Hi all,
Query on QRN versus QRM. LF natural noise levels (QRN) are typically
well above the front end noise in good receiving gear, and there is not
much that can be done to improve matters further. The QRN likely
originates from lightning in the atmosphere. Use of a whip/loop phased
array producing a carioid pattern can improve S/N a little if the
atmospheric noise is mainly from directions well away from the signal
angle of arrival (as verified by Andrew ZL2BBJ and Nat ZL3VN, who
regularly use phased systems for receiving amateur LF signals)
On the other hand, man made noise (QRM) can be a real pain in the rear
end when trying to receive weak LF signals. Keeping as far as is
practicable away from mains power seems to be the best countermeasure.
A well decoupled power supply to an active whip sited down the backyard
can give quite good relief from mains borne QRM at LF.
Bob ZL2CA
Andre' Kesteloot wrote:
Hello LF Gang,
There is nothing that says that my receiver has _got_ to be located
next to my transmitter, is there?
Over here, we are considering finding a qrn-free site, equipping it
properly with a good receiver, taking the whole 2 kHz band and
redistributing to all the members, either on a FM repeater, or on the
internet.
This won't happen probably until the fall, as we are first trying to
put a transmitter on the air!
73
Andre'
*************************************
finbar o'connor wrote:
WHAT A DIFFERENCE WORKING FROM A QRN FREE SITE MAKES.
[...]JOHN /G4GVC HAS MADE A VERY GOOD POINT ABOUT STATIONS
PUTTING OUT GOOD SIGNALS BUT BEING UNABLE TO HEAR VERY
WELL.
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