ARRL

AM BCI to Amateur Receivers

Introduction

It's true that a nearby 50 kW AM station can severely affect most ham receivers. However, this is often due to an inherent design defect--modern receivers with DC to daylight coverage typically rely heavily on low pass filtering, with some help from wide bandpass filtering. This is a cost tradeoff--it just isn't practical to put tight bandpass filtering and cover the entire HF spectrum. There are a few exceptions--the Elecraft K2 has tight bandpass filtering--but doesn't have a general coverage receiver. Another example is the Ten Tec Orion, which also covers just the ham bands. One option is to buy external bandpass filters--they are sold by Top Ten Devices and Dunestar for multi-transmitter contest stations. I have published articles on building tight bandpass filters.

Articles

Sep 1998 QEX

57

A Narrow 80 Meter Band-Pass Filter
(RF)

Lau, Zack, W1VT

Nov 1998 QEX

58

A Narrow-Bandwidth 40 Meter Band-pass Filter
(RF)

Lau, Zack, W1VT

Apr 1992 QST

75

Eliminating AM-Broadcast Interference on 160 Meters
(Hints and Kinks)
Keywords: AM RFI 160 METER

Lau, Zack, KH6CP