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7 votes
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Lightning protection by disconnect

what would be the theoretical disadvantages of such a disconnect system? Firstly, keep in mind that antennas don't cause lightning damage: grounds do. It's not clear from your description if your ...
Phil Frost - W8II's user avatar
7 votes
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Not-too-distant saltwater ground

With the canal 60 feet away it's not of much help. The objective with a monopole antenna is not just to have any ground connection, but to have a low-loss ground plane under the base of the antenna. ...
Phil Frost - W8II's user avatar
7 votes
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Why is it bad to put ground rods too close together?

Depends on how you want to look at it. Two ground rods spaced close together will be less effective than two rods with sufficient spacing, but still at least as effective as just one rod. So it's not ...
hobbs - KC2G's user avatar
  • 12.4k
7 votes

Why is it bad to put ground rods too close together?

One of my favorite lightning anecdotes is this story by W8JI. He had lightning strike a tree, blowing the bark off down the trunk, and making a huge hole in the ground. And then some 20 feet away, the ...
Phil Frost - W8II's user avatar
6 votes

What would be the easiest and most cost effective ground system for a startup UHF/VHF station

That statement is wrong on several levels. The antenna is DC grounded so no lighting arrestor is needed. A lightning arrester is needed, even if the antenna is DC ground. The arrester's job is to ...
Phil Frost - W8II's user avatar
6 votes

How to detect common-mode currents or “RF in the shack”?

Another way to detect current on the outside of coax is to run your hand up and down the coax wile an analyzer is connected , if you see a fluctuation on the meter then current is following on the ...
De Bohannan KC5ULU's user avatar
6 votes
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Is the ground on the back of the Icom IC-7300 an electrical or RF ground?

It's all of the above: an RF ground a 12 V power ground a lightning ground, for what it's worth a chassis ground to prevent "buzz" on the chassis if your shack 0V is not earthed The manual says to ...
tomnexus's user avatar
  • 11.2k
6 votes

Why are many ground radials preferable to a single ground stake buried 1m deep?

The purpose of the ground radials isn’t to ground the counterpoise. The purpose of a dense field of radials is to emulate as much as possible a perfect mirror surface, so that, to the far field, the ...
hotpaw2's user avatar
  • 13.3k
6 votes

How far from a cable entry point can the lighting suppressor be installed

The picture you have drawn suggests a lightning suppressor installed in this way will do little to nothing to protect your station. The suppressor does only one thing: it limits the maximum voltage ...
Phil Frost - W8II's user avatar
6 votes
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Where can one get a "listed" SO-239 lightning arrester?

The NEC defines "listed" as: Listed. Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned ...
Phil Frost - W8II's user avatar
6 votes
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Bonding ground rods for lighting protection

Consequence 1: it's not up to code. A contractor shouldn't do it that way, and if you do it yourself, it might make it difficult for you to sell your house (if you don't take everything down ...
hobbs - KC2G's user avatar
  • 12.4k
5 votes

Antenna, input and ground bonding

What size wire is recommended to bond the antenna ground to the electric service ground? I'd recommend (and electrical code may require) 6 AWG solid wire, both for electrical and mechanical reasons. ...
Phil Frost - W8II's user avatar
5 votes

How do I get my crystal radio to receive?

This design of a crystal radio relies on the capacitance of the antenna and the inter-winding capacitance of the inductor as well as the inductance of the inductor to form the tuned circuit. The ...
Glenn W9IQ's user avatar
  • 18.6k
5 votes
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Electrical Earth

Congratulations on getting permission to install an antenna. There are many hams that rent that would love to be in your position. As Phil correctly asks, why do you need an earth connection? Here ...
Glenn W9IQ's user avatar
  • 18.6k
5 votes

Wiring questions: grounding, attic antennas, BNC connectors

If you are in a jurisdiction that requires compliance with the US NEC (National Electric Code), you will probably find that there is no requirement for grounding the cable or having a lightning ...
Glenn W9IQ's user avatar
  • 18.6k
5 votes

What are the effects of a ground plane under a horizontal dipole?

