long wire antenna

In a very broad sense, the customer is correct. A 10m wire forms a 20m half-wave antenna, pretty much regardless of how it's oriented or it snakes around.

There are books on compact and hidden antennas you might want to look at.

It's not unlike a wing. Almost any surface flat on the bottom and curved on the top can produce lift.

What is the railing on the deck, wood or metal? He needs to keep the wire aeay from any metal.

Lenny-

This is a case of "try it and it will probably work".

I once lived in an apartment with a balcony that had a railing. Someone before me had bolted a CB 3/8-24 mirror antenna mount to the rail. I attached a 40 Meter mobile whip and used it as a transmit antenna. The Kenwood TS-690SAT had no trouble matching it. It didn't get out very well but reception was good.

For a general purpose shortwave antenna, a 102 inch CB Whip mounted this way on the railing, might work quite well. It could stick out away from the building. He could feed it with Co-Ax cable, or just another long wire between the whip and the radio's antenna terminal.

Fred

"klem kedidelhopper"

** For AM broadcast, by far the best is to use a frame aerial.

Heaps of stuff on the net about making them.

** Chances are any SW reception will be very badly affected by RFI from the thousands of nearby TVs, PCs and other assorted electronic devices using SMPSs that all radiate interference in the SW band. Only the strongest signals will be heard OK and them he can pick up on a whip antenna mounted on a balcony railing.

.... Phil

Or use the railing as antenna.

Also, when sort on space, a loop antenna might be usefull.

So how come a symmetrical wing, such as might be found on a stunt plane, still flies, and most asymmetric wings fly quite happily upside down ? :-)

Arfa

"Arfa Daily"

** I ask people who *think* they know how a plane flys that same Q.

Stumps them all the time.

Goes to show how simple explanations are often highly flawed.

..... Phil

I don't know. But that wasn't the point I was making.

With just a randomly oriented long wire you will get unpredictable results.

A better idea would be to get a PVC form of three to six inches and helically wind the wire. The exact length won't matter because you do not have a specific frequency in mind. Generally the more wire the better. Mount it vertically or if you like move it around for the best reception.

I saw an interesting dissertation on this some time back, which put forward a much more complex but better believable theory as to how a wing flies. I don't really remember the details, but it relied heavily on the wing's angle of attack into the air, to produce the pressure differential, and hence lift. I seem to recall that it was the opposite way round from the 'conventional' teaching of increased speed of the air over the top of the wing reducing the pressure, and that this theory had the attack angle causing compression under the wing, thereby increasing the pressure to produce lift. I do, however, remember it saying that air has no 'intelligence', and just because two previously adjacent molecules became divided above and below the wing, there was nothing to say that they had to form back up in the same way as they left the back edge of the wing, which would require the air to move faster over the longer upper surface. I believe it did say that the air actually does travel faster over the curved face of the wing, and that the fact that it does, does produce a reduction in pressure. However, this reduction is small, and only contributes a very limited amount of lift, compared to the main mechanism that's at work.

Arfa

forward

angle

to

curved

I see your reasoning, but I don't think it's right. If the air near the surface of the wing did not travel faster over the top of the wing, there would be a buildup of air at the front.

And let's not forget that little experiment where one blows over the top of a strip of paper, demonstrating, Bernouilli's Law.

Of course, this isn't to say that there is /only one way/ for a wing to produce lift. But I don't want to get involved in this. Again, the point I was making has been completely missed. What else is new?

It's not really that complex. Didn't you ever, as a kid, hold your arm out the car window with your hand flat and "fly" it up and down as you changed the angle of attack? That's really all that's necessary. An airplane could fly (if not very efficiently) with wings made from flat sheets of plywood.

--
Rich Webb     Norfolk, VA

All you've got there is an inclined plane. You aren't creating lift.

Try it without the car.

The saying goes something like: with enough power, you could fly a brick. The lift comes from the angle of attack.

--
Rich Webb     Norfolk, VA

Nope. You're just describing a fin.

Lift comes from turbulance on the upper edge causing a vacuum. Without the airfoil, what you have is pre wright brothers technology which didn't fly.

The Wright's were pretty smart and used a good airfoil design, otherwise they'd have had to wait for another generation of efficient (power vs weight) internal combustion engines to make the first flight. Good designs have less drag and do produce more lift. Poor designs need more thrust.

Ever fly one of those balsa wood gliders? (Do they even still make those?) Body & rudder, wings, and elevators all punched out of a flat sheet. Stick on a prop and a rubber band engine and it does fly.

Rack time ...

--
Rich Webb     Norfolk, VA

Tell that to a Harrier pilot.

Horsepower is king.

"AZ Nomad"

** Bollocks.

Study this page very carefully:

.... Phil

Lift is still lift, whether it comes from the shape of the device or the angle of attack. When you change the angle you increase the pressure on the bottom. With a difference in pressure you have lift. As has been said before, not very efficient, and not straight up, and therefore difficult to create controlled flight.

Leonard