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OT: K-index=2, But Bands Deader Than Doornail?

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Jeff-229

OT: K-index=2, But Bands Deader Than Doornail?

My apologies for going off-topic, but I'm learning to interpret the various
solar parameters, such as the A- and K-indexes, and I'm a bit confused. The
K-index is only 2 at 2045 UTC on Dec. 19, but I can't hear ANY CW signals on
any band, which, until recent weeks, was a very unusual state of affairs.
The A-index is 9, which I believe is also relatively low. Shouldn't I be
hearing at least a couple of signals, or is it just that everyone is still
at work?

Thanks & Happy Holidays,
Jeff
WB5GWB
Long Island, NY

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Stephen W. Kercel

Re: OT: K-index=2, But Bands Deader Than Doornail?

Jeff:

It is a perfectly reasonable topic, and one I've been wondering about myself.

Since Thanksgiving, we've had astoundingly bad conditions with lots
of flares and storms.

There are three mechanisms of disruption indicated on the NOAA Web
site, radio blackouts due to X-rays which are mostly felt on the
sunlit side of the Earth and dissipate in a matter of hours, "solar
storms" which are bursts of heavy particles (protons, as I recall),
and the solar wind (a stream of electrons).

As I understand the numbers, K is a "near real time" (reported every
3 hours) indication of disruption of propagation due to the
geomagnetic fluctuations caused by fluctuations in the solar wind.
With each value of K there is an associated value of a, with a pseudo
logarithmic relationship between K and a, such that k=1 => a=3, and
k=9 => a=400. A is the average of the last 8 a values, and thus is an
indication of the cumulative effect of the solar wind on the
geomagnetic field over the past 24 hours.

It is important to realize that A and K are statistical measures that
correctly describe propagation most of the time, but not always.

A=9 is not low. It is usually an indication of "marginal but somewhat
useful" conditions.

My guess is that when the atmosphere takes a series of severe hits,
as has happened over the past week, it takes much more than 24 hours
(suggested by formula for the A index) for the atmosphere to "heal"
itself, irrespective of the low A and K values currently being reported.

It is my observation over recent months that once we've had a
geomagnetic storm it requires two continuous days of both K and A <=
2 before one sees the return of good conditions.

The problem is aggravated by the low sunspot numbers, and consequent
low MUFs. I've noticed that most nights lately from New England, one
hears practically nothing from Europe on 40 m (although one can hear
Caribbean stations running European pileups). The reason is that the
MUF between NE and EU most nights is about 6 MHz. 40 is dead but 80
(in between storms) can be very lively.

Anyway, given the low MUFs, most HF bands are dead much of the time,
and 80 is only usable when the noise (partly induced by geomagnetic
activity) dies down.

I'd be curious what other list members know about this.

73,

Steve Kercel
AA4AK

At 03:53 PM 12/19/2006, Jeff wrote:

>My apologies for going off-topic, but I'm learning to interpret the various
>solar parameters, such as the A- and K-indexes, and I'm a bit confused. The
>K-index is only 2 at 2045 UTC on Dec. 19, but I can't hear ANY CW signals on
>any band, which, until recent weeks, was a very unusual state of affairs.
>The A-index is 9, which I believe is also relatively low. Shouldn't I be
>hearing at least a couple of signals, or is it just that everyone is still
>at work?
>
>Thanks & Happy Holidays,
>Jeff
>WB5GWB
>Long Island, NY
>
>_______________________________________________
>Elecraft mailing list
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>
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Jay Schwisow

Re: OT: K-index=2, But Bands Deader Than Doornail?/Try beacons

Stephen/Jeff,

Always take a listen to the HF beacons. This is a great way to see if
the bands are "open". Right now from Colorado, I can hear W6 and KH6
on both 15 and 20 meters.

http://www.ncdxf.org/Beacon/BeaconSchedule.html

73,

Jay - KT5E

Stephen W. Kercel wrote:

