On 1/14/2013 11:05 AM, Al Lorona wrote:
There are at least two other ways of knocking down interference from nearby AM broadcast stations. Each requires the choice of a particular type of antenna.
The BEST way to kill AM broadcast interference coupled via the antenna is with a high pass filter. This concept is far from new -- it's been around since the 1920s. When I lived in Chicago, I used the ICE model BCB, which is pretty decent. It's rated for 100W. When the ICE owner/engineer died a few years ago, the company was taken over by one of the employees under a different name.
WX0B (Array Solutions) was a distributor for ICE, and is selling AM broadcast filters built by W3NQN. One model is designed for receive only, so would be used at the RX antenna patch point with a K3. It is a VERY sophisticated filter, designed for VERY sharp cutoff so it can eliminate stations at the very top of the AM band just below 160M. It sells for $225. Another is rated for 150W, with a less sharp cutoff (but still a VERY good filter), and sells for $189. W3NQN filters are pretty much the Rolls Royce of filters.
Array Solutions also builds their own RX only filter for $56. The cutoff is not nearly as sharp nor as deep as the W3NQN filters, but would likely be sufficient if your interference is below about 1300 kHz.
http://www.arraysolutions.com/Products/BCB%20RF%20Filters.htm 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
