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Loggings => Longwave Loggings => Topic started by: NJQA on July 09, 2019, 0907 UTC

Title: LF propagation
Post by: NJQA on July 09, 2019, 0907 UTC
The August 2019 issue of QST has an interesting article on LF propagation.  The author analyzed his experiences on NDBs over 3 years.  I havenít looked at the article in depth yet but two of his takeaways for his Texas QTH were that the best month was October and that the sunrise enhancement provided the best reception.
Title: Re: LF propagation
Post by: jFarley on July 09, 2019, 1531 UTC
From your description of his takeaways, I think the author nailed it on both regards.

A veteran NDB DXer did a study of RNA logged NDB distance vs month of the year.  There was a definite peak around October.  I cannot find this post at the moment, and I cannot remember if this was for logs at the listener's QTH, for NA, or for the northern hemi.  But this is true for observations from here in Chicago.  When the season starts around September, it helps to be ready and have your bucket list prepped and goals set because things get going fast.

This does not preclude long haul DX at other times of the season.  For Chicago, the longest DX will typically come from Brasil and 100 watters at around 8000 km may be heard sporadically thru early March.

While there are generally geographical clusters of reception noted during sunset enhancement conditions, by far and away peaked reception due to sunrise enhancement at the TX is one of the most powerful NDB DX scenarios.  Because Chicago is situated on the middle coast of the USA, SRE reception of beacons from AZ to GA is noted as the sunrise terminator tilt changes with the seasons.

Last season, general NDB DX conditions were anticipated to be very good due to low solar activity, and no one was disappointed.  We are really looking forward to a repeat of conditions this coming fall.

Goals here include Iceland and Argentina, and we are hoping that the great gods of prop cooperate.
Title: Re: LF propagation
Post by: ChrisSmolinski on July 10, 2019, 1252 UTC
DGPS DX should be good this October, with the upcoming Great USCG DGPS Massacre (with full orchestration and five part harmony and stuff like that) knocking a lot of US stations off the air Sept 30th.
Title: Re: LF propagation
Post by: jFarley on July 10, 2019, 1452 UTC
Phase 2 of the Canadian NDB Massacre is sked for 10 October 2019.  This will open up a couple of possibilities.  NA listeners will have a real shot at LT 305 (Alert, NU) due to the sked closure of YQ 305 (Churchill, MB) which dominates here.

Noting that my local DGPS pest Mequon 304 is currently off, but it is no the the time of year to capitalize on this.  IIRC, Mequon is due to go off in the fall.  Good riddance, and bubbye now.

Title: Re: LF propagation
Post by: ChrisSmolinski on July 10, 2019, 1519 UTC
The Alaskan DGPS stations will remain on the air until the 2020 Massacre, so I'll have more shots to receive them (I have routinely receive several of them in winter). Unfortunately the two Hawaii DGPS stations both go QRT this year. I have received one of them twice I believe.  Hoping for some new European DGPS this winter, with the reduced number of US stations as well as the solar minimum conditions.

I'm sure the USCG is hard at work repairing Mequon so they can get it back on the air in time to pull the plug.
Title: Re: LF propagation
Post by: pinto vortando on July 18, 2019, 1527 UTC
Just got my QST yesterday, good to see some discussion of LF propagation.
Too many textbooks talk about groundwave and leave it at that.
Didn't notice what the author used for RX and antenna but whatever he
used, he did well to log 400+ beacons in three seasons. 
Title: Re: LF propagation
Post by: Looking-Glass on July 19, 2019, 2134 UTC
Can this be viewed on line?  QST magazine not available in Australia book and magazine outlets, would like to have a read...thanks :)
Title: Re: LF propagation
Post by: pinto vortando on August 18, 2019, 1922 UTC
The author of the article found that October was best month for number of beacons logged from his QTH.
Around here, beacon season is fully underway by October, but the best months have been December and January
with another peak in March.
Title: Re: LF propagation
Post by: Josh on August 19, 2019, 1935 UTC
I have a suspicion that latitude of the rx site will be the determiner of best propagation times.... for that rx site of course.
Title: Re: LF propagation
Post by: pinto vortando on August 19, 2019, 2156 UTC
I have a suspicion that latitude of the rx site will be the determiner of best propagation times.... for that rx site of course.

The terminator will move faster the closer one is to the equator so greyline enhancement
will be shorter closer to the equator if my reasoning is correct.

Also, the period of nighttime darkness during winter will be longer the further north one is located.

Are there other considerations based on latitude ?
Title: Re: LF propagation
Post by: Josh on August 19, 2019, 2245 UTC
Auroral zone.
Title: Re: LF propagation
Post by: pinto vortando on August 19, 2019, 2306 UTC
Auroral zone.

Does auroral reflection affect longwave frequencies ?
Title: Re: LF propagation
Post by: Josh on August 19, 2019, 2322 UTC
Iono, something I seem to recall, mebbe it eats em?