antenna stuff

Thread Starter


Joined Dec 9, 2006
A yagi has elements that are recievers. they are .25 of a cycle..?? Why are they not a full cycle length.?
Why are some Yags have smaller elements towards the end but others have elements
that are all the same size..??
Is a patch antenna a form of Yagi??
The little patch antenna that comes with Satellite radios is what kind??
They say to place it close to your FM antenna if you want to use the FM system for broadcasts. If the signal comes down as a modulated digital signal then where does the conversion take place. Does the signal go to the patch,then the conversion box, then back to
the patch and then jump to the FM antenna??? If the digital signal just jumped to the FM
antenna it wouldnt be intelligible..
Why is a dish shape reflector with a yagi in the middle so much better than a straight yagi??
I just read an aarticle that said if you are installing a dish antenna and you move it 1-2
inches the wrong way you wont get any satellite signal. If thats so how thw hell can so
many people in a city still zero in on the signal of one satellite?? Thanks:eek:


Joined Apr 20, 2004

About the satellite being available to many - we can all see the sun, too. It's further off than the geosynchronous satellite.

You might be interested in reading up on antenna theory.


Joined Jan 10, 2006
Think of the satellite as a light bulb out in space, and the dish is a magnifying glass trying to focus that light onto a tiny spot (the LNB)..... the co-ordinates have to be fairly precise, and you need a bloody steady hand.


Joined Nov 21, 2006
Hello aac9876
To answer all of your questions here could get quite lengthy, so, let me dig up some links for you that will give you basic answers. Let's deal with the facts dealing with yagi antennas first.
go here:

I'll try to find a link on parabolic reflector antennas (dish antennas) next and post it here soon.


Joined Dec 13, 2005
the reason they use 1/4 wavelength for the driven elements is the impedance is easy to match to the feedline impedance,the different ratios of element length and element spaceings change the focus of the signal, and the bandwidth of the antenna. The amount of gain depends on how much the beam is focused just like a search light.