Topband: QRM from ASIA on TOP BAND

VR2BrettGraham vr2bg at harts.org.hk
Thu Oct 13 19:44:56 EDT 2005


My guess, having not heard anything myself, is that this might be
from PLA Navy northern fleet equivalent to their South China Sea
base on Hainan that looks to be the source of 40 & 80m OTH
radar (based on DFing from ZL4, DU, HS, VR, W7, JA3, etc).

If it is from PRC, then in VR we have probably the best chance to
do something about it, provided the signal causes harmful
interference to a properly licensed station & the signal is not of
a service that belongs there.

On the other hand, seeing how at least one other significant
first world country that thinks highly of itself in the area of
rule-of-law intrudes all the time, there remains the chance of
application of if-they-do-it-then-we-will-too logic.

This has been the year of the Chinese intruder, with OTHR on
10m from Paracels, CODAR back on 12m from somewhere in
4/5-land, Hainan laying waste to 40 (this just after VR got access
to 7.1-7.2 Mc after we learned the PLA vacated it - they then jam
whole band in retaliation?) & the same on 80.  Now 160?  Sheesh!

On the local front, historically all amateurs here had very strong
feelings about intruders, but strangely quiet on this one.  In
addition to any reports to IARU Monitoring Service one can
provide, be sure to thank the next greater China station you work
for ignoring international agreements & trashing the bands.

Spread spectrum intruders are everywhere - the best example we
have is some failure of a British Forces link here that laid waste
to 20-10m & beyond.  On LF, it isn't easy with the QRN to tell, but
sometimes I feel that there is something like this on the low end
of 80 - on higher bands a few moments of tuning or one quick look
with a spec-an can be rather surprising.

The folks in 5B might just have some tips on how to live with spread-
in-your-face, along with close proximity to pulse QRM from OTHR.
Since under ITU-RR just about anything seemingly can be explained
away under "national prerogative" yet is becoming so commonplace
now, perhaps the strategy should be how to live with these sorts of
things.

73, VR2BrettGraham



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