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#1
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Hello dear all !
I am using R-7000 vertical located on the roof of 9-store building. I was happy to notice the absence of any QRM for both radio and TV broadcasting with my new 1 KW amplifier. But there is the only problem with neighbor from the last floor - he can hear some SSB transmission in his phone and It slows down or even breaks the dial up connection to Internet. Are there any links for ready or homebrew RF filter for "last mile" of phone line? Any suggestion for this case? Is it possible to ovecome this problem at all ? Regards, 73 de UR5EOA Igor |
#2
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On Sun, 11 Jan 2004 22:01:43 +0200, "Igor V. Lapko"
wrote: Hello dear all ! I am using R-7000 vertical located on the roof of 9-store building. I was happy to notice the absence of any QRM for both radio and TV broadcasting with my new 1 KW amplifier. But there is the only problem with neighbor from the last floor - he can hear some SSB transmission in his phone and It slows down or even breaks the dial up connection to Internet. Are there any links for ready or homebrew RF filter for "last mile" of phone line? Any suggestion for this case? Hi Igor, As a neighborly gesture, offer him ferrite clip on (split toroid, ferrite cores) to go around the power leads and the telephone leads. Search for "Amidon" or "Fair-rite" components and engineering documentation. You should be able to find equivalent sources near you. 73's Richard Clark, KB7QHC |
#3
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Hi Igor,
I just want to confirm that the split ferrites on the phone line at the input to the phone should clear up most phone interference. If it persists then add the core to the power leads again at the input to the phone. For the internet connection, use the same. Ferrites on the phone line right at the computer. And, if needed, the core on the power leads for the computer. I use both at the KW level and the ferrites stop the interference 100%. Deacon Dave, W1MCE + + + Igor V. Lapko wrote: Hello dear all ! SNIP But there is the only problem with neighbor from the last floor - he can hear some SSB transmission in his phone and It slows down or even breaks the dial up connection to Internet. SNIP |
#4
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Igor,
If all else fails, try this: As close to the phone as possible, put a ~56 Ohm resistor in series with each side of the telephone line. Then connect a ..01 ufd 300V capacitor across the line on the telephone side of the resistors. The capacitor has to be high voltage, because during ringing, the voltage can be around 200 Volts. Tam/WB2TT "Igor V. Lapko" wrote in message ... Hello dear all ! I am using R-7000 vertical located on the roof of 9-store building. I was happy to notice the absence of any QRM for both radio and TV broadcasting with my new 1 KW amplifier. But there is the only problem with neighbor from the last floor - he can hear some SSB transmission in his phone and It slows down or even breaks the dial up connection to Internet. Are there any links for ready or homebrew RF filter for "last mile" of phone line? Any suggestion for this case? Is it possible to ovecome this problem at all ? Regards, 73 de UR5EOA Igor |
#5
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At the 2003 ARRL Southwestern Division Conference, Steve Jensen, W6RHM,
gave a very informative presentation titled "EMC for the Ham Shack". Steve's paper described how RF could easily be induced into a shack's AC power line. He also provided a relatively simple easy solution. Steve suggested using Fair-rite 5943003801 cores. These are relatively large cores. An AC power plug will fit through them. One core should be on the coax line near the antenna. Another core should be placed on the AC power cord of your power supply. This should minimize inducing RF into the building's AC system. A supplier of Fair-rite cores is Loadstone Pacific http://www.loadstonepacific.com/. The price per core is under $5. They do have a $50 minimum per order. Duane Allen, N6JPO Igor V. Lapko wrote: I am using R-7000 vertical located on the roof of 9-store building. I was happy to notice the absence of any QRM for both radio and TV broadcasting with my new 1 KW amplifier. But there is the only problem with neighbor from the last floor - he can hear some SSB transmission in his phone and It slows down or even breaks the dial up connection to Internet. Are there any links for ready or homebrew RF filter for "last mile" of phone line? Any suggestion for this case? Is it possible to ovecome this problem at all ? Regards, 73 de UR5EOA Igor |
#6
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On Mon, 12 Jan 2004 17:44:05 GMT, Duane Allen
wrote: A supplier of Fair-rite cores is Loadstone Pacific http://www.loadstonepacific.com/. The price per core is under $5. They do have a $50 minimum per order. Try http://www.lodestonepacific.com/ -- the one supplied does not resolve. |
#8
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Igor ... after watching some of the replies ..
Igor V. Lapko wrote: Hello dear all ! I am using R-7000 vertical located on the roof of 9-store building. I was happy to notice the absence of any QRM for both radio and TV broadcasting with my new 1 KW amplifier. But there is the only problem with neighbor from the last floor - he can hear some SSB transmission in his phone and It slows down or even breaks the dial up connection to Internet. Are there any links for ready or homebrew RF filter for "last mile" of phone line? Any suggestion for this case? Is it possible to ovecome this problem at all ? Regards, 73 de UR5EOA Igor The simplest cheapest place in the USA I have found to buy these little ferrite core gadgets you can loop coax and speaker leads and power leads around .. is at Radio Shack. You can buy packages of several for a few USD. They have a little plastic holder that splits them apart so that you can open the ring core and wrape a line around them without cutting anything. I've been using them all around the place for years on phone lines, speaker lines. coax lines to country TV andtenna problems and so on. No, they are not good enough for everything. But they sure make it easy to test things for improvements and help you figure out where a problem may be solved. -- -- Sleep well; OS2's still awake! ![]() Mike Luther |
#9
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wrote:
On Mon, 12 Jan 2004 17:44:05 GMT, Duane Allen wrote: A supplier of Fair-rite cores is Loadstone Pacific http://www.loadstonepacific.com/. The price per core is under $5. They do have a $50 minimum per order. Try http://www.lodestonepacific.com/ -- the one supplied does not resolve. You are correct. It is lodestonepacific. Thanks for the correction. |
#10
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Thanks Ian, and for emphasis on the point!
Ian White, G3SEK wrote: Ferrite isn't magic, so don't expect one small clip-on ferrite core to solve all your RFI problems. There are some RFI cases where a single clip-on core is a complete cure... but there are many more cases where it's not enough. To have some serious chance of curing RFI, you need to use several turns on a fairly large lump of ferrite. Note the recommendation about the Fair-rite 5943003801 core. This is a large core, of the right grade (#43) for good HF performance, and also you need to wind several turns of the phone line through it. A choke like that will be equivalent to a string of maybe 20-30 clip-on cores... so if one clip-on core doesn't work, try harder. My point was that if you could notice a change in the problem for the better, you have a path down which to go. Doing a better job of solving the problem is better than never finding which road has problems on it. -- -- Sleep well; OS2's still awake! ![]() Mike Luther |