Sunspot Activity & Radio Blackouts

Wed Jul 24 18:25:33 UTC 2002

--On Tuesday, July 23, 2002 10:11 PM -0700 Andy Ellifson 
<andy at ellifson.com> wrote:

> **** ( CORRECTED ) MAJOR SUNSPOT ACTITVITY ****

I passed this on to a neighbor for comment wrt 802.11b. His response 
appears below:

> These blackouts generally affect communications in the HF (high frequency)
> range. This means that frequencies below about 30-40Mhz will be affected.
> The reason is that the F layers of the ionosphere are used to "skip"
> signals for long distance communications. The solar storms cause massive
> disturbances in the ionosphere which cause this "skip" effect to shut
> down. It is actually impressive to listen to by virtue of the total
> absence of normal noise, or any other signal, on these bands of
> frequencies. These frequencies are used, on occasion, for extremely low
> speed commercial/military digital communications (110 baud).
>
> This should have no effect on us. The R3 classification will shut down HF
> radio communications for a bit, but the G2 geomagnetic classification is
> not too bad and should not affect the power grids. Severe geomagnetic
> storms can shift the magnetic poles by many degrees.
>
> There are many places to get more information about sunspots. Being an
> amateur radio operator who likes HF communications, I have a bit of an
> interest in the topic.
>
> The most succinct monitoring and information site I have found is run by a
> group of short wave listeners in the Netherlands:
> http://www.dxlc.com/solar/
>
> Many of the measurements used are taken in Boulder (Boulder K index). Nasa
> usually has some great photos of the big CMEs/Flares