(and an exploration into local noise sources) After moving out of a tiny unit into a house I finally had the opportunity to throw a bit of wire into some trees and connect it to my radio. Easy interstate contacts were now available, but there was something nearby making obnoxious noise every 60kHz on HF: […]
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Category: Radio Interference
Anything related to QRM
Why authorities only worry about odd-order IMD?
Why is it that ACMA only worry about odd-order IMD when measuring? 3rd & 5th in particular? Why not the evens? Matt (25-Jan-2017): 2nd order IMD products (eg. f1+f2) will occur well away from your desired signal, and are easily knocked out by your bandpass filter. However, 3rd order IMD products (eg. 2*f1-f2) will fall very […]
Lazy Sundays (hunting QRM)
Everyone has a different idea of Lazy Sundays. For Tim VK2BT, Geoff VK2AVR, Charlie VK2GMT and El Presidente (Carlo) VK2MXC, this past lazy Sunday was an opportunity to chase some interference problems. Our VHF repeaters (analog and DSTAR) have had an issue recently – when both are keyed there is audible “splatter” on the analog tail […]