when adding a connector?

I want to crimp a connector onto some RG58 A/U cable. The cable has a foil shield under the braided shield. What's the recommended way to deal with the foil? Should I treat it just like the braided ...
5
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4answers
341 views

50Ohm Coax presents 50 Ohms of impedance on which frequency?

Either there's a simple answer that I'm not finding in a spec sheet somewhere, or, I'm asking the wrong question!
1
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1answer
387 views

440MHz collinear dipole array - suitable coax?

friends! Finally found my next antenna project..a collinear dipole array for the 70cm US ham band. The general idea: (image courtesy https://link.springer.com/referenceworkentry/10.1007%2F978-981-...
3
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2answers
193 views

Supershield or Superscreen coax: Does it exist? What is its common name?

I'm sure this seems like a Google question, but I've BTDT and come up empty. The problem I'm trying to solve is to obtain cables that are as "leak proof" as possible. Tried Pasternak "...
1
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1answer
108 views

What is the maximum antenna cable length allowed in GNSS application?

I am beginner in designing GNSS receiver design and facing concern while testing the high precision GNSS survey.I am using GNSS survey grade antenna for my GNSS receiver application testing, the ...
1
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2answers
776 views

What is the best type of feedline for a base UHF VHF ground plane antenna with a distance of around 50-75 feet of coax?

I'm going to be putting up a Comet GP6 UHF/VHF Ground Plane Antenna. It will be chimney mounted to a mast, and the total height is around 40 ft. The upper half of the chimney starts at the first ...
7
votes
2answers
344 views

What does an antenna analyzer tell me about these coaxial cables?

Note: more measurements added after graphs below I recently acquired a RigExpert antenna analyzer and I am trying to learn how to use it to test cables. I took two cables to start with to try and ...
2
votes
1answer
105 views

Glass Block Pass Through

In my future shack I will have glass block windows consisting of 6 x 8 blocks and a 6 x 16 vent. I've been searching, but cannot find the best solution to pass coax through the windows. I've thought ...
3
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1answer
141 views

Do the Horizontal Conductors of a Ground Plane Antenna Adequately Decouple Its Feedline?

A NEC4.2 analysis of this configuration may reveal an unexpected truth about this...
7
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5answers
732 views

Coax fed dipole: shield goes to one side, yet is grounded via chassis line to Earth

Suppose I have a coax-fed half-wave dipole antenna. The coax shield goes to one side of the antenna, the center conductor to the other side. The transceiver's chassis is connected (via the coax ...
2
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2answers
138 views

coax switches for HF

Like many hams I have several radios and several antennas. instead of constantly connecting and disconnecting coax cables I would like to feed several antennas in to some type of switch so I can ...
11
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4answers
2k views

Is "low loss" cable required for HF?

I use RG-58 for all my HF antennas, since it's light, flexible, convenient, and cheap. And super easy to choke. Whenever I have a problem I just loop a few turns of it on a ferrite core and the ...
4
votes
4answers
487 views

Soldering PL-259.. with a torch?

I came across this article about torch soldering PL-259 coax connectors. It seemed like a good idea since the body needs a lot of heat to get solder to flow into the holes. It's a little vague when ...
0
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4answers
404 views

Using cable coax rg 11

I am using RG 11 coax connected to receive radio. Center wire to one post shield to other post. Can it be used as a long wire antenna by it's self?
5
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4answers
846 views

Testing for 'Bad' Coax

I have a lot of 'donated' coax that has been given to me with unknown provenance. I'm wondering what things I can do that can determine whether I keep it or send to the tip? Some of the things I have ...
2
votes
1answer
913 views

300 ohm to 50 Balun at antenna feedpoint, or near receiver?

If I build a folded dipole, it will have an impedance close to 300 ohms. I have to match this impedance to the 50 ohms of my transceiver. I know many people match that impedance with varying lengths ...
1
vote
1answer
587 views

SO-239 (UHF) vs N connector power handling on 160m

I am curious how much CW power an N connector or SO-239 connector will handle on such a low frequency like 160m band. I know on VHF they will probably handle about 800W before getting too warm. I ...
2
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2answers
228 views

Will using a 1:1 balun at the feedpoint of a center feed dipole result in no common mode current on the outside of the coax?

Will using a 1:1 balun at the feedpoint of a center-fed dipole when using coax result in no common mode current on the outside of the coax ?
0
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2answers
1k views

Understanding RG6-75 ohm Cable Impedance

Here is my measurement to a piece of RG6 cable. It is around 30cm cable. On the shield is written COAXIAL CABLE 5C-2V 75 ohm. From my measurement I got data as below: From that table, we can see that ...
5
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2answers
1k views

Why is my calculation for added length of coax for a double cross antenna different to everyone else's?

I'm an amateur amateur radio enthusiast finally building my own antenna, and have decided on a double cross antenna, with the goal of pulling data from NOAA satellites. Four coax cables, two of ...
2
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3answers
895 views

VHF 50 Ω Antenna Over 75 Ω TV Coax

I have a 50 Ω VHF airband antenna which I’m planning to install in my loft, for use with a RaspberryPi-based RTLSDR scanner/receiver. I already have a UK-standard UHF/Freeview antenna using standard ...
10
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4answers
208 views

Why are there so many coaxial cable impedances?

Why do we have 50, 75, 62 and 92 Ω coaxial cable, to name a few? Why not just one standardised cable? Is there some technical reason or did Mr. Coax and Mr. Cable have a disagreement, like Mr. Tesla ...
8
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3answers
5k views

How do I extend broken coaxial cable?

I have a piece of 75 ohm coaxial cable of unknown type (outer diameter is around 7 mm) which has developed a breakage in the center conductor (which is stranded). This cable is an adapter cable which ...
6
votes
4answers
683 views

Weather-proofing antenna connections

Here's a problem: you buy a fancy new vertical for a fair bit of coin, but there's no coax connector on the thing. There are just screw terminals. You need to attach coax to it, but in such a way ...
2
votes
1answer
101 views

Should I run RG8x / mini8 zip tied to a cat 5e ethernet cable?

I'm running a feed line from the end of my amplifier to the antenna for HF transmissions. I'm using RG8x / mini 8. There's an existing pathway through my house I'd like to use that has a cat 5e ...