Satgen236   Auroral Scatter versus Auroral Es  by GM4IHJ        2nd Oct 93
BID of this msg is SGEN236   Please use that BID if you retransmit the msg

There has been some inaccurate reporting recently in several radio amateur
magazines, whereby some contacts quoted as Auroral Es , clearly were not. 
The reporters are forgeting that Auroral Es propagation is perhaps better
referred to as "Through the Aurora propagation". To get Auroral Es , one
station must be outside the aurora , whilst the other station is inside
the auroral arc or , on the far side of it.
The best way to study Auroral Es and Auroral Scatter ( the more normal
propagation mode ), is to listen to the beacons and signals on the down
links of RS10 (29.358) and RS12 (29.408). They are in similar 1000km high
orbits inclined at 82 degrees, but RS10 is roughly 31 degrees west of RS12
, at their equator crossings. Recently (Sept 93), this has meant that
whilst RS12 crossed the UK going nearly due north and onward east of the
pole towards Siberia, RS10 was coming across the northern UK horizon at
low elevation, from over Labrador across Greenland and then down into
Russia near Novaya Zemlya. Both started above the UK horizon, but only
RS10 at low altitude to the north was Auroral with a typical T1 tone , all
hiss and no note, as expected from a signal back scattered of the southern
face of the auroral oval . As it dropped below the UK horizon the RS10
signal dissappeared as it went further and further south of the aurora. By
contrast RS12 came clear tone south to north up past UK , and met the
auroral oval north of UK, near its LOS horizon, then as it proceeded
further north sub horizon it was heard via clear note Auroral Es until it
was 21 degrees below the UK horizon and over mainland Far Eastern Siberia
at roughly 5400 kms from UK. This type of track heading at 90 degrees
normal through the auroral oval often produces this type of result and
would have afforded excellent communication in Siberia and northern Japan
albeit at an unsociable time.
It is also significant that RS12 has been producing very early warning of
aurora. At 1059 ut on 20th September 93 RS12 was overhead 74N 284W , and
its -4 degree sub horizon signal into UK was very auroral in tone,
presumably reporting a small aurora already underway far below the UK
horizon in the Siberian early evening zone. The actual aurora itself was a
small brief Kp3 event when it finally came round as the earth spin brought
it into UK longitudes at about 1750 ut.
So please try the RS birds if you want some interesting propagation. They
are quite the best thing there is for HF DX warning . What a pity we have
not got Amsats with 7, 14, 21 MHz beacons on them . Then we could really
monitor HF propagation properly. What we need are more HF birds, more
Doves and perhaps a few less digital "dead as a doornail" grossly under
used most of the times I check them , PSK electronic doorstops.

Reminder . All 236 satgen bulletins are available on ASCII IBM DOS
compatible discs if you want to keep them for reference. Or the most
recent 25 are available on one disk, provided you tell me your postal
address .   73 de John GM4IHJ @ GB7SAN