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Text File | 1994-04-03 | 10KB | 168 lines

                                RAIN FOCUS
                            by Hap Holly/KC9RP

        From Telephone to Tape

        How often have you tuned into your local info net only to find that
 when it came time to transmit Newsline or the RAIN Dialup, the recording
 made from the phone line resembled that of an old Victrola or worse yet a
 string with a tin can attached to either end?  In this age of digital
 audio, there is no excuse for this.  Ken Piletic/W9ZMR of Streamwood, IL
 has maintained the Chicago area Newsline telephone service since the early
 1980's.  He has some ideas as to what sounds good, and what doesn't.  The
 following was adapted from his presentation heard in January during the
 RAIN Dialup Service (708-827-RAIN).

        "A lot of people use the microphone-to-earpiece method of getting
 audio from the phone.  That's where you stick your tape recorder microphone
 by the telephone handset ear piece.  It doesn't work very well.  Among
 other things, you have to be concerned about keeping room noise out.  One
 way is to put the microphone and handset on top of a pillow and put another
 pillow on top of them.  In a pinch, that may be the only way you can do it.
 However, the audio quality isn't good because you're limited to the
 frequencies that come out of the ear piece.  There are other much more
 effective methods for getting good audio from the telephone to the tape
 recorder."


        THE SUCTION CUP METHOD

        "The suction cup is basically a pickup coil that can be bought at
 Radio Shack (part number 44533) for $3.99.  It's nothing but a coil built
 into a little plastic housing with a suction cup on the end of it.  You can
 put this device often in one of 2 places.  Your older telephone has a big
 transformer in the base.  You can move the suction cup around the base,
 listening at the same time for the loudest signal, at which time you simply
 push the cup a little harder, causing it to stick.  If that doesn't work,
 move the suction cup around the back side of the ear piece."

        "The advantage of using a suction cup device is you don't have to
 make any physical connection to the telephone.  It's a good way to go if
 you have right environment for it.  However, there are 2 disadvantages.  If
 you attach the cup on the handset, any room noise will be picked up by the
 handset's microphone.  On older phones, you could unscrew the mouth piece
 and remove the microphone element, thereby that problem.  You won't have
 that problem if you attach it somewhere on the base instead.  The other
 problem is that the suction cup device is actually an inductive coil.  AC
 transformers in your shack putting out some kind of magnetic field can
 generate hum, depending upon where the telephone or suction cup is
 positioned.  You may have to move one or the other around to hopefully
 minimize that."


        CLIPS TO TERMINALS

        "As mentioned earlier, your older telephone has a mouth piece that
 can be removed, as well as an ear piece.  If you unscrew the ear piece,
 you'll find 2 wires that are used to make the ear phone work.  With a
 patch cable that has alligator clips on one end and a mini plug on the
 other, (Radio Shack part number 422421 for $2.39), attach the clips to the
 2 wires, and plug the other end into your cassette recorder."


        WHICH INPUT TO PUT IN

        "Most cassette recorders have 2 inputs, one is the microphone jack,
 the other a high level input typically labeled line in or auxiliary.
 Whenever plugging something directly into the tape recorder, you should
 use the high level input because what you're plugging in is usually high
 level.  Otherwise you will encounter distorted recordings if the microphone
 input is used.  It won't matter which of the 2 wires you use from the
 telephone handset earpiece, polarity is not an issue, since neither wire
 from the handset ear piece is grounded.  In some cases one might have less
 hum than the other.  If your cassette machine doesn't have a high level
 input, then you have to attenuate, or lower, the audio level from the
 telephone to avoid overloading the microphone input.  Another trip through
 the Radio Shack catalog will reveal 3 attenuator options: a one-piece
 female RCA/phono plug to male mini plug attenuator (part number 274300 for
 $2.99), a cable with male RCA/phono on one end and a male mini on the other
 (part number 422461 for $3.99), and a cable with a mini male on both ends
 (part number 422152 for $3.49).  If you're going to use the clips to
 terminals method for getting audio from your phone to your cassette
 machine, simply snip the plug off one end of an attenuator cable, and
 attach an alligator clip to the 2 wires."


