It seems that the ionograms published by IPS must be valuable in showing how Sporadic E is developing.
A Google has led to only some brief tutorial information on ionogram interpretation. Can anyone suggest a useful
link, please?
And a couple of specific queries:
- what are the thin vertical lines that often occur at the high end of the charts? Noise, meteorites?
- if E bubbles are typically tens to hundreds of km wide, how reliably will the ionograms from stations several hundreds of km apart and sited around the coastline predict propagation on 6m?
Dave VK1DJA
Ionogram interpretation
Re: Ionogram interpretation
Hi Dave,VK1DJA wrote:It seems that the ionograms published by IPS must be valuable in showing how Sporadic E is developing.
A Google has led to only some brief tutorial information on ionogram interpretation. Can anyone suggest a useful
link, please?
And a couple of specific queries:
- what are the thin vertical lines that often occur at the high end of the charts? Noise, meteorites?
- if E bubbles are typically tens to hundreds of km wide, how reliably will the ionograms from stations several hundreds of km apart and sited around the coastline predict propagation on 6m?
Dave VK1DJA
Dave, my interpretation is that the presence of Sporadic E above Ionosondes withing a couple of thousand km is an indicator of the good possibility that they could be present anywhere in the region.
Above is a sounding from earlier this afternoon showing very good Es over Brisbane (telltale indicators are the height around 90,000km, and keep in mind that Es can occur during local night time).
Though there was no good evidence of Es overhead Canberra, I did have some good contacts on 7MHz in the intermediate distance range which suggests probably Es rather than F2 propagation.
Have you read all the educational material on IPS?
Owen
Re: Ionogram interpretation
Hi Dave,
The URSI Handbook of Ionogram Interpretation and Reduction is "the bible" of ionogram interpretation (and of scaling - reading-off - the various parameters).
See this page on the IPS website, where you can download a PDF copy: INAG - Ionosonde Network Advisory Group Home page
http://www.ips.gov.au/IPSHosted/INAG/
Look for this link title: UAG-23A: URSI Handbook of Ionogram Interpretation and Reduction
Es interpretation is in Section 4, from pp105-135. Remember that this covers the sort of ionograms seen from different places the world over, so you won't often see on the IPS ionograms online some of the examples in the URSI handbook.
Es on ionograms is a fascinating subject. For an idea how to interpret the ionograms in relation to VHF propagation, send me an email (see OpInfo on the logger) and I'll send you my paper from the GippsTech Conference 2007: "Sporadic E - turmoil, turbulence and torment".
73, Roger Harrison VK2ZRH
The URSI Handbook of Ionogram Interpretation and Reduction is "the bible" of ionogram interpretation (and of scaling - reading-off - the various parameters).
See this page on the IPS website, where you can download a PDF copy: INAG - Ionosonde Network Advisory Group Home page
http://www.ips.gov.au/IPSHosted/INAG/
Look for this link title: UAG-23A: URSI Handbook of Ionogram Interpretation and Reduction
Es interpretation is in Section 4, from pp105-135. Remember that this covers the sort of ionograms seen from different places the world over, so you won't often see on the IPS ionograms online some of the examples in the URSI handbook.
Es on ionograms is a fascinating subject. For an idea how to interpret the ionograms in relation to VHF propagation, send me an email (see OpInfo on the logger) and I'll send you my paper from the GippsTech Conference 2007: "Sporadic E - turmoil, turbulence and torment".
73, Roger Harrison VK2ZRH
-
vk3six
Re: Ionogram interpretation
Theory does not always explain results...
In this article in 1982 attempting to explain progagation as they knew it then,,,
QUOTE: " Most six metre operators are aware of the Sporadic E seasons .............truncated..
and it is certainly a lot of fun". Unquote.
"However" the author goes on to say there are years close to the peak of the sunspot cycle .....when two more six metre seasons occur during the equinox periods.
Then the autor shot himself in the foot (hindesight) and made a profound judgement.
"This latter season" (October) "whilst very good in the Northern hemisphere does not produce as much DX in the Southern hemisphere and will not be discussed further here."
Could I politely point out that the author was about as wrong as you can get.
Most of the long distance EU DX was worked from VK between OCTOBER and FEB in 1988, 1989, 1990 1991, 1992, 1999, 2000, 2001 and 2002 and 2003.
