QRM for Internet
 

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

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

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

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

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

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.

On Mon, 12 Jan 2004 22:49:40 GMT, 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.

Spelling is so important.

Lodestone would make more sense when discussing magnets.

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

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

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.

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

"Ian White, G3SEK" wrote in message
...

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.

Also, note that the simple ferrite fix only works for common mode RF.
Anything that is differential will get rectified and detected. The phone
line could be unbalanced at RF, even though it is balanced at audio. The
only way to supress differential RF is to filter each lead separately.

The reason for the rectification is that they tend to put a bridge rectifier
at the line input. This way the phone still works if the tip/ring polarity
of the 48V has been switched.

Tam/WB2TT