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Author Topic: Es propagation lowest freq limit  (Read 4352 times)
N1AEP
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Posts: 5




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« on: April 08, 2017, 12:03:00 PM »

How low in the frequency spectrum can Es propagation occur? Does it ever happen on, say, 20m?

Also, when a band like 20, 17, 15 or 10 is open, how can one tell if it's E or F layer propagation occurring?

Can long Es or multihop Es be distinguished from F?

Thanks for any replies.
73
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W6RZ
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Posts: 127




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« Reply #1 on: April 08, 2017, 02:56:42 PM »

This ionosonde from June of 2015 would suggest that Es propagation occurs down to at least 3 MHz. During that event, you could expect propagation from 3 MHz up to 60 MHz of varying path lengths (longer paths at higher frequencies).

It's difficult to tell exacty what mode is being propagated, but if you're hearing/working stations very close in on 20m, then it's likely to be Es.

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W4KYR
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Posts: 1453




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« Reply #2 on: April 08, 2017, 03:07:13 PM »

How low in the frequency spectrum can Es propagation occur? Does it ever happen on, say, 20m?

Also, when a band like 20, 17, 15 or 10 is open, how can one tell if it's E or F layer propagation occurring?

Can long Es or multihop Es be distinguished from F?

Thanks for any replies.
73

By distance. Some months ago there was an F skip opening to South America and California on 10 meters. Also at the same time there also was an E-Skip opening with Florida and Vermont.
coming in.

Vermont and Florida is within E-Skip range here in Kentucky. E-Skip is anywhere from 700 to 1400 miles.

California 2500 miles and South America 5000 miles are within F skip range.

Multi-hop E-skip can occur during the primary E-Skip season late May - July. (And there is a lesser E-Skip peak around  December and January.)

Usually there is already an E-Skip opening going on and multi-hop E-Skip forms. This will account for very unusual reception of TV or FM broadcast making the trip all the way over to Europe as it has done on several occasions.

Here is one example of WHCR 88.5 Bangor Maine making it all the way to the UK at a distance of 2710 miles or 4360 KM! The reception was multi hop E-Skip. Notice the date, it was June 26 2003, right smack in the middle of the E-Skip season here in the Northern Hemisphere.

https://www.youtube.com/watch?v=ga56hsHvTCg

Other less extreme examples are transatlantic multi-hop 6 meter reception during the prime of the E-Skip season. This is not F Skip because it is in the middle of the E-Skip season and during a low F Skip period. E-Skip is not dependent on the solar cycle, but F Skip is.

Distance is the easy way to tell...
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N1AEP
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Posts: 5




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« Reply #3 on: April 08, 2017, 04:29:16 PM »

Thank you for the kind replies, William and Ron -- all very fascinating stuff indeed.  I had wondered about E-layer activity on lower freq's. Sometimes I have heard close in sigs on 20 which faded rather rapidly in and out or got fluttery and it almost reminded me of 6 or 10 m E openings. 

That recording of the Bangor FM broadcaster was wild! On a related note, anyone know if there has been any transatlantic activity noted on 2m yet? I recall there was a beacon set up. at least at one point years ago.   

73
Joel
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W4KYR
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« Reply #4 on: April 08, 2017, 05:22:42 PM »

Thank you for the kind replies, William and Ron -- all very fascinating stuff indeed.  I had wondered about E-layer activity on lower freq's. Sometimes I have heard close in sigs on 20 which faded rather rapidly in and out or got fluttery and it almost reminded me of 6 or 10 m E openings. 

That recording of the Bangor FM broadcaster was wild! On a related note, anyone know if there has been any transatlantic activity noted on 2m yet? I recall there was a beacon set up. at least at one point years ago.   

73
Joel

I don't believe there has been any transatlantic 2 meter. Usually if the E-Skip does make it to two meters, it is one hop and kind of short lived. 

The fluttery signal could have been E-Skip back scatter. But the more common cause for fluttery signals on the HF bands is due to auroral conditions.

https://www.electronics-notes.com/articles/ham_radio/amateur-propagation/auroral-propagation.php

By the way, there have been cases of Transatlantic TV-DX as well (during the analog era).  Dxers in Europe have multi-standard TV sets or were able to tweak their European TV sets to receive American TV such as in the case of a TV DXer in Portugal receiving Orlando FL channel 2.

"DXTV Reception of WESH TV Ch 2 in Portugal"

https://www.youtube.com/watch?v=zzhyzrC2xSM

 
Now there have been cases where the E-Skip MUF has reached TV channel 13. https://en.wikipedia.org/wiki/TV_and_FM_DX#Notable_sporadic_E_DX_receptions

Tropo ducting can result in further distances than multi E-Skip...

Such as the legendary cases of tropospheric ducting from Hawaii to California and not just on 2 meters, but even higher up in frequency. And it wasn't just a 'one off' event as it has happened quite a few times already. Here are some interesting all time records. The longest distance was nearly 3000 miles for tropospheric ducting!

http://dx.qsl.net/kh6hme/
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W8JX
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Posts: 11270




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« Reply #5 on: April 19, 2017, 04:46:33 AM »

How low in the frequency spectrum can Es propagation occur? Does it ever happen on, say, 20m?

Also, when a band like 20, 17, 15 or 10 is open, how can one tell if it's E or F layer propagation occurring?

Can long Es or multihop Es be distinguished from F?

Thanks for any replies.
73

This is a bit misleading because it is not so much the lower limit of E layer reflection as it is D layer absorption which starts climbing on 40 m and increases as you go lower in frequency and is a complete wall on 160m and nearly so on 80 during daylight hours. At nite the D dissipates and the frequency needed to get thru it decreases. 20m and above is not effected by D layer and that is why DX is possible during day on those bands with MUF is high enough on E and F layers to allow multiple hops.
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Ham since 1969....  Old School 20 WPM Extra
G8YMW
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Posts: 606




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« Reply #6 on: April 21, 2017, 10:08:30 AM »

How low in the frequency spectrum can Es propagation occur? Does it ever happen on, say, 20m?

Also, when a band like 20, 17, 15 or 10 is open, how can one tell if it's E or F layer propagation occurring?

Can long Es or multihop Es be distinguished from F?

Thanks for any replies.
73

This is a bit misleading because it is not so much the lower limit of E layer reflection as it is D layer absorption which starts climbing on 40 m and increases as you go lower in frequency and is a complete wall on 160m and nearly so on 80 during daylight hours. At nite the D dissipates and the frequency needed to get thru it decreases. 20m and above is not effected by D layer and that is why DX is possible during day on those bands with MUF is high enough on E and F layers to allow multiple hops.

In the main, that is correct but I have heard echoing on 1215 kHz while I've been driving around Doncaster and the only thing I can think of is ground wave and sub critical frequency ionospheric propagation and being straight up / straight down, the D layer would have less effect.
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73 de Tony
Windows 10:  Making me profane since March 2017
W8JX
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Posts: 11270




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« Reply #7 on: April 21, 2017, 11:34:34 AM »

In the main, that is correct but I have heard echoing on 1215 kHz while I've been driving around Doncaster and the only thing I can think of is ground wave and sub critical frequency ionospheric propagation and being straight up / straight down, the D layer would have less effect.


This is why 80m has maybe a few hundred miles or so range during day because only very high angle waves that penetrate less D layer than low angles can make it through and it is even steeper for 160m or lower to have a chance at it. 40m is not absorbed as much and can get through on lower angles and can reach up to 1000 miles or so on E's during the day.
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Ham since 1969....  Old School 20 WPM Extra
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