Propagation For LW Broadcast Band DX

[gccradioscience]

At night I get radio stations from Europe and other countries on the longwave bands with my YB-400 PE, which I have done successfully in 2005. I tried to find information about longwave radio DX propagation for nighttime DX still difficult. Is it the groundwaves bouncing off the curvature of the Earth off the salty waters cause salt water conducts electricity? When is the best time to tune into the European broadcasters? Everything I see mostly is AM broadcast DX which is MW.

Adam E.

[NW7US]

I will try to post an in-depth reply within the next few days, or at least within a week's time. The next few days are pretty busy... but I think I can help with some information, once I have time to sit and write out my thoughts.

Thanks for posting the question!

73 - Tomas

[K5TEN]

At night I get radio stations from Europe and other countries on the longwave bands with my YB-400 PE, which I have done successfully in 2005. I tried to find information about longwave radio DX propagation for nighttime DX still difficult. Is it the groundwaves bouncing off the curvature of the Earth off the salty waters cause salt water conducts electricity? When is the best time to tune into the European broadcasters? Everything I see mostly is AM broadcast DX which is MW.

Adam E.

http://www.lwca.org/ is the best source of longwave stations, propagation, and tips.

In a nutshell though: The parts of the ionisphere that govern whether you hear a low band station or not are the D and F layers. During the hours of daylight, the D layer, energized by the sun's rays, gobble up RF after it hits the D layer and will not let it "hop" further than local or regional areas. At night, the D layer is gone, and low band signals re free to hop as far as their original RF energy and conditions will allow.

"Gray Line" is the time of day when the D layer is gone (or not yet energized) and provide the absolute best low band propagation from any area that is also in a Gray Line zone--Gray Line is the twilight time at sunrise and sunset. You can easily communicate half way around the earth at this time of day when conditions are good.

Radio signals DO differeciate between ocean and earth and bounce the same way off both, except water has the advantage of being a more stable surface. Stations nearby or surrounded by salt water do have a propagation advantage, in that there are fewer obsticals (mountains, hills, mesas, etc.) to get in the way of the signal's path. The lower the frequency the less obsticals matter... the higher the frequency (like VHF and UHF) even buildings can degrade a signal.

Some say pure brute force of hundreds of thousands of watts of RF power are what get the signal through, but transatlantic and transcontinental contacts have been made by VLF stations using only 1 watt and an extremely short antenna. Experimenters (no licence required) can operate in the .136 mHz band with 1 watt and a 50' antenna. Many have made amazing contacts---and it all depends on propagation and conditions at the time.

You did not say what your location is, so advising you on the best time to DX for EU LW stations will be difficult.

But, for example, if you were in Erie, PA, I would recomend that you have your station on and ready about a half an hour before your local sunset, and then most the night until about 0630Z, where best peak should happen again. After 0630Z (GMT) your window of opportunity is over, because EU stations will be in direct sunlight and the D layer will once again begin to gobble up the reflected signal.

If you REALLY want to increase your chances, you will need to make a change to the "DX " "reel" antenna on the Grundig YB400PE. If you post back here that you are interested, I will post how to do it. It's a matter of turning that into a real "DX" antenna that goes outside.

That Grundig is a fine reciever and is grossly under rated. I have one and will not part with it.

Good Luck!



73



Bruce
K5TEN

[K5TEN]

I have been thinking a lot about it, while http://www.lwca.org/might be your best source for Longwave experimenters, UTES, and nav beacons, your best luck for EU LW stations, this Greeke dude has some good links: http://www.qsl.net/sv1xv/lw.htm, if you land some these Armenian stations I'm going to buy you a beer: http://radiostationworld.com/locations/Armenia/radio_websites.asp, and here's where you can search for frequencies by country: http://radiostationworld.com/europe.asp.

The BEST source is the "World Radio & Televison Handbook", whitch is THE authority of all broadcasters worldwide. It's about 300 pages and runs about @$25 US before shipping, but depending on where you live, you can get aa used copy on ebay pretty cheap delivered. I just bought one there and am awaiting delivery. The good thing is that once you buy one, the info stays pretty accurate for 5 or 6 years....except for 3rd world countries with a high government turn-over rate.

Good luck, bro. Hope it helps!


73


Bruce
K5TEN