Recent content by tech99

I think you were better off as you were. The signal strength at VHF falls off very rapidly with distance, and you cannot easily get enough antenna gain to make much difference. On the other hand, it is very easy to have an antenna which looks modern, but has problems, such as upward tilt or poor...

It appears to me that a standing wave may be defined as a wave where there is no net flow of energy. For there to be no net flow of energy the E and B fields must be in time quadrature. It is normal with a standing wave for the E and B field nodes to be located in different positions a quarter...

I can remember at school doing the double slit experiemnt using sodium light from a sodium salt placed in a Bunsen flame together with an additional slit. This arrangement gave sufficient spacial and temporal coherence. The resulting fringes were observed with a travelling microscope, or...

Maxwell noticed that the "cgs" units of permittivity and permeability were related by a number equal to the speed of light. So that the electric force between two charges would be related to the magnetic force between the two charges when moving by a factor equal to c. This seems to me to be...

It seems that they did know that charge flowed in a circuit. Thompson himself tries to measure charge by the time it takes to accumulate on a capacitor. When they experimented with electricity passing through gases, Thompson supposed that charge was being carried by corpusles, but it was not...

Not sure here but are you assuming that latitude is a great circle?

Is this definition universal, so it will hold if the wheel has a flange protruding below the contact surface, as on a train?

I suppose in a simple way that if we accelerate a charge using an alternating electric field, the radiated energy will, as always, be in quanta and the energy of each of these quanta will depend on the frequency of the alternating field.

If the signal and pump are both applied to the mass, then the deflections will add. But to produce parametric action the spring stiffness must chnage with deflection. This is what you are proposing, sounds correct. I think the pump needs to be large compared with the signal.

I suspect that providing cathodic protection to the interior of pipes is problematic, because the current will tend to flow locally, close to the zinc electrode. I am wondering if the discolouration of the copper you are seeing is dead algae and bacteria rather than a chemical action. It might...

I would be concerned about the toxicity of zinc.

I saw your question and do not know how to reply directly to you. The lever arrangement appears to give a step down in amplitude from the tympanum to the oval window. A step down in amplitude is accompanied by a step up in force, because energy is force x distance, so remains the same.

I think the underlying issue you have is that you need to undo the embedded test fixture parameters from your overall measured s-parameters. As s-parameters relate to power, not voltage, if the test fixture is not 50 Ohms then assumprtions about voltages will be incorrect.

You ask about pressure or force at the oval window. In a fluid we have pressure and in a system of levers we have force. In hydraulics, to create a given pressure in the fluid, a smaller piston travels further but requires less force. It seems to me that the mechanism is as follows. We start...

An inductor has a property of inertia, analogous to a mass. So when we try to alter the conditions, it will oppose the change. If we try to reduce the current in the inductor, it will create a forward voltage to try and keep the current flowing. You ask how an inductor can have a negative...