I have the KXV3 option installed to facilitate my receiving antennas for the low bands: beverages and K9AY loops. Recently I noticed a carrier on 1820.7 kHz, on the frequency of JW/SM0MDG. AM-modulation, sounded Chinees. It was strong on the K9AY loops (all directions) but not that strong on most of the beverages. It started around 07:00 UTC and stopped a few hours later. Some other "strange" signals could be detected as well, however, to weak to identify the stations.
I found out that the "interference" was from a Chinees broadcast station transmitting on 11855 kHz. This is the image frequency of 1820 kHz (local osc. of the K3 is 10035 kHz). And, on my loops the 11855 kHz signal was very strong, 40-50 dB over S9! The strongest station on that broadcast band. K9AY loops have great bandwidth... Early in the morning, when the 160 meter band is still open to the west, the 12 Mhz broadcast band also opens from the east. So: be aware! In the K3 manual, page 40, the manufacturer makes a statement about this fenomena. I already had a low pass filter, cutt-off at 4 Mhz, solving the problem. My conclusion: Low band dx-ers, using the KXV3 option for receiving antennas such as loops and beverages should consider to insert a low-pass filter to improve the image rejection. Kees, PA0CLN _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
