E-Skip or Tropo Duct?

[Robert Bass]

An unintentional listener sent us this message this morning:

"I'm on the east coast and your radio signal is interfering with WAMU, 88.5, out of Washington, DC. I'm about 60-70 miles from WAMU's transmitter. I can hear you but not them today. What gives?"

Is this a result of E-skip, or Tropo ducting?

R

 

[KPLEXCOMPLEX]

Tropo. The warm weather,t-storms, etc cause it. Its great if you are into dxing. Unfortunately with more "rimshots' moving in etc. DXING has become harder and harder. Send the guy a letter and hope enjoyed the show

 

[Mediafrog+]

Tropo.

Not necessarily. The listener near D.C. is at the right distance for E-skip. I've noticed shortwave conditions have perked up the past few days, so increased ionospheric activity might also be present on the FM band.

The best way to tell is by how steady the signal is--If there is fairly rapid variation in signal level (similar to shortwave) it is most likely ionospheric skip. If the signal is fairly steady over a significant amount of time, it is probably tropo. For instance, here in Houston I have heard central and south Florida both ways.

Long distance tropo is also more likely over (but not limited to) coastal or water paths, and can cover a wide range of signal path distances. E-skip generally brings in stations 800-1200 miles away, but rarely closer.

Such openings usually work both ways, so if someone near D.C. is hearing DFW stations, then DFW listeners are likely to snare some D.C. stations.

 

[Robert Bass]

Tropo.

Not necessarily. The listener near D.C. is at the right distance for E-skip. I've noticed shortwave conditions have perked up the past few days, so increased ionospheric activity might also be present on the FM band.

The best way to tell is by how steady the signal is--If there is fairly rapid variation in signal level (similar to shortwave) it is most likely ionospheric skip. If the signal is fairly steady over a significant amount of time, it is probably tropo. For instance, here in Houston I have heard central and south Florida both ways.

Long distance tropo is also more likely over (but not limited to) coastal or water paths, and can cover a wide range of signal path distances. E-skip generally brings in stations 800-1200 miles away, but rarely closer.

Such openings usually work both ways, so if someone near D.C. is hearing DFW stations, then DFW listeners are likely to snare some D.C. stations.

I am pretty sure this is tropo. We got another DX report from the same general area. The person indicated very strong reception for a quite lengthy time period.

I'd rather see a response to these DX reception reports, that correctly define the cause, than automatically assuming it's E-Skip.

R

 

[Steve Eberhart]

I remember one time years ago we received a cassette from a guy who was listening to Bill Gardner on the air at KVIL in middays ... the guy was in Kansas! The audio was pristine FM Stereo...

 

[Media Mogul]

Check this post out that I put on the Arkansas board.... That might shed a little light on what I was speaking of...

http://www.radio-info.com/smf/index.php/topic,71960.0.html

 

[jd]

Mediafrog provided some good insight on tropo in a previous post. Here's a handy site that actually provides forecasts of "hot" tropo activity: www.dxinfocentre.com/tropo.html Further down that page is an explanation of various reception modes: www.dxinfocentre.com/propagation/tr-modes.htm There's a difference between ordinary tropo and tropo ducting and the author of the site, William Hepburn, explains it well.

Although I don't usually cite Wikipedia as a reference, it has a good article on tropo. But there is also a great explanation of "E-skip" and "F2 skip" in the article titled "TV-FM DX."