Propagation/Inductance.

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

> I may be wrong in my understanding of frequency and inductance, but I
> thought the two were interrelated?


	Assuming an LC tuned receiver, indeed.  However the
	effects have been extensisively studied, by the
	receiver (and trasmitter) designers and are well understood.

> If a radio station is broadcast at 300MHz and I'm receiving it at

> 305MHz, then I thought the inductance and capacitance of the signal

> would have to change in order for the frequency to change.


	One of several causes.  Things to think about:
		How is it known that the receptionis AT
		305?
		How accurate is the dial (?) calibration?
		Howmuch mechanical backlash in the tuner?
	Also, and subtle:
		Even if the Tx is on 300.00000000000000
		The Rx may be 'best' on 305.??? IF there
		is an adjacent signal.

	Also, the specific refernce was to 'tube type AM radios',
	imlpilictly Broadcast Band (tho i guess they need not
	be?  Unclear.)  If so, there are well known propagation
	effects AND the power change required of some stations.


> I dealt with this in greater detail in a previous post to you.  Direct
> heating can easily be proved to be inconsequential to the coil's inductance.
> If you live near Central Illinois, I can demonstrate to you a coil
> combination that has an inductance swing of from a few millihenries up to
> 25mH at any given moment.


	Measured with how many different instruments?
	(this is a routine question in any research....)

> This is no illusion.  Anybody out there who has a flat spiral coil and
solenoid coil can do this experiment.  It may be that
> my combination is more in tune since in this combination I use a solenoid
> with three times the wire length of the flat spiral.  Just connect the
> bottom wire of the solenoid to the center of the flat spiral and measure the
> difference between the two free wires.


	??
	Need to know a deal more about what is done to even guess.
	A 'sketch would help anyone understand.
	Does the observed change follow some _specific_ change?

	best
	dwp