Snow and ice is transparent to HF. When I was in Antarctica we had an
ice depth radar sounding programme. A DH Twin Otter would fly at 50 feet
above the snow surface as indicated by the radar altimeter and beneath
the wings were a couple of 70Mhz dipoles, TX and RX. The 70MHz TX pulses
penetrated to the underlying rock. Take one height from the other, ice
depth.
Fantastic flying that was.
It is mentioned in the ARRL Antenna Handbook that a closed loop array
like a Sterba curtain could be could be fed with a low voltage DC or AC
current to heat the wire to relieve it of accumulated snow and ice.
Regards,
Mike VP8NO
On 15/12/2020 14:45, David Haines wrote:
Update:
With one-quarter of one leg of the dipole still under ice, I got a
reception report from PSKReporter on FT8 with 2 watts to Italy. That
shouldn't work, should it? Maybe the ice doesn't matter?
KD5VXH recalled a discussion in QST on this very subject, where 400W AM
melted the ice on one leg of the dipole (fed by coax), but not the other.
'
You can follow the controversy in May and July 1960 letters in QST!
david
KC1DNY
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