[Prev][Next][Index][Thread]
Re: (meteorobs) Overdense or Es?
Hi.Shelby
Good question to what I observed 11UT-14UT June 5.From
all the e-mail I received, all the web sites I have
been told to look at the basic question has still not
been answereddot can the human ear tell the difference
between sporadic E layer and radio meteor events in
the commercial FM band? From what I have researched
there is no clear cut view.If it is impossible those
who only observe by manual counts will be greatly
disappointed.My issue is that many e-mail and web
sites come straight out and say Sporadic E layer is
triggered by meteor activity.With this information in
mind,May and June are the peak periods for daylight
meteor activity.Also the strongest daylight radio
meteor shower of the year happens in this time
frame.From what information I have seen this is also
one period of the year for active sporadic E layer.To
me it is not much of a leap that the two phenomonons
are related at his time. This having been said should
it not be possible for those who have this information
to see if there was a time relationship between
observed sporadic E layer peaks and peak active in the
radio meteor record from the automated stations for
the day in question. Also from the very limited radio
meteor data and sporadic e-layer data I have seen or
heard June 5 was a some what active time period
leading up to the Arietids maximum. This is my
personal view and is based on very limited data and
information.I could be very wrong. I have seen no
posting on when the peak happened. From what
information I have read on the daylight Arietids this
shower has a filament type structure or multiple
streams and still some questions remain open on this
shower. It is only a question of which view you wish
to except. Once again thanks to all on the e-mail
list for your replies and help.
Clear Skies and Good Listening
Thomas Dorman
Far West Texas Sky Watcher
--- "Shelby Ennis, W8WN" <w8wn@arrldot net> wrote:
> You wrote:
> >Some have
> >suggested that this was spordic E layer that I
> have
> >been observing.If this is spordic E layer then it
> >mimics identically radio meteors in the FM band
>
> First guess would be Es, as this is the start of the
> peak season.
> The Europeans have had Es openings every day for the
> past week, including a
> HUGE opening a few days ago. See maps at
> http://www.vhfdxdot de/
>
> However, I have been monitoring TV Ch 2-5 all week
> for Es, and have seen
> very little to none. (One note here - I'm in KY,
> and, from the maps
> published over the years, I'm in the area that is
> right under much of the
> most intensely ionized Es clouds! Even elevating
> the antenna still does no
> good on 144 MHz when they are this close. So I
> could have missed something).
>
> For meteors, they have been fair recently. Reports
> indicate that there
> were a more overdense bursts than usual about a
> month ago, and heard
> several nice ones today. Nothing exceptional, tho.
>
> The ionization is at the same altitude, and thus, at
> a given frequency,
> appears the same, whether caused by Es or meteors.
> Overlapping overdense
> bursts can sound exactly the same as weak Es.
> Strong Es, and separated
> overdense bursts, sound very different.
>
> There are several different causes of mid-latitude
> Es. One of these is
> meteors (have had several Es openings on 50 MHz
> during Leonids, and during
> Perseids of a few years ago; biggest was said to
> have been the '46
> Giocobinies). This morning on 50 MHz I had a trace
> of Es, enhanced tropo,
> with a number of good pings and bursts superimposed
> on the signals.
>
> How hard it can be to tell the difference between Es
> and overdense bursts
> depends primarily on the frequency being used and
> the equipment. There
> have been times when I was not sure for awhile (50
> MHz), tho only once or
> twice have I been fooled on 144 MHz. I don't
> monitor the FM BC band for
> this, but do monitor TV Ch 2-5 for Es.
>
> There has also been a running argument recently
> about just where a
> background of overdense bursts leaves off and Es
> begins....Then, with
> field-aligned irregularities thrown in and a couple
> of other propagation
> mechanisms that are related to all this, it becomes
> fascinating!
>
> What did you hear?
> I dunno!
> But hope I get to hear some of it!
> Shelby, W8WN
>
> The archive and Web site for our list is at
> http://www.meteorobs.org
> To stop getting all email from the 'meteorobs'
> lists, use our Webform:
> http://www.meteorobs.org/subscribe.html
__________________________________________________
Do You Yahoo!?
Yahoo! - Official partner of 2002 FIFA World Cup
http://fifaworldcup.yahoo.com
The archive and Web site for our list is at http://www.meteorobs.org
To stop getting all email from the 'meteorobs' lists, use our Webform:
http://www.meteorobs.org/subscribe.html
Follow-Ups:
References: