Do you know what 4 to 6 db loss in power is? 3db is half power and another 3db is half again = 1/4 power in reference to a full length Antenna whip. You don't have the range when you coil up an Antenna. That's called loading the Antenna.
What was also meant on the Antenna pointing at the receiver. Is that the coil on the end of the rubber ducky in effect is horizontal by a small degree and therefore radiates better than a whip. It is a much better antenna if you-have-to point your antenna at a receiver.Whip Antenna have very little surface on the tip. Also, what they don't talk about is the receive Antenna and how it too is directional. It won't receive worth beans off the end of the wire as the test shows. If you let it dangle out the end, it will receive allot better. Think about launching a Sailplane off a wench and have your TX antenna still collapsed. You can launch just fine, till you do the zommie. If you find out in time and pull out the Antenna you may just save it. I like to have the best performance from my Tx and Rx all the time. Any time you degrade from that setup. You reduce your margin of safety to keep it flying.
The worst setup is putting the receiver wire Antenna inside a carbon tube or inside a Fuse covered with Chrome Monocoat. When you shield a Receive Ant in a conductive material, that will reduce the receive signal. If you point a Antenna or reduce its radiated signal by making it smaller, that reduces the receive signal.
The best setup is having a receiver Antenna exposed and dangling some. Using a dual conversion receiver. Good batteries at full charge. TX that has the full Ant whip angled up out of the Tx case. Most people like to look straight at their Sailplane while flying. That normally makes the Antenna point at the Sailplane. So if you can angle the Ant up or even down or turn sideways. A little more RF will be going in the direction needed.
If you just have to have a smaller Ant. Get one that flops over some. That will give you more signal than a rubber ducky that is stiff and ridged. The more your Sailplane can see of the Tx Ant, the better it likes it.
Larry Taylor KF6JBG CD for the Visalia Fall Soaring Festival 2005 Oct 1st & 2nd Home: [EMAIL PROTECTED]
----- Original Message ----- From: <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Thursday, March 24, 2005 4:54 AM
Subject: Re: [RCSE] 51 MHz base loaded antenna for 9303
Larry Taylor wrote:
The Small Ant will not radiate off the end...
Indeed it will. I'm not making this up. Read what Peter Berg, designer of Berg receivers, has to say about the tests he performed:
http://www.bergent.net/antenna_field_test.html
"CONCLUSION: Pointing a whip antenna at the plane is BAD, and pointing a rubber duck antenna at the plane is GOOD. These measurements proved nothing new. We have known for a long time that the antenna patterns are as described..."
Mike
--
Winch Solenoid Safety Buzzer - http://www.vvsss.com/buzzer/
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