zharca wrote:By concidence, I've just been trying to write up a description of antiskate/bias right now.
I have produced the following write up myself, maybe you are interested in the papers in order to squeeze some more info out of them:
Friction between stylus tip and the groove wall produces a force tangent to the groove. This frictional force depends on tracking force Fv and the friction coefficient my .
Ff = Fv x my
With 45 groove walls the load on each wall is 0.7 of the vertical or tracking force so that the friction force is 1.4 Fv x my .
my varies with record material and amount of groove modulation. Values were found to be between 0.22 and 0.64 for Shibata at 1.5 g tracking force .
The reaction force (to the friction force) of the tone arm passes through the arm pivot.
These two forces combine as vectors and, due to the offset angle (better : angle phi between groove tangent and effective length) of the cartridge, leave an unbalanced force, the skating force. This force tends to pull the arm towards the record's center.
The force is further determined by the magnitude of phi (or by the magnitude of offset angle and tracking error, respectively), tracking force, shape and condition of the diamond (new, worn), the cartridge’s mechanical resistance (cantilever damping) and record material.
Skating force, when uncompensated, produces distortions in the right channel (outer groove wall). Tracking force on the inner groove wall is increased, on the outer groove wall decreased . Uncompensated skating force results actually in the stylus mistracking the outer groove wall.
Uncompensated skating force results in increased record and tip wear at the inner groove wall (hence the left channel).
Skating force compensation enhances trackability by about 20-25 %. For obtaining equivalent trackability by increasing tracking force alone (without any compensation) an increase of 50 % would be required. This, however, would result in increased contact pressure and hence increased record wear.
The following findings presented by Kogen  are based on experiments and measurements.
Higher modulation velocities result in increased skating force [1, 2]. Wright  could show experimentally that the friction force increased for higher modulation velocities (for sinewaves). Snell and Rangabe  showed that the dependance of the friction force of modulation velocity was different for different cartridges (Decca, EMI, ADC, Goldring, Ortofon).
In 1968 RCA determined the effect of modulation velocity on stylus drag . It was found that for a tracking force of 1.5 grams the modulation velocity had little effect on measured groove speed as measured by means of a stroboscope. The same velocities had however a significant effect (factor 4) when a tracking force of 5 grams was applied. The measurements were performed on a lacquer test record. On a vinyl pressing the decrease in groove speed would be 0.7 of the one measured on the lacquer. The equipment used was not specified apart from weight and moment of inertia of the turntable.
According to Gilson  the effect of groove modulation (modulation drag) is composed of three related elements, inertial drag, compliance drag, transducer drag.
Inertial drag : energy absorbed in accelerating the stylus assembly (accelerations up to 1400 g have been observed). Since the deceleration force is lost in frictional loss and not fed back into the system, a constant torque is imposed on the turntable motor, such that the inertial drag is increasing towards the records centre.
Compliance drag : energy absorbed in overcoming stiffness and damping of the cantilever suspension. Greatest at low frequencies where lateral stylus excursion is at maximum. Compliance drag increases towards the record’s centre. Damping (and hence mechanical resistance) can vary considerably among different cartridges and even between samples of he same cartridge .
Transducer drag : energy absorbed in converting mechanical energy into electrical output from the generator system. It increases towards the record’s centre.
According to Gilson the tangential friction force further pulls the cantilever into line with the arm pivot. This cantilever displacement force is substantially the same as the frictional force Ff.
He concludes that by applying skating force compensation at the arm pivot bot the skating and the cantilever displacement force are compensated. Since on certain parts of the record there will be overcompensation and on the remaining parts undercompensation (see below), the cantilever will be displaced the record’s centre and towards the outer rim respectively. “The amount by which the cantilever/armature system is displaced will depend on the static compliance of the cartridge, and any ill-effects on sound quality will depend on the sensitivity of the transducer system to non-linearity due to displacement from the true dead-centre position.”
It has been found that elliptical styli produce greater skating force than spherical styli .
Groove velocity (for silent grooves) appears not to change skating force. . This finding was later confirmed by Wright  with an experimental setup (for measuring skating force) similar to the one used by Kogen , namely a cartridge that could swivel on a micro-bearing attached to the headshell. Wright used a Decca International tonearm because of the very low friction of its unipivot whereas Kogen used a Shure-SME 3009 tonearm.
Groove radius has an effect on skating force in that there is a minimum at
about 3.5 inch with maxima at outer an inner grooves, the value at the outer groove being higher
than at the inner groove , the curve being hence of parabolic shape. The skating force varies between 90 and 100 % of its maximum value.
These two preceding statements appear to be in contradiction but according to Kogen  there are factors not completely understood that result in the skating force differences that could be measured for various radii.
The skating force Fs is a function of R (groove radius), D (overhang) and L (effective arm length = linear distance arm pivot tip point) [2, 3].
Formula : Fs = Ff tan phi [2, 3, 4]
Ff = Frictional force = Fv x my
Sin Phi = (a + b) ; a = R/2L ; b=1/2RL x (2LD D*2)
phi (angle between groove tangent and effective length,) varies across the record surface with a minimum at about 3.5 inch and maxima at inner and outer grooves, the outer maximum being higher than the inner.
Skating force compensation is provided at the arm pivot. This means that a torque is applied at the pivot which results in a compensating force that is at right angles to the effective length. This compensation force is
determined by F = Ff sin phi which is different from the skating force Fs =
Ff tan phi (the tan phi vector is directed towards the record’s centre whereas the sin phi vector is at right angles to the effective length).
A different way of calculating skating force is to use offset angle theta and tracking error alpha . For groove radii greater than outer null and smaller than inner null, the skating force is
Fs = Ff x sin (theta + alpha)
Between the two null points, the skating force is
Fs = Ff x sin (theta - alpha)
You need a groove to produce that skating force, so you need also a groove to adjust anti skating. Try the Hifi News and Reviews test record. There is a track for anti skating adjustment (4 tracks at increasing signal levels). If you use another protractor or tone arm setup procedure than the one provided with the tone arm or recommended by XXX, respectively, the geometrical relations (offset angle) of arm cartridge record change. The skating compensation provided on the arm is designed for the arm being adjusted according to the manufacturer's specifications (or manufacturer's alignment tool).
 Alexandrovitch : A stereo groove problem, JAES, 1961, Jan., p.166
 Kogen : The skating force phenomenon, Audio, Oct.1967, p.53 ; Nov. 1967, p.38
 Bauer : Tracking angle in phonograph pickups, Electronics, March 1945, p.110
 Oakley : Skating force, mountain or molehill, Audio, March 1967, p.40
 Gilson : The cartridge alignment problem, Wireless World, Oct.1981, p.59
 Wright : Bias correction and dynamic conditions, Hi-Fi News, Oct.1969, p.1187
 Snell, Rangabe : Frictional drag and bias compensation, Hi-Fi News, Feb. 1970, p.221
 Randhawa : Pickup arm design techniques, Wireless World, March 1978, p.73 : April 1978, p.63
 Halter : Letters to the editor, JAES 1968, p.354
 Pardee : Determination of sliding friction between stylus and record groove, JAES 1981, p.890
Further papers :
Deane : Forward drag and stylus profile, Hi-Fi News, Oct.1969, p.1186
If you are interested, I can scan the papers (need an email address)..