Maybe the TEP Class 1 and 2 Models fit the model but the F2 prop via multi hops is way out of wack.
SOme even related it to the "whispering gallery effect" of a signal skipping around in the F1 dispersed layer belw the F2 layer.
Sadly no one was rewritten the text books to in anyway explain the repetitive long distance DX worked in the periods between 1989 and 2003.
The European path does not fit the Pacific Model descibed back in 1982 and in credit to the author was the comment
"The propagation is believed to be due to the following reasoning".
However the scribe did acknowledge that
"Most of the dx was not worked by operators who just happended to be there, but by careful observation and study of the band conditions, estimating when the band was likely to open."
Which after all is what everyone is trying to do all the time.
In this article in 1982 attempting to explain progagation as they knew it then,,,
QUOTE: " Most six metre operators are aware of the Sporadic E seasons .............truncated..
and it is certainly a lot of fun". Unquote.
"However" the author goes on to say there are years close to the peak of the sunspot cycle .....when two more six metre seasons occur during the equinox periods.
Then the autor shot himself in the foot (hindesight) and made a profound judgement.
"This latter season" (October) "whilst very good in the Northern hemisphere does not produce as much DX in the Southern hemisphere and will not be discussed further here."
Could I politely point out that the author was about as wrong as you can get.
Most of the long distance EU DX was worked from VK between OCTOBER and FEB in 1988, 1989, 1990 1991, 1992, 1999, 2000, 2001 and 2002 and 2003.
Maybe the TEP Class 1 and 2 Models fit the model but the F2 prop via multi hops is way out of wack.
SOme even related it to the "whispering gallery effect" of a signal skipping around in the F1 dispersed layer belw the F2 layer.
Sadly no one was rewritten the text books to in anyway explain the repetitive long distance DX worked in the periods between 1989 and 2003.
The European path does not fit the Pacific Model descibed back in 1982 and in credit to the author was the comment
"The propagation is believed to be due to the following reasoning".
However the scribe did acknowledge that
"Most of the dx was not worked by operators who just happended to be there, but by careful observation and study of the band conditions, estimating when the band was likely to open."
Which after all is what everyone is trying to do all the time.
Re: Ionogram interpretation
Hi Steve,
I don't recognise the article you're quoting. However, the "equinox seasons" are there every year - but rarely exploited during low SSN years because of the pervasive belief that the DX is only there during high SSN years. Admittedly, the DX opportunities are fewer during low SSN years, necessitating more persistence on the part of operators. And there are fewer operators, because of the pervasive belief . . . self-fulfilling the folk-philosophy.
The author's pronouncement about southern hemisphere 6m DX simply displays a lack of "homework".
I remain unconvinced that the really long-distance DX worked on 6m is actually supported by the simple multi-hop F2 "model".
That which is/has-been worked is serendipitous, but nonetheless resulting from persistence and observation of band "conditions" . . . which really means trawling the available signals around the spectrum of interest - TV carriers, other broadcasters and beacons.
These days - and for the coming solar maximum - online resources have a role, from loggers to online ionograms (to neatly return to the topic of this forum thread
)
73, Roger Harrison VK2ZRH
It depends on which theory is applied to the circumstancesTheory does not always explain results...
I don't recognise the article you're quoting. However, the "equinox seasons" are there every year - but rarely exploited during low SSN years because of the pervasive belief that the DX is only there during high SSN years. Admittedly, the DX opportunities are fewer during low SSN years, necessitating more persistence on the part of operators. And there are fewer operators, because of the pervasive belief . . . self-fulfilling the folk-philosophy.
The author's pronouncement about southern hemisphere 6m DX simply displays a lack of "homework".
The radio amateur "textbooks" in regard to propagation have needed rewriting/updating since the 1970s, in my view.Sadly no one was rewritten the text books to in anyway explain the repetitive long distance DX worked in the periods between 1989 and 2003.
I remain unconvinced that the really long-distance DX worked on 6m is actually supported by the simple multi-hop F2 "model".
That which is/has-been worked is serendipitous, but nonetheless resulting from persistence and observation of band "conditions" . . . which really means trawling the available signals around the spectrum of interest - TV carriers, other broadcasters and beacons.
These days - and for the coming solar maximum - online resources have a role, from loggers to online ionograms (to neatly return to the topic of this forum thread
)73, Roger Harrison VK2ZRH