Re: [amsat-bb] MUF and connecting to sattellites

[Joe Fitzgerald <jfitzgerald@xxxxxxxxxxxx>]

Jerry Weihrauch wrote:
> Does the MUF effect how well one gets their signal to a satellite like 
> PCSat2 on 29.400?
>

Jerry Weihrauch wrote:

 > Does the MUF effect how well one gets their signal to a satellite 
like PCSat2 on 29.400?


Only at very low elevation angles.  The MUF is usually specified for 
some particular distance across the earth's surface, e.g. 3000km, and 
one can calculate the angle  of incidence your signal will have with the 
ionosphere for a path of that length.  For angles greater than that, 
like when your signal is going to the spacecraft at some relatively high 
elevation, there is less of an effect.  For example as this is being 
written "foF2" the highest frequency that gets reflected from the F2 
layer in the Boston area for a signal going straight up (angle of 
incidence = 90 degrees) is 5.35 MHz (see digisonde.haystack.edu).  I 
might have a problem on an overhead pass if the spacecraft's receiver 
were on 80M.  I don't believe foF2 ever gets as high as 29 MHz.

That being said, if the MUF is above 29MHz, you may see attenuation of 
your uplink at low elevation angles.  At this point of the sunspot 
cycle, I don't expect you to see that very often.

-Joe KM1P
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