FSTG 29/4/2002 1

Scottish Links

Kevin Paulson

Rutherford Appleton Laboratory,

Chilton Didcot, Oxfordshire, OX11 0QX

FSTG 29/4/2002 2

Scottish Links Experiment

► Investigate the effects of sleet and snow on commercial links.

► Monitor link attenuations at several hubs around Dundee.

► Observe high attenuation events with St Andrews radar.

FSTG 29/4/2002 3

The Links

Taybridge Links

Craigowl Links

LinkNumber

Lengthkm

FrequencyGHz

Polarity RainFade0.01%

Comments

0 3.16 22 V 6.0 dB1 7.37 22 V 12.3 dB2 3.46 22 V 6.5 dB Uncalibrated3 12.83 22 V 18.3 dB Uncalibrated4 12.83 13 V 6.8 dB5 4.06 25.6 V 9.7 dB

LinkNumber

Lengthkm

FrequencyGHz

Polarity RainFade0.01%

Comments

0 26.55 13 V 10.3 dB Erratic1 12.7 22 V 18.2 dB Uncalibrated2 27.85 13 V 10.5 dB3 13.03 13 V 6.8 dB4 20.88 13 V 9.1 dB5 12.7 13 V 6.7 dB6 2.04 22 V 3.9 dB7 10.37 13 V 5.8 dB

FSTG 29/4/2002 4

February 7 2002

Overcast and cold with temp. rising from 3 to 6 degrees by afternoon.

FSTG 29/4/2002 5

Taybridge Results 7/2/02

FSTG 29/4/2002 6

Craigowl Results 7/2/02

FSTG 29/4/2002 7

March 10 2002

Temperatures between -2 and 1 degree with sleet and snow.

FSTG 29/4/2002 8

Taybridge Results 10/3/02

FSTG 29/4/2002 9

Craigowl Results 10/3/02

FSTG 29/4/2002 10

Conclusions

► 8 events in the period 1/1/02-21/3/02 where one or more links experience attenuation >A0.01% due to sleet.

► Craigowl experiences more sleet events than Taybridge (and both considerably more than Winchester/Thorne Hill)

► Many of the extreme attenuation events last much longer than predicted by the RAL fade duration model.

► Sometimes extreme attenuation is restricted to a small number of links indicating spatial inhomogeneity in sleet.

FSTG 29/4/2002 11

Attenuation Exceedances Taybridge