I've got a CushCraft D40 rotatable dipole mounted on my tower's mast. At present, the tower is laying over horizontally. The D40 is about 6' off the ground. It is resonant at about 7035 with about 22
I would expect it to go up in frequency. David Robbins K1TTT e-mail: mailto:k1ttt@arrl.net web: http://www.k1ttt.net AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net _____________________________
Is it fair to generalize that proximate objects will almost always detune an antenna to a higher frequency? Or are there standard rules of thumb which help to ID when that is expected or not? doc --
No... imagine putting a giant sheet of metal near a dipole. It will tend to reduce the resonant frequency because it increases the apparent capacitance. Or, for the example originally given (a dipole
Doug: The resonant freq should INCREASE, but by how much is anyone's guess. However, I, too, have a D40 and found that its resonant freq and BW were exactly according to specs in the assembly manual.
Sorry, was distracted by a 3yr old ... not to say that my attention span is any better at times! I should have asked if proximity to solid objects typically lowers the frequency of resonance and inc