Seeing double on QRSS grabber…

January 9, 2012 | Amateur Radio, QRSS | By: Mark VandeWettering

Here is a snapshot from my QRSS grabber earlier today. You might want to click it to see it full size:

I’m curious: what phenomenon is causing the strong line doubling of the signals near the bottom? Note: not all the signals demonstrate this phenomenon, and it’s relatively rare, and commonly just fades away. Also note that the signal at the top does not show this line doubling. I suspect all the signals which are line doubled are in New Mexico.

Bonus question: I keep seeing a small wiggle like the one around 10.139975 or so, starting on 10 minute boundaries and lasting for about one minute. Anybody have any idea who that is?

Comments

Comment from WY7A (Eric)
Time 1/9/2012 at 6:39 pm

Slight frequency shift due to magnetospeheric ducting?
http://folk.uio.no/sverre/papers/2009_MagnetoDucting-QST-LA3ZA.pdf

Comment from Peter Marks
Time 1/9/2012 at 7:52 pm

Doppler shift due to an aircraft flying towards or away from you maybe? how long does it last?

Comment from KC2UEZ
Time 1/12/2012 at 2:51 pm

Maybe you are receiving the long and short path of the signal?

Comment from Myles VK6ZRY
Time 2/5/2012 at 3:10 am

Just a simple multipath signal due to auroral effects.
Its temporary won’t happen again for at least a week