Channel Jumper wrote:

Public service radio - aircraft bands - are transmitted with massive
amounts of power.

No they are not. Most aircraft radios are around 10 watts and ground
stations around 25 watts.

Not to mention the fact that the airplanes are in the
air when they are mainly transmitting.

Pretty much correct.

Not that there is much traffic
to listen to anymore, with most things being computerized and digital.

Nope, aircraft communications is still AM voice and there is lots of it.

There is no reason to use a 3/4 wave antenna, nor is there any benefit
in using a antenna more then 5/8 wave long.

Might I suggest you get a copy of the ARRL antenna book, it will cover
it better then I can.

The bottom line is - if all you want to listen to is local traffic, all
you need is a 1/4 wave antenna - mounted outside, in as clear of a place
as possible.
Some building materials - concrete reinforced steel - being one, is
opaque to good radio reception.

All effective communications is line of sight.

Well, you got something right anyway.

The best scanner antenna for the money would be a Diamond Discone type
antenna - which would cover anything from 10 meters to 999 MHz - all in
one antenna.

Giant overkill just to listen to airplanes.

Using a good high grade coax and connectors would be key to good
reception.

Actually, if the goal is to hear ground stations, the key is antenna
height.

As a example, Cleveland Approach is 120 miles from my location, with my
Uniden 890XLT - I can hear Cleveland approach and the air traffic
between Cleveland / Pittsburgh and Baltimore MD from my location in
Central PA.

You do know that things like Approach are not usually on the airport.

Not to mention the local air traffic.

You normally hear lots of air traffic but not the ground station.

Even a old VHF television antenna would get you some reception...

Copper J Poles are great for experimental purposes, but not real good
when it comes to reliable reception - even though you are just going to
use it inside of your house.

There is nothing about a J pole that makes in unrealiable for reception
though it is again overkill for the application.

They do offer some front to back - directivity in one or more
directions, but there is no reason to use a piece of copper pipe if all
you want to do is receive.

There is no reason to use anything other than a piece of coax with the
center conductor stripped out for about 20 inches for receive.

You can acheive practically the same thing with a piece of 300 ohm twin
lead - if assembled properly.

I have even seen antenna's that were made out of copper foil that worked
for what you want to do.

For listening at home with my aviation HT, I use a piece of RG-58 that
has the shield pulled back about 20 inches with about 20 inches of center
conductor exposed. The end of the center conductor is soldered into a small
loop so I can hang the thing from the ceiling with a piece of string.