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Author Topic: LF propagation  (Read 1815 times)

Offline NJQA

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LF propagation
« 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.

Offline jFarley

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Re: LF propagation
« Reply #1 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.
Joe Farley, Near Chicago
SDR-IQ / R8 / R7
Remote Resonant Loops for HF and LF / ALA 1530
Active 60" Whip / PA0RDT
QSLS appreciated to:    jfarley44@att.net

Offline ChrisSmolinski

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Re: LF propagation
« Reply #2 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.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline jFarley

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Re: LF propagation
« Reply #3 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.

Joe Farley, Near Chicago
SDR-IQ / R8 / R7
Remote Resonant Loops for HF and LF / ALA 1530
Active 60" Whip / PA0RDT
QSLS appreciated to:    jfarley44@att.net

Offline ChrisSmolinski

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Re: LF propagation
« Reply #4 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.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline pinto vortando

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Re: LF propagation
« Reply #5 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. 
Das Radiobunker somewhere in Michigan

Offline Looking-Glass

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Re: LF propagation
« Reply #6 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 :)
Hermitage Flat, NSW.

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Yaesu FT-2000D, ICOM IC-736 HF/50MHz, ICOM IC R75 & Tecsun S-2000 to 450 feet of wire, and a multi band vertical of dubious reliability.

Offline pinto vortando

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Re: LF propagation
« Reply #7 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.
Das Radiobunker somewhere in Michigan

Offline Josh

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Re: LF propagation
« Reply #8 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.
Conveniently located near Vincennes Indiana.

Offline pinto vortando

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Re: LF propagation
« Reply #9 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 ?
Das Radiobunker somewhere in Michigan

Offline Josh

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Re: LF propagation
« Reply #10 on: August 19, 2019, 2245 UTC »
Auroral zone.
Conveniently located near Vincennes Indiana.

Offline pinto vortando

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Re: LF propagation
« Reply #11 on: August 19, 2019, 2306 UTC »
Auroral zone.

Does auroral reflection affect longwave frequencies ?
Das Radiobunker somewhere in Michigan

Offline Josh

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Re: LF propagation
« Reply #12 on: August 19, 2019, 2322 UTC »
Iono, something I seem to recall, mebbe it eats em?
Conveniently located near Vincennes Indiana.