Re: NOAA warning for rf communications

[Marshall Eubanks <tme () multicasttech com>]

At NASA at least, we referred to everything above 1 GHz as microwave. I 
have
never heard SHF and EHF used in practice (and I worked at 8 GHz and 
above for years).

There are two basic dangers here

- the electrical grid acts as a big radio antenna and circuit breakers 
may trip.

- The maximum frequency at which the ionosphere reflects radio waves 
(the MUF -
http://www.hfradio.org/muf_basics.html )
will increase. Some things that depend on ionospheric reflection may 
act weird, there
may be interference at higher frequencies which normally do not 
reflect, but now do, etc.

- it is also possible that dispersion (frequency depend phase changes) 
at higher
frequency could cut down on bandwidths of broadband systems.

The reflection frequency is almost never higher than 30 MHz anywhere on 
the planet, and the effects depend on the inverse frequency squared. I 
doubt that many of the bits moved by the readers of this list go at 
radio frequencies as low as 30 MHz. Even the cell phone and other bands 
starting about 700 Mhz are
unlikely to be affected.

Spacecraft may be effected, but this will be because they are bathed in 
increased radiation. There also may be some cool low latitude aurora.

On Friday, October 24, 2003, at 09:49 AM, Keptin Komrade Dr. BobWrench 
III esq. wrote:

> Well, this is more than you really wanted to know, but....
>
>         ELV     Exremely Low    dc - 3khz
>         VLF     Very Low Freq   3khz - 30khz
>         LF      Low Frequency   30khz - 300Khz
>         MF      Medium          300Khz - 3Mhz
>         HF      High            3mhz-30mhz
>         VHF     Very High       30mhz-300mhz
>         UHF     Ultra High      300-3Ghz
>         SHF     Super High      3Ghz - 30 Ghz
>         EHF     Extremely High  30Ghz - 300Ghz
>
> Different folks put the breaks at slightly different places (the.g. 
> the amatuer radio community puts the hf/vhf break @ 50Mhz and the 
> MF/HF break @ 1.8Khz.
>
> And, as a side note, I can't find the URL, but the US Cong is talking 
> about pulling all the funding for the NASA space weather programs. 
> Would mean less/no warning of this sort of stuff.
>
> We now return you to our regularly scheduled off topic discussions
>
> Komrade
>
> Owen DeLong wrote:
> > This will not likely affect point-to-point line-of-site 
> > communications above 50Mhz.
> > It will likely affect non-terrestrial communications and HF 
> > communications depending
> > on ionospheric reflection.
> > Owen
> > --On Friday, October 24, 2003 07:15:29 AM -0400 Todd Vierling 
> > <tv () duh org> wrote:
> > > On Thu, 23 Oct 2003, Roy wrote:
> > >
> > > : "Satellite and other spacecraft operations, power systems, high
> > > : frequency communications, and navigation systems may experience
> > > : disruptions over this two-week period."
> > > :
> > > : I think you will find that 802.11b and other terrestrial microwave 
> > > LOS
> > > : links don't meet any of those criteria and should be unaffected.
> > >
> > > "High frequency communications"?
> > >
> > > We *are* talking about multi-GHz frequencies here.
> > >
> > > --
> > > -- Todd Vierling <tv () duh org> <tv () pobox com>
                                 Regards
                                 Marshall Eubanks

T.M. Eubanks
e-mail : marshall.eubanks () telesuite com
http://www.telesuite.com