From Derek, G3GRO, IO91VC,
Had a good QSO with Reino OG5UFO last night starting at 00-45 UTC on
137.00Khz lasting for 20 miutes. He was 549/559 and gave me RST329 then
later RST 539 with some QSB. Reino was almost exactly on the same
frequency within a few Hz of CFH in Canada who at that time of night was S8
with me and completely swamping Reino until I switched in the canceller
loop antenna. Then CFH completely vanished leaving Reino in the clear
with a nice quiet background - fortunately the noise QRM which I often
experience from a nearby British Telecom cable carrying a high speed data
stream was absent. For informtion, Reino suggested that QSLs being
sent direct should be held back until after 29th of Feb.
The signal canceller is working very well with a very simple arrangement.
The plane of the single turn loop antenna runs East-West the size of which
is roughly 8m by 12m slung between two trees. The signal from the loop
is subtracted from the main omni-directional inverted L antenna giving a
resultant cardioid polar pattern with a null which can be steered anywhere
within a 180 degree azimuth sector either to the east or to the west
switched by inverting the phase of the loop relative to the L W.
transmitting antenna. The main use is to cancel Loran QRM but since the
Loran is in the SW direction from me and CFH to the west, both can be
pretty well cancelled at the same time when the optimum direction of the
cardioid is pointed towards the continent.
73 de Derek, G3GRO
IO91VC, 300W, Antenna : 50 m long inverted L up at 16m AGL
| 