> Jeff:
>
> It is a perfectly reasonable topic, and one I've been wondering about
> myself.
>
> Since Thanksgiving, we've had astoundingly bad conditions with lots of
> flares and storms.
>
> There are three mechanisms of disruption indicated on the NOAA Web
> site, radio blackouts due to X-rays which are mostly felt on the
> sunlit side of the Earth and dissipate in a matter of hours, "solar
> storms" which are bursts of heavy particles (protons, as I recall),
> and the solar wind (a stream of electrons).
>
> As I understand the numbers, K is a "near real time" (reported every 3
> hours) indication of disruption of propagation due to the geomagnetic
> fluctuations caused by fluctuations in the solar wind. With each value
> of K there is an associated value of a, with a pseudo logarithmic
> relationship between K and a, such that k=1 => a=3, and k=9 => a=400.
> A is the average of the last 8 a values, and thus is an indication of
> the cumulative effect of the solar wind on the geomagnetic field over
> the past 24 hours.
>
> It is important to realize that A and K are statistical measures that
> correctly describe propagation most of the time, but not always.
>
> A=9 is not low. It is usually an indication of "marginal but somewhat
> useful" conditions.
>
> My guess is that when the atmosphere takes a series of severe hits, as
> has happened over the past week, it takes much more than 24 hours
> (suggested by formula for the A index) for the atmosphere to "heal"
> itself, irrespective of the low A and K values currently being reported.
>
> It is my observation over recent months that once we've had a
> geomagnetic storm it requires two continuous days of both K and A <= 2
> before one sees the return of good conditions.
>
> The problem is aggravated by the low sunspot numbers, and consequent
> low MUFs. I've noticed that most nights lately from New England, one
> hears practically nothing from Europe on 40 m (although one can hear
> Caribbean stations running European pileups). The reason is that the
> MUF between NE and EU most nights is about 6 MHz. 40 is dead but 80
> (in between storms) can be very lively.
>
> Anyway, given the low MUFs, most HF bands are dead much of the time,
> and 80 is only usable when the noise (partly induced by geomagnetic
> activity) dies down.
>
> I'd be curious what other list members know about this.
>
> 73,
>
> Steve Kercel
> AA4AK
>
>
>
> At 03:53 PM 12/19/2006, Jeff wrote:
>> My apologies for going off-topic, but I'm learning to interpret the
>> various
>> solar parameters, such as the A- and K-indexes, and I'm a bit
>> confused. The
>> K-index is only 2 at 2045 UTC on Dec. 19, but I can't hear ANY CW
>> signals on
>> any band, which, until recent weeks, was a very unusual state of
>> affairs.
>> The A-index is 9, which I believe is also relatively low. Shouldn't
>> I be
>> hearing at least a couple of signals, or is it just that everyone is
>> still
>> at work?
>>
>> Thanks & Happy Holidays,
>> Jeff
>> WB5GWB
>> Long Island, NY
>>
>> _______________________________________________
>> Elecraft mailing list
>> Post to: [hidden email]
>> You must be a subscriber to post to the list.
>> Subscriber Info (Addr. Change, sub, unsub etc.):
>> http://mailman.qth.net/mailman/listinfo/elecraft
>>
>> Help: http://mailman.qth.net/subscribers.htm
>> Elecraft web page: http://www.elecraft.com
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>

Bill VanAlstyne W5WVO

Re: OT: K-index=2, But Bands Deader Than Doornail?

In reply to this post by Stephen W. Kercel

Steve,

Terrific summary, thanks for contributing that.

It is also interesting to note that, since this period of unstable space
weather started, there has been little to no sporadic-E propagation on 6M --
this during a seasonal period when one would expect (based on past history)
fairly regular openings.

I've read in a number of places over the years that mid-latitude sporadic-E
propagation does seem to be inhibited by large-scale geomagnetic
disturbance, just as HF propagation is -- albeit perhaps by a different
mechanism. If the mechanism is indeed different (and it seems to me it would
almost have to be), I'm not aware of any theory on how it might work. I have
a few home-grown hypotheses on the matter, but nothing I'm willing to admit
to in public. :-) Anyone know of any science on the relationship between
mid-latitude sporadic-E propagation and geomagnetic disturbance?

Bill / W5WVO

Stephen W. Kercel wrote:

