[Fwd: LF: Re: LF Propagation thoughts (and antenna, too)]
Sun, 06 Feb 2000 19:50:17 -0500
"M. Bruno" wrote:
> In 21.36 06/02/00 , Vaino OH2LX wrote:
> >Some thoughts on 136 kHz Ionospheric propagation
> >Sorry for this not being in phase with T/A ideas.
> >On the practicability of talking about "hops"
> >Suggested experiment: Draw a circle with a radius
> >of 63.70 cm. Then draw a slightly bigger circle
> >with radius of 64.50 cm, using same center point.
> >With a reflection height of some 80 to 90 km the
> >space between the concentric circles is small..?
> >Pictures are 99% drawn to a completely wrong scale.
> >Might be better talk abt "bends" instead of "hops".
> >Not all active hams are interested on this kind
> >of digging into propagation details. For those who
> >are, I'll be glad to calculate selected paths etc.
> Dear Vaino,
> please, continue your 'digging'. If our main objective
> in this fantastic hobby is self-instruction, we must
> have somebody teaching and helping us to remain with
> feet on Earth, even looking at the ionosphere ... ;-)
> May be true that not all active hams are interested; but I
> firmly believe that the main scope of this reflector is to
> put hams with similar interests in touch, and many of us
> must be concerned about wave propagation, to make
> better QSO or simply to try to understand.
> Your suggested experiment is very clear. In effect we are
> used to figure the ionospheric layers as an high ceiling;
> compared with the earth radius it is very low.
> I have a question for antenna modelling gurus (G3LDO?)
> What is the vertical radiation pattern of our shortened
> verticals? Is it dependent of ground resistance and nearby
> objects? may we model it?
> Marco Bruno - IK1ODO
> SPIN Electronics - www.spin-it.com