Do antennas need a ground or are they just connected to a signal output

 

Do antennas need a ground or are they just connected to a signal output

Antennas do not require a direct connection to a voltage reference point that we call ground. They do interact with ground planes and the terrestrial earth. Their height above the terrain can have a significant effect on the propagation of a transmitted signal or the ability to receive incoming signals.

 

Depends on the design, some use a ground plane counterpoise. Either artificial or actual. Most are not grounded. Coax antenna feeds have a grounded shield. Lightning suppression has an air gap to ground. etc. You can find ARRL antenna books in PDF on the net for free.

 

Hello,

What kind of antenna are you talking about?

Read the following books:
https://archive.org/details/fea_ARRL_Basic_Antennas
https://archive.org/details/TheArrlAntennaBook
It might give you a good insight of the antennas.

Bertus

 

If you are in the United States and apropos what kind of antenna, are you aware of WWVB? (https://en.wikipedia.org/wiki/WWVB ).

It transmits at only 60 kHz. There are antenna designs for it. I mention it, because it has been on the chopping block for funding for quite awhile, and it's sort of like listening to a piece of history while it lasts.

 

Ground rods alone are usually no ground at all at RF, but they are very handy for safety and bleed off wind-generated static charge nicely. They may help moderate damage in case of a lightning strike, if you are lucky. A lightning strike can easily carry 30,000 amps of RF current at about 2.4 Mhz. That is a bit more load than most antennas are designed for.

 

Do antennas need a ground or are they just connected to a signal output

Depends entirely on the antenna type design. Some they do and some they don't. Like others I suggest you read up on antenna designs.

Ron

 

Hello,

There are many ham radio books on antennas made.
Box73 has 38 english books available in their shop:
https://www.box73.de/index.php?cPath=33_35_49

Bertus

 

Antenna may be symmetric (like closed or open type dipoles or or Loop-frame constructions) demanding no any gnd. Antennas may be assymetric like Ground Plane or J-pole having no need for any gndp; or may be having hidden gnd like lambda/4 stick used in most of walkie talkies - then gnd stays in the user body via capacitance of hands to the PCB surface. And may be the case where clear gnd is must to be like hanging horizontal wire used in WW2 epoch systems.

The bigest problem yet is not the gnd but how to avoid the RF coming via coaxial braid. For me seems the best is coiling some turns of coaxial on the air-core keeper, however many constructors says they like more the ferrite core pushed over the cable. Then how they solve a problem of GHz range ferrite capable for kW of loss I dont know. This problem may be avoided if smart use the gnd, but it always are a headache.

 

And more: both Bertus reccomended books MUST be read from cover to cover, however I found no any button with what to make them readable (somehow 0,1 mm small letters I cannot read). And what is most woeful, I found no any button to save it let I use my own reader instead.
Bertus: may I kindly ask explain how to download it?

 

Hello,

On the right bottom of the internet archive page are the formats you can get them.
Here are the links for the PDF's:
https://archive.org/download/fea_ARRL_Basic_Antennas/ARRL_Basic_Antennas.pdf
https://archive.org/download/TheArrlAntennaBook/Hall-TheArrlAntennaBook.pdf
And here the DJVU, wich is much smaller to download:
https://archive.org/download/fea_ARRL_Basic_Antennas/ARRL_Basic_Antennas.djvu
https://archive.org/download/TheArrlAntennaBook/Hall-TheArrlAntennaBook.djvu

Here is a link to the DJVU reader:
https://www.djvureader.org/

Bertus

 

Thank You Bertus for good two new books in my library.
By the way, the djvu reader is not obligatory to read djvu books, there works rather acceptable the thing without of what the any PC is worthless semiconductor cemetery, namely IrfanView. However when the book is damn big like 2000 pages it becomes very slowish in contrast with djvuView, but anyway nothing must not be installed and for normal volume books it works well.
Hope You are acknown with Irfan - the only soft able to print pictures (eg PCB) in any size, make all the framing and delelte/paste style operations of picture fragment, revert sides, rotate, mirror, interchange colours (what is so important for PCB if to use a negative or positive photolitography), or alter the resolution by several algoritms (!!), and even create the slideshow for vodka party deccoration.

PS Probably my wrong rendering of the website came because long ago I needed to upgrade my Linux but then I will loss all my passwords what never I know in the head. So I suffer better instead with inability to render a newest generation www scripts. Need to find time to read how to export those passwords for saving.

 

Hello,

I do not have ifran on my PC as it is a linux system.
The PDF and DJVU files can be read in Okular on my linux system.
https://okular.kde.org/

For simple drawings I use Kolourpaint on my linix PC.
http://www.kolourpaint.org/
I also have GIMP for image processing on my linux PC.
https://www.gimp.org/

Bertus

 

I am on Linux as well, but Irfan works fine via Wine. Just let him to drink a bit of Wine and he will not notice any difference between Win soft and own soft

Yet GIMP I see as very powerful and clumsy/inhandly nightmare when it isnt possible to go around. Zillion times more easy and all the same functionally except the semi-transparent layers are Arcsoft Photo Studio (the same via Wine).

Weaker is about boozing the Sprint Layout. If I use my PCB_Layout or anything else, I shall not be able to interchange by PCB files with my workmates having the Windows. So I use Sprint but as it is heavy Wine-proof, I use the Virtual Box with Windows (shame on me, my only pardon is that copy isnt much legal so I havent supported the gangsters), thus the Sprint resides in the Virtual machine on the USB stick.

 

Hello,

We are drifting from the original subject now.
Do you know PortableApps ?
https://portableapps.com/
All runs from the USB stick.

Bertus

 

Yepp