I tracked the technical details of my pulse interference down. It’s the
ramp radar at Ottawa airport, nearly 80km from
where I am. The radar rotates at 12RPM, which explains me seeing it
every 5 seconds. The transmitter produces
pulses at about 600Hz, with both 1us and 100us pulses. I got this
from one of their technical people. The transmitter
produces 21.5KW of peak power, into a 32dBi antenna. The sidebands
are suppressed by only 40dB, which is rather
poorer than I’d expect. That means that there may be significant
energy at 1400Mhz being injected into that +32dBi antenna of
theirs. Boo, hiss.
The weather has been lousy for the last couple of days, which curiously
enough has caused the radar interference to
subside. But with the heavy cloud cover and rain, my baseline is
about 5 times wobblier than usual.