Interference Problems


	 So you got that new modem and are now hooked up to the BBS. What
    is	all this garbage being printed on the screen??? You say I've hooked
    up the modem correctly and have the terminal program set for the modem.
    NOW WHAT'S WRONG???? Well friend you may have just been bitten by the
    phone line or computer noise bug. When it bites it does a job on you
    (or should I say your computer). Here are a few hints that may ease the
    bite. Be aware that it is doubtful that you can cure all of it. Ma Bell
    has tried to for years!

	 Let's take a look at what line or computer noise is and then maybe
    we can knock it down to a bearable level.

	 Computer noise:

	 Computer noise comes from a great many places inside the computer
    itself. The chips themselves make a certain amount of it. The crystal
    which gives us the timing for the clock, the disk drive and causes all
    the instructions you or the program give it to move through the
    computer correctly generates a great deal of noise. The FCC (Federal
    Communications Commission) sets a limit on how much noise
    (interference) is allowable. It is a pretty high allowable limit for
    home use computers and lower for commercial or heavy use computers.

	 Here is something to try. Turn on your computer and all other
    hooked up equipment. Then bring in a TV or an AM/FM radio. Turn on the
    radio or TV and tune through the channels or band. You will soon hear
    on certain channels or frequencies a lot of strange sounding noise. If
    you begin to turn off your computer equipment the noise will change or
    go away. This can and many times is part of the problem. This should be
    cleaned up as much as possible before doing anything else. Be aware
    that you probably won't get rid of all of it, but you should be able to
    knock it down. Let's see what can be done without getting into the
    computer.

	 First be sure you are putting your AC plug into a 3 wire
    receptacle that has all three wires hooked up!!! You think this guy is
    crazy right?? Wrong!! Many times it looks as if you have three wires
    but---get an AC line checker and make sure. Then get a line protector
    which protects against spikes and noise. Radio Shack sells them and so
    do many other places. ACE Hardware in Altus is one. You can buy them
    from advertisers in many of the magazines. By the way, everytime you
    change something check the radio or TV to see if the noise you heard
    has changed. Don't get discouraged. Sometimes you will have to do
    several things to see a difference.

	 Next get a length of wire and ground ALL of your equipment
    together. That means to hook the wire to your compute where there is
    metal showing, then to the modem, the printer, vidio terminal, etc.
    Make sure you have metal to metal contact. Again check the radio or TV
    to see if the noise has dropped. You can also check to see if the BBS
    looks better on your terminal.

	 Now let's try to erase some of noise that can be coming from your
    AC power cords. Radio Shack has toroid choke cores (part # 273-104) two
    to a package for about $7.00. No I don't work for them. They are
    available at the store here, thank goodness. Follow the instructions on
    the package and put them on each AC power cord.

	 When you have done all this you have done about all you can do
    without getting into the computer or printer. I hope this will help
    solve some of the problem.


			    Telephone Line Problems

	 Well you tried all that stuff about the AC line and you still have
    problems!! That Blankety Blank guy still hasn't cured MY problem!! I
    never said it would be easy and I never said ALL of it could be cured.
    Here are some tips on the phone line itself that could cure or at least
    knock down the problem.

	 Do you have a cordless telephone?? If you do is it turned on
    and/or hooked up? If it is turn it off and unhook it (YES BOTH) and try
    the BBS again. The GE cordless with PLL that was sold at Altus AFB WILL
    cause problems. I'll sell one cheap!!

	 Do you have only one phone number in your house? I don't care how
    many phones, just the numbers. Be aware that the phone company brings
    in 4 wires, but only two plus a ground  are used for a single phone
    number. AHA-trouble right? Right! The unused line can act as an antenna
    and pick up noise or RFI (radio frequency interference). Can this be
    cured? Yes to a certain degree. How? Well here we go----.

	 Telephone wire can break down from age, temperature extreems (we
    sure have that here) and from movement (twisting, being hit, going
    through walls, +++). The best thing to do is to instal new wire to
    where you will use the modem and NOT have any phone on that line. You
    can buy installation kits almost anywhere and it is very easy to do it
    yourself. One thing, never use staples to mount the wire to the wall as
    you run it to the modem. They can break the wire. There is a plastic
    clip (KMart and WalMart sells it) with a nail at one end. This is a
    much better way and will cause less problems. When you hook up the wire
    to the phone block outside the house be sure you remember which wire is
    ground. It's marked. You may want to use it later.

	 If you do the above or decide your wire is ok then you may want to
    try this. Turn on your computer and modem plus all other items you want
    on. Then while in terminal mode type AT M2 L . M2 should keep your
    speaker on all the time and L should set the volume to low so you can
    stand the noise. Now access the BBS and watch the terminal and listen
    for popping noise. If you hear noise (besides the normal sound the
    modem makes) you should see garbage printed out at the same time. If
    you see the garbage or hear noise then shut down, use AT M1 to reset
    the speaker to default. Then go outside to the phone box. Check what
    wires are being used. In my case the red and green were, with yellow as
    ground. The black wire coming into the house was not even connected.
    Strip a little of the plastic from the wire that is not being used and
    connect it to ground. Then check the modem as before. Less popping and
    less garbage?? I hope so. If not try this as just about the last
    resort. Go to Radio Shack and get two small ceramic capacitors. The
    value should be .001 (272-126) to .0047 (272-130). These should work
    with no problem. Now remove the cover on the connector block where your
    modem is connected to the phone lines. Connect one wire on each
    capacitor to each of the wires that are in use (the ones you checked on
    the outside box). Connect the other wire on the capacitor to  the
    ground wire connection. In my case I connected a capacitor between red
    and yellow, then another between green and yellow. Replace the cover
    and try the BBS again. Gets tiring doesn't it?? The only other thing
    you can try is to use a toroid choke core on the phone line going to
    the modem. Do it the same way as you did the AC cords.

	 This is about all you can do to your equipment and SHOULD cure
    most of the problem. I sure hope it does!!!

	 There are two other items I use on the phone line, a ringer
    silencer (RS #43-127) $7.95 and a spike protector (RS #43-102) $12.95.
    These are not really needed but they are sure nice to have.

	 If you have a question on interference I'll try to answer it for
    you. Please understand that I am not an expert. I'm just a ham radio
    operator who like computers and has had problems with interference.

						      GOOD LUCK

						     Robert L. Willsey
						     Box 10
						     Martha, OK 73556

							  OR
						      BobWill (#27)
						      Majik Shoppee
						      405-482-2536