One can project a circle of given diameter in miles or KM on a Google Earth
map. I've done it but can't remember how. Maybe you need to generate a
.KMZ file and import it ? ?
Keith J Morehouse
Managing Partner
Calmesa Partners G.P.
Olathe, CO
On Mon, Oct 24, 2016 at 2:13 PM, Paul Rollinson <Paulrollinson@sbcglobal.net
> wrote:
> This has me very intrigued.
>
> Do you know of any software that could project an arc 800-1000KM from my
> QTH? That way, I can look for a station that would theoretically, be in the
> target area to experiment with.
>
> Thanks,
>
> Paul Rollinson, KE1LI
> Rollinson Associates
> 860-928-5147
> 860-928-3844 Fax
> 860-208-8814 Cell/Text
> Paulrollinson@sbcglobal.net
>
> Representing Component Part
> Manufacturers for over 35 years
>
>
> -----Original Message-----
> From: VHFcontesting [mailto:vhfcontesting-bounces@contesting.com] On
> Behalf
> Of Keith Morehouse
> Sent: Monday, October 24, 2016 3:38 PM
> To: vhfcontesting@contesting.com
> Subject: Re: [VHFcontesting] Ionosphere Scatter
>
> There is a considerable amount of path loss, so, in theory, all the "good
> things" you would want for long-haul troposcatter (or sporadic-E) are
> useful for ionoscatter. High ERP, low angle take-off and low environmental
> noise. Research says scattering occurs around 80-90 KM up, so more-or-less
> the same ionospheric height as some sporadic-E. Because there is
> refraction
> in the ionosphere, there will be a minimum distance for Ionoscatter of
> approx 800-1000 KM ("skip zone"), with a maximum distance based on your
> ability to get a signal into that 80-90 KM high sweet spot (just like Es).
> Distances shorter then 800-1000 KM can be covered (somewhat unreliably)
> with
> troposcatter. Studies show there is a diurnal
> (daily) variation in ionoscatter signal strength of around 10 dB, with
> minimum attenuation (maximum signal strength) occurring at mid-path noon.
>
> Note that path attenuation increases rapidly as frequency increases. The
> optimum traffic frequency (FOT) for ionoscatter was calculated many years
> ago as 50-60 MHz, taking into account path loss vs typical band noise
> levels. At low and mid-band frequencies, path loss increases about 5 dB
> for
> every 10 MHz upward change of frequency. This is why ionoscatter at
> 144 MHz is much more difficult.
>
> Jay W9RM
> DM58 CO
>
> Keith J Morehouse
> Managing Partner
> Calmesa Partners G.P.
> Olathe, CO
>
> On Mon, Oct 24, 2016 at 11:32 AM, Mark Spencer <mark@alignedsolutions.com>
> wrote:
>
> > Hi this is interesting. From a practical perspective I'd be curious in
> > knowing if there is much difference in what needed to be successful
> > using long haul tropo scatter versus iono scatter on 50 MHz ?
> >
> > Presumably bigger antennas, higher power levels and a clear view of
> > the horizon will all be useful ?
> >
> > The comments about the K index and time of day for iono scatter are of
> > particular interest to me.
> >
> > 73
> > Mark S
> > VE7AFZ
> >
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