|Polarisation diversity reception on 50MHz|
|Date dd/mm/yy||UTC||Content||km||Propagation mode||File size||Duration||Comments|
||3B9FR in MH10rh
||Diversity working LZ2DF. Strong and then fades out.
||3B9FR in MH10rh
||Diversity working G3ZSS and me. Very weak on vertical.
||ZS4TX/6 in KG47ur||8745||TEP + Es||275kB
||Diversity, working G4FJK.
||ZS4TX/6 in KG47ur
||TEP + Es? (no Es evident though)
||Diversity but very weak on vertical. Rapid phase shifts between H nd V.
||ZD7VC/B in IH74
||Es + TEP or nEs?
||Slightly rough sounding note, with phase changes typical of Es
||C5YK in IK13pk
||Diversity in ssb with gaps edited out. Quite fast phase changes between H and V.
||TZ6BB in IK62ao
||Diversity in ssb, working G4FJK. Fairly stable phase shift between V and H.
||TZ6BB in IK62ao
||Mono only, working me.
||6V7SIX/B in IK14lk||4274
||Diversity. Beacon with slowly drifting phase between H and V.
||6O3A in LJ29an
||cw, Multi hop Es||456kB
||Mono only. Working G4PWA
||FR4NT in LG79pa
||Es + TEP
||Diversity. Working G5WQ who is audible by backscatter as well as direct
||Z21BB in KH52ne
||cw, Es + TEP
||6V7SIX in IK14lk
||Diversity. Remarkably stable with virtually constant phase shift between H and V
||6V7Q in IK14LL
||ssb. Much slower fading and more correlation between H and V than Es propagation
||3XY1D in IJ39dl
||cw cq. Ditto
||GB3LER beacon in IP90jd
||Rapid flutter, stronger on h pol
||OY6BEC beacon in IP62oa
||Rapid flutter, signal strong on both polarisations
||LA8AJA in JP50hp
||Mono only - 57A
||5N7M in JJ39sb
||cw, F2 - 1st qso on 6m F2 for 9 years.
||Mono only - weak signal. 559 then fades out.
||PJ4E in FK52ud
||cw, Multi hop Es||2MB
||Edited highlights - working G3WOS, GM3WOJ, G4RRA, G3TCT
||Working G4EZT. TF/DL3GCS was using a vertical antenna.
||VO1FU beacon in GN37ol
||Multi hop Es
||K1TOL in FN44vg
||cw, Multi hop Es
||Channels swapped: LH=Vert, RH=Horiz. I am transmitting on the vertical.
||PJ2/DJ9ON in FK52lf
||cw, Multi hop Es||591kB
||PJ76 in FK88
||Multi hop Es||551kB
||ssb wkg G0VQY
||PJ76 in FK88
||cw, Multi hop Es||513kB
||cw split in mono, working M0BKL, G3TCT
|1800 approx||MM0AMW in IO75ej||516||cw, Aurora||444kB||57s||working G4WJS - audible by both Ar and direct|
|08/04/10||1243||CS5BLA beacon in IM57px||1534||Es||356kB||45s||Early in Es season.|
|25/05/10||1650||A92IO in LL56fe||5223||Multi hop Es||553kB||1min 10s||working split, intervals between transmissions edited out|
|25/05/10||1717||1B1AB in KM65pi||3345||Multi hop Es||624kB||1min 20s||in QSO with G0CHE|
|04/06/10||1633||A92IO in LL56fe||5223||Multi hop Es||225kB||29s||working me|
|05/06/10||0821||E4X in KM71oq||3758||Multi hop Es||465kB||1 min||working split up 5|
|10/06/10||1918||FY1FL in GJ35qd||6873||Multi hop Es||398kB||51s||working me|
|22/06/10||1507||A71EM in LL55rj||5356||cw, Multi hop Es||485kB||1min 2s||Working me, mono recording only|
|22/06/10||2041||JW9SIX in JQ94lm||2784||Multi hop Es||361kB||46s||Bear Island beacon, vertical ant|
|24/06/10||0845||ST2AR in KK65er||5009||cw, Multi hop Es||465kB||59s||Callers not being heard|
|28/06/10||1612||FS/W6JKV in FK88||6354||cw, Multi hop Es||519kB||1min 6s||Working G5WQ|
|28/06/10||1619||FS/W6JKV in FK88||6354||cw, Multi hop Es||426kB||54s||Working me|
|30/06/10||2035||JW7QIA in JQ68tb||3067||cw, Multi hop Es||446kB||57s||Working me, mono recording only|
|19/07/10||1924||YO4RYU/MM in IM38dh||1665||Es||415kB||52s||Recording with AGC off. G0JHC heard via backscatter on both pols, and others calling heard on V pol.|
|19/07/10||1946||CS5BLA beacon in IM57px||1534||Es||712kB||1min 31s||Recording with AGC off. Breaks in RH channel caused by me checking sub rx. 3 second period sinusoidal fading evident.|
|05/08/10||1457||GB3LER beacon in IP90jd||1008||Es||290kB||37s||Short skip Es, recorded with AGC off|
|05/08/10||1505||GM8LFB in IO88kk||815||Es||346kB||44s||Short skip Es, AGC on|
|06/08/10||1339||N3DB in FM18su||5707||cw, Multi hop Es||351kB||45s||working me|
|Left hand circularly polarised wave||Right hand circularly polarised wave|
In working stations by Auroral backscatter, it is interesting to speculate whether a polarisation diversity receiver might offer some advantage in improved signal to noise ratio. Auroral backscatter occurs in the E region of the ionosphere where ionised particles move along lines of the geomagnetic field. The scattering from such field-aligned particles requires a particular geometry between transmitter and receiver, and this has been covered elsewhere in detail.
A search of the academic literature online reveals a number of experiments, some early ones in 1954 as well as more recent work eg Ref 1. This reference includes some interesting visualisation of the received signal polarisation and its variation over quite short periods of time.
There are two rather nice graphs showing first a highly polarized return, and in the second an almost completely depolarized one.
Here is their diagram of a strongly polarised return at 0430 to 0435UTC
They interpret the
strongly polarised return as implying
...a small scattering volume and/or a small number of discrete scatterers located close to one another...
Here is a depolarised return at 0345 to 0350UTC on the same day – ie 40 mins earlier.
They interpret this to
mean that the depolarized wave is
...coming from a number of individual scattering volumes within the scattering region (i.e., the effective radar viewing region), which are each influenced differently by Faraday rotation to and from the scattering region
How does this help us to work Aurora on 50MHz? It means there can sometimes be benefits in using diversity reception but this will not perhaps be typical.
Ref 1. Polarization of auroral backscatter at 50 MHz G. C. Hussey, J. A. Koehler, and G. J. Sofko; Radio Science, Volume 32, Number 2, Pages 541-555, March-April 1997