Thought I heard an echo mic on 20m.

[Captain Kilowatt]

Well I was tuning through 20m this morning and caught a QSO between a W1 and a G0 and the W1 had a really noticable echo on his signal. :shock: I thought GREAT just what we need. A 20m CB'er with an echo mic and God knows what the signal looks like on the band. :roll: I was about to tune away in disgust and decided to check propagation to the west.The tribander was pointed northeast at the time. As the beam swung around to the west and southwest the echo on the W1 station became fainter and fainter until it disappeared completely.It was then that I realised what it was.Backscatter. His signal was arriving at my QTH direct from the USA as well as traveling over to the U.K. where a portion was being scattered and reflected all the way back to me again along the same path the UK station was beong heard. The time differance of arrival was what was causing the echo.With the beam pointed to the UK the echo was really bad.I have worked backscatter before but usually just in a situation where you point the beam south to talk north and can't hear the other station on the opposite heading. I remember hearing CB'ers talk about hearing hams use echo mics on the air and I have to wonder if they heard the same thing and thought it was the mic instead of propagation.The only way to tell is by rotating the antenna and listening for a change.

 

[Sonwatcher]

The maximum distance along the Earth's surface that is normally
covered in one hop using the E region is 1200 miles.
A skywave signal sound can be heard like a well-defined echo if it
arrives at your receiver by both short path and long path

 

[park]

I once made contact with a station on 17m that was about 70 miles away. He had a beam and I a half wave dipole. He said he could hear me better with his beam pointed 180 deg. away from me and I could hear an echo on him.

 

[Captain Kilowatt]

The maximum distance along the Earth's surface that is normally
covered in one hop using the E region is 1200 miles.
A skywave signal sound can be heard like a well-defined echo if it
arrives at your receiver by both short path and long path

Yep,short and long path will do it but so will backscatter. Backscatter is differant in that often the longpath can be the stronger of the two signals depending on propagation. With backscatter the stronger signal is always the shorter path with the longer path not being what is known as "longpath" but rather a longer path into a DX spot and returned by a reflection of the incident wave back towards the direction from which it came.

Radio Moscow was an expert at adjusting beam headings and take off angles for delivering maximun signals into their various target areas.They were almost always the strongest signal but not because they were using megawatts.They would monitor the backscatter and adjust the antennas at the TX site for maximum backscatter which meant maximum signal into the target area. I remember seeing the steadu unmodulated carrier slowly waver up and down with each peak being a bit stronger than the last one. Just before programming would start there was a big jump in signal strength and it would stay there for the entire broadcast.

 

[Sonwatcher]

QRN, I agree. I just remembered a question on my General test that referred to prop causing echo. In my case it was a Barjan Echo Power mic with talkback on 6 meters

 

[Captain Kilowatt]

QRN, I agree. I just remembered a question on my General test that referred to prop causing echo. In my case it was a Barjan Echo Power mic with talkback on 6 meters

:roll:

 

[Sonwatcher]

It was an accident. I threw the mic on and was talking to a guy in Kentucky and he kept telling me how nice my mic sounded. Then another guy got on and asked if I had an echo mic on. I looked and the echo was turned on Embarassed to say the least !