Managing 6m Interference Click here to go back to the home page

Mike, KS0F -

First let me say its sunshine, blue skies and about 70 degrees with a mild sw breeze here in EM48 near St. Louis. All problems look much better with wx like this. Even interference! Number One..............Do everything possible to maintain a dialog with the party/parties in question.

OK now you are talking to the neighbor and you know what the problem is and you know your station is clean. Right? Not sure? Do 1 through 6 again.

Understand that you need to make your time with the neighbor as minimal as possible. If you go wasting a lot of his/her time in helter skelter tests etc you are going to make the situation worse. The neighbor just wants it fixed and doesn't want to be bothered by you or know anything about your radio or the law or the rules and regs and the manufactures fault in equipment design. He does not care. He is not going to care and you cannot make him care. Remember that.

Now your are ready to get to work. Beg, Borrow or Buy a copy of the book from ARRL called Radio Frequency Interference How to find it and how to fix it. I bought several interference books in the last year and I like this one best. You can address specific types of interference rather quickly without going into great detail about cause and effect. Although the book does go into those details it is laid out better as a working manual than the others I have seen. Page through the book and get a feel for the layout. Look up the sections on your specific problem/s and read through them. Take a little time and get comfortable with the book.

TV interference. There are two differant situations here. Strong ch2 signal areas and weak ones. Regardless of the location the first thing that has to be done is the TV installation checkout. You have to get the neighbor to allow you to look at his installation. Common sense will determine possible problem areas in his installation. A lot of advise has been written about doing work on a neighbors stuff and it really is a judgement call for the ham to make. What do you want to do, how bad to you want to maintain a good relationship with the neighbor etc. Every situation and person and ham is quite different. You will have to factor this out yourself. The following is an example only but is real world. I have been having a very bad time with a neighbor across the street from me with TVI. He just bought a cordless phone too last year. 6 meters was the main problem even though we are in a strong signal area for TV.

Obviously I was getting into his cordless too. It made no difference what band or power I was using or what channel the neighbor was on. I would absolutely wipe him out. Even low power 5 watts on 2 FM killed his TV. Enlisting a couple hams to do a check out and verify I was able to find out the above with their help. They looked over the system at the neighbors and made a determination. His feed system on his outside antenna was the main suspect. He had old style twin lead from an outside yagi to his basement. In his basement he twisted two runs of twin lead together on the lead from the outside antenna. Each went to a vcr/tv combination with one having a pair of rabbit ears attached also. A month later at my request and the consent of the neighbor WA0KBZ ran new RG6 from the antenna to a proper splitter in the basement and RG6 from there to the two vcrs. Nothing else was done.........Nothing else was done. KE0FV came in on the tail of the install by Bill and He and Bill finished up and ran the tests. Would you believe that there was no interference at all anywhere on any channel on any band at all the power I could muster with the antennas pointed right down his throat? Would you believe that? You should. The only problem was one vcr picked up 500 watts of 2 meters when the antenna was pointed directly at him. With the antenna off 15 degrees or more it was gone. This was only on one vcr. The neighbors wife was so happy with her new tv reception which was about a gozillion percent better than what she had ever had that Bill and Keith left there heros. I found 900mhz conventional cordless phones on sale locally here for 99 bux. I bought 3 of them. I loaned one to the above neighbor and the neighbor next door to me and kept one myself. No six meter Interference to these Tropez phones at all on 6 meters. My next instalment will talk about the neighbor next door to me who is on cable.

I will get into many subjects from a real world standpoint on the subject in subsequent installments of this breath taking cliff hanging serial. So please do not be disappointed if I do not address your own problem right off. However I do promise to include information on 6 meters and 49Mhz cordless in peaceful coexistence.

BTW before I forget and get any further let me be redundant. I have many times hawked the wonders and magic done by the install of a handbook stripline filter in the 6 meter station. Check it out. This is a passive device and simple mechanical construction. I wouldn't get on 6 without one. I strongly recommend you look into building one if you are going to operate on 6 whether you have interference problems or not.

73, Mike KS0F

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