Observer's frame of reference in spacetime
Quantum field theory is the most precisely tested physical theory in history, and forms the Standard Model of particle physics. The quantum electrodynamics part has been tested to many decimals - not for masses or force strengths, but for correction factors to small magnetic coupling errors such as a 0.116 % increase in the real magnetic moment over the simple Dirac prediction for that value, and half lives for particles.
According to this theory, forces result from the exchange of radiation which is not otherwise detectable. You can't detect the vector boson radiation that causes force in any way other than by forces (because of inertia, which is a resistance of mass to accelerations).
A radio, for example, will not detect vector bosons from charges, unless of course the charges are accelerating with a frequency that the radio is tuned to detect. The radiation power in watts from a non-relativistic accelerated charge is simply P = (e^2)(a^2)/[6(Pi).(Permittivity)c^3] where e is electric charge, a is acceleration, and c is velocity of light. The radiation occurs perpendicular to the direction of the acceleration.
If the electrons have a velocity approaching that of light (in a straight line), the equation becomes more complex. For a logic step, the electrons at the front can undergo a large acceelration, so because in this situation each conductor (wire) is carrying an inverted image of the field and current in the other, they each radiate and exchange energy at the logic front. Furthermore, the exchange is perfect. There is no loss to the surroundings, because the radiated signals from each conductor cancel each other out perfectly beyond the transmission line. Hence the entire energy radiated due to the step in each conductor is radiated to the other conductor, so each causes the signal to propagate in the other. See the diagram and discussion here.
Technically, this is very sweet. Ivor Catt is supposed to be interested in this, but despite my having written several articles about his work, including his award winning computer development, he doesn't reply in a civilised way to these developments.
This is because he is fixed in a false simplified paradigm of Heaviside from 1893 and Catt has developed a whole philosophy of suppression since 1976 to defend it. He is stuck in his paradigm and cannot advance. Likewise, the string theorists are stuck in an unattractive conjectural framework which I've proved to be wrong by proving that the correct gravity is simply unified with electromagnetism by the vector boson exchange dynamics of electromagnetism:
Quantum field theory accounts for electrostatic (Coulomb) forces vaguely with a radiation-exchange mechanism. In the LeSage mechanism, the radiation causing Coulomb's law causes allforces by pushing. I worked out the mechanism by which electric forces operate in the April 2003 EW article; attraction occurs by mutual shielding as with gravity, but is stronger due to the sum of the charges in theuniverse. If you have a series of parallel capacitor plates with differentcharges, each separated by a vacuum dielectric, you need the total (net) voltage needs to take into account the orientation of the plates.
The vector sum is the same as a statistical random walk (drunkard's walk): the total is equal to the average voltage between a pair of plates, multiplied by the square root of the total number (this allows for theangular geometry dispersion, not distance, because the universe is spherically symmetrical around us - thank God for keeping the calculation very simple! - and there is as much dispersion outward in the random walk asthere is inward, so the effects of inverse square law dispersions and concentrations with distance both exactly cancel out).
Gravity is the force that comes from a straight-line sum, which is the only other option than the random walk. In a straight line, the sum of charges is zero along any vector across the universe, if that line contains an average equal number of positive and negative charges. However, it is equally likely that the straight radial line drawn at random across the universe contains an odd number of charges, in which case the average chargeis 2 units (2 units is equal to the difference between 1 negative charge and1 positive charge). Therefore the straight line sum has two options only, each with 50% probability: even number of charges and hence zero net result,and odd number of charges which gives 2 unit charges as the net sum. The mean for the two options is simply (0 + 2) /2 = 1 unit. Hence electromagnetism is the square root of the number of charges in the universe, times the weak option force (gravity).
Thus, electromagnetism and gravity are different ways that charges add up. Electric attraction is as stated, simply a mutual blocking of EM "vector boson" radiation by charges, like LeSage gravity. Electric repulsion is an exchange of radiation. The charges recoil apart because the underlying physics in an expanding universe (with "red-shifted" or at least reduced energy radiation pressing in from the outside, due to receding matter in the surrounding universe) means their exchange of radiation results in recoil away from one another (imagine two people firing guns at each other, for asimple analogy; they would recoil apart). Magnetic force is apparently, as Maxwell suggested, due to the spins of the vacuum particles, which line up.