If the container is small relative to wavelength, then it won't have much effect at all. If it's very large (say, infinite) then it will reduce ground losses by providing a more conductive ground ...
Phil Frost - W8II's user avatar
5 votes
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How do I interpret the FCC ground conductivity map files?

Here are the fields for AM_conductivity_m3.seq_.txt and AM_conductivity_m3hw.seq_.txt files: 4001 21.5750 158.2760 21.5840 158.1900 2.00 5000.00 Fields, ...
user3486184's user avatar
  • 1,902
5 votes
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Why are many ground radials preferable to a single ground stake buried 1m deep?

A dipole antenna does not require a connection to an "r-f ground" reference, either in the form of a ground rod or a set of buried radials. Its radiation efficiency typically is ~95% or ...
Richard Fry's user avatar
  • 2,922
5 votes

Connecting copper strap to grounding rod

There are some suitable connections in the reusable Cadweld product line: But you're right, there don't appear to be any similar connections in the One Shot line. An alternative is brazing. An alloy ...
Phil Frost - W8II's user avatar
5 votes

Grounding a vertical antenna from a balcony

Engineer999. While it might seem like a good idea to connect your antenna to the building ground wire, my experience has been that for those vertical antennas which are designed to operate without ...
Andrew's user avatar
  • 3,685
4 votes

Grounding a second-story shack with an outdoor antenna

Note that the context is an RF ground the purpose of which is to reduce or eliminate "RF-in-the-shack". If an antenna system is perfectly balanced, there is no need for an RF ground because there will ...
Cecil - W5DXP's user avatar
4 votes
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Grounding a dipole

The typical amateur radio / SWL budget will rarely allow for sufficient protection from a direct lightning strike. More often than not, the measures taken help minimize damage from a direct strike but ...
Glenn W9IQ's user avatar
  • 18.6k
4 votes
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guard planes in differential antenna PCB designs

The PCB shown here is a demo board, described in this TI application note. Point is that all the components in the schematic (p.4) that are not on top of this design are on the bottom side – and that ...
Marcus Müller's user avatar
4 votes
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Bonding of Coax shield to RF ground conductor for long ground runs?

Bond it all together. At both ends, if you can. Effective lighting protection isn't really just about providing a path to ground, though that's part of it. More importantly, lightning protection is ...
Phil Frost - W8II's user avatar
4 votes
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SDR - discone antenna setup

The symptoms described are consistent with common mode currents. These are undesired currents flowing on the outside of the shield of the coax (desired currents flow on the inside of the shield and ...
Glenn W9IQ's user avatar
  • 18.6k
4 votes

Antenna installation for a base station

Regarding the overlap of the mast to the antenna, there should be about 1 foot of overlap as shown in this picture: The top of the pipe must stay below the decoupling radials in order for the antenna ...
Glenn W9IQ's user avatar
  • 18.6k
4 votes

Is a J-pole an appropriate antenna for mounting to a steel handrail?

I have several years of experience operating in the high Alps in Switzerland as well as the lower range mountains in der Pfalzer Wald and der Schwartzwald (the Black Forest) in Germany on UHF, VHF, ...
Glenn W9IQ's user avatar
  • 18.6k
4 votes

What's the earth in this antenna exactly?

The ground/earth connection is for a length of wire that acts as a counterpoise. The instructions for the antenna (if there are any) may specify how long this wire needs to be (typically 1/4 ...
imabug's user avatar
  • 689
4 votes

Do I have to disconnect antennas during thunderstorms?

As far as I know the probability of direct strike to the antenna is considered relatively small. And if it will happen it is unlikely that your antenna will survive anyway (or the protection will cost ...
Aleksander Alekseev - R2AUK's user avatar
4 votes
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Grounding a chimney mounted antenna

You should definitely ground the antenna to your earth system with a heavy conductor. The coax alone will not cope well with the lightning current. By carrying a share of the current, the earth wire ...
tomnexus's user avatar
  • 11.2k

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