Does skywave change vertical polarized beacons

[VK4QB]

Hi all you Gurus,
This is food for thought. Does the vertically polarized transmissions from beacons change to horizontal polarization when reflected from the ionosphere, or is there also some vertical polarized signal still there as well. I don't have a vertical antenna here as well as my beam, and I don't want to turn it on its side just to see.
Brian 4QB

[VK2OMD]

Hi all you Gurus,
This is food for thought. Does the vertically polarized transmissions from beacons change to horizontal polarization when reflected from the ionosphere, or is there also some vertical polarized signal still there as well. I don't have a vertical antenna here as well as my beam, and I don't want to turn it on its side just to see.
Brian 4QB

But is the wave simply "reflected from the ionosphere" as you say?

It isn't, the process is closer to refraction, and polarisation of the wave is changed as it passes through the Ionosphere (Google for Ionospheric Faraday Rotation).

It is most unlikely that the received wave from the vertical beacon is purely vertically polarised.

An interesting question: Does a station at 90° to your beam antenna see a mainly horizontally polarised wave?

Owen

[VK2KRR]

Yes. There is both Horizontal and vertical present. Or should that read, it doesn't matter which polarity you use, vertical or horizontal, the signal on each is very similar.
Alice Springs 2m beacon is vertically polarised and majority of people listen for it with horizontal. I have both vert and horiz and like I said, there is no real difference.
Another fine example would be where in Jan this year VK5GF using a vertical omni was able to work ZL1BT (horizontal) on 2m.
Or where I worked JAs on 6m with a vertical omni.

[VK4QB]

Hi Leigh,
Thanks for that info. What you said about your reception of the Alice beacon is very interesting. From that It seems that any transmissions beyond the ground wave is both polarities.MMMM But I'll enjoy it when it finally gets here again whatever the polarity.
73
Brian 4QB

[VK2OMD]

Brian, my posting was in response to your "reflected from the ionosphere" scenario (eg HF) and is not generally relevant to the Leigh's discussion of 2m propagation where ionospheric reflection (refraction) is not the usual propagation mechanism.

Owen

[vk3six]

Hi all you Gurus,
This is food for thought. Does the vertically polarized transmissions from beacons change to horizontal polarization when reflected from the ionosphere, or is there also some vertical polarized signal still there as well. I don't have a vertical antenna here as well as my beam, and I don't want to turn it on its side just to see.
Brian 4QB

I read sometime polarity reverses/rotates/ and causes the fading amongst other things,
Thats why you can hear it better on vertical than horizontal sometimes and vice versa.
I think.
but then Im an operator of appliances not like Roger.

[VK5BC]

Hi all you Gurus,
This is food for thought. Does the vertically polarized transmissions from beacons change to horizontal polarization when reflected from the ionosphere, or is there also some vertical polarized signal still there as well. I don't have a vertical antenna here as well as my beam, and I don't want to turn it on its side just to see.
Brian 4QB

Last summer 'E' season I monitored 144.1 with 2 radios, one with the vertical yagi, the other with the horizontal yagi. On some occasions I would 1st hear signals with vertical, other occasions the horizontal. Generally signals were similar on either radio regardless of the polarisation being used at the other end but the QSB patterns could be different (i.e. a signal may up on one & down on the other & vice verus). Remember I'm talking Sporadic E not Tropo where polarisation certainly makes a difference.

Brian
VK5BC

[VK1XX]

DONT FORGET FARADAY ROTATION AS A WAVE PASSES THROUGH THE IONOSPHERE!!!!

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