> Jeff:
>
> It is a perfectly reasonable topic, and one I've been wondering about
> myself.
> Since Thanksgiving, we've had astoundingly bad conditions with lots
> of flares and storms.
>
> There are three mechanisms of disruption indicated on the NOAA Web
> site, radio blackouts due to X-rays which are mostly felt on the
> sunlit side of the Earth and dissipate in a matter of hours, "solar
> storms" which are bursts of heavy particles (protons, as I recall),
> and the solar wind (a stream of electrons).
>
> As I understand the numbers, K is a "near real time" (reported every
> 3 hours) indication of disruption of propagation due to the
> geomagnetic fluctuations caused by fluctuations in the solar wind.
> With each value of K there is an associated value of a, with a pseudo
> logarithmic relationship between K and a, such that k=1 => a=3, and
> k=9 => a=400. A is the average of the last 8 a values, and thus is an
> indication of the cumulative effect of the solar wind on the
> geomagnetic field over the past 24 hours.
>
> It is important to realize that A and K are statistical measures that
> correctly describe propagation most of the time, but not always.
>
> A=9 is not low. It is usually an indication of "marginal but somewhat
> useful" conditions.
>
> My guess is that when the atmosphere takes a series of severe hits,
> as has happened over the past week, it takes much more than 24 hours
> (suggested by formula for the A index) for the atmosphere to "heal"
> itself, irrespective of the low A and K values currently being
> reported.
> It is my observation over recent months that once we've had a
> geomagnetic storm it requires two continuous days of both K and A <=
> 2 before one sees the return of good conditions.
>
> The problem is aggravated by the low sunspot numbers, and consequent
> low MUFs. I've noticed that most nights lately from New England, one
> hears practically nothing from Europe on 40 m (although one can hear
> Caribbean stations running European pileups). The reason is that the
> MUF between NE and EU most nights is about 6 MHz. 40 is dead but 80
> (in between storms) can be very lively.
>
> Anyway, given the low MUFs, most HF bands are dead much of the time,
> and 80 is only usable when the noise (partly induced by geomagnetic
> activity) dies down.
>
> I'd be curious what other list members know about this.
>
> 73,
>
> Steve Kercel
> AA4AK
>
>
>
> At 03:53 PM 12/19/2006, Jeff wrote:
>> My apologies for going off-topic, but I'm learning to interpret the
>> various solar parameters, such as the A- and K-indexes, and I'm a
>> bit confused. The K-index is only 2 at 2045 UTC on Dec. 19, but I
>> can't hear ANY CW signals on any band, which, until recent weeks,
>> was a very unusual state of affairs. The A-index is 9, which I
>> believe is also relatively low. Shouldn't I be hearing at least a
>> couple of signals, or is it just that everyone is still at work?
>>
>> Thanks & Happy Holidays,
>> Jeff
>> WB5GWB
>> Long Island, NY
>>
>> _______________________________________________
>> Elecraft mailing list
>> Post to: [hidden email]
>> You must be a subscriber to post to the list.
>> Subscriber Info (Addr. Change, sub, unsub etc.):
>> http://mailman.qth.net/mailman/listinfo/elecraft
>>
>> Help: http://mailman.qth.net/subscribers.htm
>> Elecraft web page: http://www.elecraft.com
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

Geoffrey Mackenzie-Kennedy-2

Re: OT: K-index=2, But Bands Deader Than Doornail?

Bill W5WVO [hidden email] wrote:

> I've read in a number of places over the years that mid-latitude
> sporadic-E propagation does seem to be inhibited by large-scale
> geomagnetic disturbance, just as HF propagation is -- albeit perhaps by a
> different mechanism. If the mechanism is indeed different (and it seems to
> me it would almost have to be), I'm not aware of any theory on how it
> might work. I have a few home-grown hypotheses on the matter, but nothing
> I'm willing to admit to in public. :-) Anyone know of any science on the
> relationship between mid-latitude sporadic-E propagation and geomagnetic
> disturbance?

---------------------------------------------------------------------------

Bill,

Although not published science (as far as I am aware) sufficient evidence
has been collected during the past 40 - 50 years to suggest that geomagnetic
disturbances do have an effect on the usual type of mid-latitude E layer hop
type propagation. At VHF a geomagnetic disturbance appears to have the
greatest effect on paths which follow lines of equal geomagnetic latitude,
apparently creating ducts which provide the means for contacts over very
long distances i.e around 2000 miles plus, without any closer signals being
heard. Auroral Es is probably one example of such propagation, which also
works at 70 MHz as some of us found out in 1970 while attempting a 4m/6m
contact across the pond when I was a VE2. The effect on paths which cross
lines of geomagnetic latitude e.g. VE2 to South America are more difficult
to assess using ham signals because of the level of activity, but
occasionally S.American comms just below 50 MHz would appear for a short
period during or after a disturbance without any sign of the 6m US ham
signals usually heard during an Es opening.

Something similar happens here on 40m with Far Eastern stations (short path)
suddenly appearing after the Europeans suddenly disappear, but this is a
rare situation.

73,
Geoff
GM4ESD

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Jim Campbell-8

Re: OT: K-index=2, But Bands Deader Than Doornail?/Try beacons

In reply to this post by Jay Schwisow

In addition, if you can't hear anything on the bands, you should check
your antenna system. I've also found myself trying to receive via the
Ant 2 connection when my antenna was connected to Ant 1 (on my K2).

72,

Jim
W4BQP
K2 #2268

On Tue, 2006-12-19 at 15:31 -0700, Jay Schwisow wrote:

> Stephen/Jeff,
>
> Always take a listen to the HF beacons. This is a great way to see if
> the bands are "open". Right now from Colorado, I can hear W6 and KH6
> on both 15 and 20 meters.
>
> http://www.ncdxf.org/Beacon/BeaconSchedule.html
>
> 73,
>
> Jay - KT5E
>