        CLIPS TO MODULAR

        "What if you happen to have a telephone handset that won't allow you
 to unscrew either the mouth or ear piece?  Well fortunately contemporary
 telephones have modular plugs (sockets) on both the base and handset.
 When you disconnect the modular cable, you'll notice the socket has four
 wires in it.  With the keyway on the top, the little wires lining the
 bottom of the socket should be equivalent to the following from left to
 right: red on the left; the next would be white; the next would be green;
 and the righthand one would be black.  Two of those go to the microphone
 element, the other 2 to the earphone.  We're interested in the second wire
 from the left, and the right most one regardless of what colors then are.
 You can get to these connections by using a modular cable, or another
 socket.  I can unplug the modular cable from my telephone handset, and plug
 it into a socket I found at a local hamfest identical to that found in your
 typical handset.  I soldered one end of my audio cable to the appropriate
 wires in the socket.  The other end of course goes into my tape recorder.
 Patching into your telephone by this method does not load down any audio
 circuits, and will work with your typical modern-day telephone.  The other
 obvious advantage is that when you eliminate the handset from the circuit,
 you don't have to worry about picking up ANY room noise.  Remember you'll
 need to take the handset off the cradle for this method to work."


        PHONE PATCH OR QKT

        "If you've run phone patches from a low-band station, you probably
 know you can get a phone patch unit from most manufacturers of ham
 transceivers.  I won't go into how to connect the phone patch here, but if
 you have a patch you can take audio from it into your tape recorder."

        "The telephone company used to, and may still, provide something
 called a QKT.  The QKT is made for running audio into the phone line, while
 at the same time protecting the circuit so you don't overload the local
 telephone switching equipment.  However, the QKT can also be used to take
 audio OFF the phone line.  That's the way I do it most of the time when
 I'm at home.  I use a QKT the local phone company provided me some years
 ago.  It's a little box that attaches to the wall and has a high level
 output.  I plug one end of my audio cable into it, and plug the other end
 into the line level input of my tape recorder.  You may have to use an
 attenuator chord if you have to use the microphone input.  As far as I
 know, the QKT is something that the broadcast industry still uses primarily
 to protect the phone company equipment, rather than to take audio from it.
 I have seen these units occasionally at hamfests."


        TRANSFORMER OR REPEATER COIL

        "The telephone company used to have a device called a repeater coil,
 which was a 600-ohm transformer with more than one winding.  The one that I
 have has the primary winding plus 3 secondaries.  I can put the primary
 winding directly across the phone line itself.  Assuming there is no
 conversation on the line at the time, the transformer will seize the line
 as soon as it is connected, giving me a dial tone.  In other words, I have
 to place the call first, then connect the transformer.  Any one of the 3
 secondaries can be used for recording purposes.  As that secondary will
 have an impedance of 600 ohms, you may not be able to plug it directly into
 the microphone input.  You'll probably need to run the audio through some
 kind of attenuator circuit because the volume will be too loud otherwise.
 I don't recommend you use a transformer because when you're using one,
 you're going directly across the phone line, which can result in problems
 with the phone company.  However, this is another way of getting audio
 from your telephone to your tape recorder."

        Editorial Note: In addition to the suggestions expressed above,
 Radio Shack has several devices called telephone controllers in the $20
 to $40 range that may be worth considering.

        If you're making plans to attend the Dayton Hamvention in Dayton,
 Ohio, the weekend of April 29th, drop by the RAIN/This Week in Amateur
 Radio booth between forum rooms 1 and 2.  In addition, Hap Holly/KC9RP,
 RAIN's producer and founder, will be one of a number of speakers scheduled
 to participate in a forum tentatively titled, "Ham Radio News and Views
 Worldwide" scheduled Saturday afternoon from 2:45 to 5:00 o'clock.  It
 will include live and video taped presentations from New Zealand, Radio
 Society of Great Britain, and South Africa, plus domestic services:
 Ham Radio and More, Spectrum, This Week in Amateur Radio, Amateur Radio
 Newsline, and, of course, RAIN.  The forum is being organized by Hap and
 Newsline producer, Bill Pasternak/WA6ITF.

     Please note that the RAIN Dialup's new phone number is 708-827-RAIN.