AboutChris Bushman Expertise I have been an amateur radio operator for about 36 years.
Experience In real life I manage a small motion picture film lab in Hollywood. I've been a fireman, a teacher of English in Okinawa, a personal computer tutor.
I am an Advanced Class Ham radio operator using my originally issued callsign WB6EEQ. I have operated for extended periods of time from Okinawa (KR6FX & KR6OP), Texas (K5VXG), and Mississippi (K5TYP).
While in the Air Force, I was a Manual Morse Radio Intercept Operator.
BS Zoology, UC Davis
Member, Society of Motion Picture/Television Engineers http://www.smpte.org/ - Member, American Radio Relay League http://www.arrl.org/ - Member, Quarter Century Wireless Assn. http://www.lockport-ny.com/radio.htm - President, Zen Nippon Airinkai, So Cal Chapter http://ourworld.compuserve.com/homepages/Chris_Bushman/ - Member, Maltose Falcons Homebrewing Society http://www.westval.com/mfalcons/ - Alumni, American Brewers' Guild http://www.abgbrew.com/
Expert: Chris Bushman Date: 7/21/2007 Subject: 10m radio and groundplane vertical
Question QUESTION: I recently dusted off my RCI and bought a new A99. Everything worked great. Today I bought the groundplane radials for it and now I am getting interference on my tv set nowhere near my antenna or the tx/rx. I hate to upset the neighbors as well. Is there an inexpensive way to correct this issue. FYI... From ground to tip of the A99 is about 46ft. with a 6ft copper grd rod for earth ground.
ANSWER: I solved the same problem by installing a low-pass filter right in back of the radio before feeding to the antenna. I think this filter cost me about $60.
For troublesome neighborhood TV's I used some inexpensive high pass filters.
Hope this takes care of it Scott.
Chris Bushman
WB6EEQ
North Hollywood, California
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QUESTION: Coincidentally, I happen to work for a major cable company as a line tech. High pass filters come cheap for me. A low-pass filter would basically trap out 50-1000mhz, which we also use, but its for 75 ohm cable. In your opinion, if done correctly, would it be possible to modify one of these for 50-ohm ham use without destroying my SWR's or causing an impedance mismatch?
Answer Yeah, Scott, you could design an impedance matching network for both sides of the filter, but it would introduce extra losses in the system.
Much better to shell out a few bucks and do it the easy, efficient way. I just checked HamRadioOutlet.com and they have low pass filters for $39.
