Ham Radio/Ham Radio CD-ROM (Emerald Software) (1995).ISO/news/inham89/1014

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INFO-HAMS Digest            Wed, 13 Dec 89       Volume 89 : Issue 1014

Today's Topics:
                               Antennas
                          Broadcast jammers
                Help Needed With Kenwood TH215 2M TCVR
                            Kenwood TS140
                         MAC logging program
                 Out-of-Band Tx/Rx Mods Reconsidered
                        Telephone Interference
                         WEFAX 105 Uploaded!!
----------------------------------------------------------------------

Date: 14 Dec 89 01:42:01 GMT
From: osu-20.ircc.ohio-state.edu![e-mail]  (Steve Bertsch)
Subject: Antennas
Message-ID: <[e-mail]>

In a few magazine articles I've seen the terms 'near field' and 'far field',
but I can't find any mention of these terms in any of the radio or
electronics texts I've tried. Can anyone define these terms?

------------------------------

Date: 12 Dec 89 13:45:47 GMT
From: mcsun!ukc!stc!datlog!torch![e-mail]  (Ian Phillipps)
Subject: Broadcast jammers
Message-ID: <[e-mail]>

[e-mail] (Alan Larson) writes:

(Refers to jamming on 7150kHz)
>As I recall, I had heard that most of the Soviet and Eastern European
>broadcast jamming stations had been shut down a few years ago.  I was...

>Does anyone know the status of these stations?

I heard that the BBC Mandarin service is being jammed by the Chinese.

------------------------------

Date: Wed, 13 Dec 89 17:00 CDT
From: "FEROZ GHOUSE, N9FJL/4S7FG" <[e-mail]>
Subject: Help Needed With Kenwood TH215 2M TCVR
Message-ID: <[e-mail]>

I am trying to use a Kenwood TH215 hand held TCVR as a start out rig on
packet radio. However, I am not able to get the PTT on it to work with
the external connections. I have followed the standard connections for
wiring the input to the external mic connector.

I have unfortunately misplaced my manual and right now am helpless!!
I would appreciate it if someone could give me the correct connections
so that I could connect to a TNC and packet away.

Thanks

Feroz Ghouse 4S7FG/N9FJL
<[e-mail]>

------------------------------

Date: 13 Dec 89 22:48:06 GMT
From: wind![e-mail]  (David H Copp)
Subject: Kenwood TS140
Message-ID: <[e-mail]>

I am considering purchasing a Kenwood TS140.  I would like to receive
opinions of the rig from people who have them.  TU es 73's
                David H. Copp  WS2I
                [phone]
                [e-mail]

------------------------------

Date: 13 Dec 89 17:34:45 GMT
From: att!cbnewsm![e-mail]  (JEFF ZELL NK3O)
Subject: MAC logging program
Message-ID: <[e-mail]>



    I am looking for a program for logging and printing of labels for QSL
cards.The machine of my choice is the Mac.There are very few program available
for the Mac.I have some shareware and PD programs but nothing that will do this
function
        TNX and 73
                JEFF NK3O

------------------------------

Date: 14 Dec 89 00:36:50 GMT
From: oliveb!orc!mipos3!cmdfs2![e-mail]  (James Bromley~)
Subject: Out-of-Band Tx/Rx Mods Reconsidered
Message-ID: <[e-mail]>

 Back in the good old days when transmitters consisted of
 self-excited oscillating fire bottles, staying on frequency (or
 just within a given band) was a real exercise in radio operator
 technical skill.  The usability of the medium was a direct
 function of this competency and, to protect the rights of all
 spectrum users, the principle of OPERATOR licensing in addition
 to STATION licensing was instituted by the U.S. and
 also through international conventions.

 Over the years, operator licensing became an institution in
 and of itself.  In the post-WWII Radio/TV heyday, a commercial
 (or even amateur) radio operator's license was a solid credential
 that led to a good technical job, sometimes only remotely
 connected to the actual transmission of a radio signal.  In
 amateur radio circles, with incentive licensing, higher degrees
 of operator competency were deemed very desirable and lavishly
 rewarded with wider operating frequency ranges.

 Today, off-frequency operation, whether it is the result of an
 unattenuated harmonic, excessive phase noise from a PLL, a
 spurious mixer product or (heaven forbid) dialing in the wrong
 frequency, can be even more of a problem in this ever more
 crowded medium.  Operator skill would seem to be at a premium
 to prevent interference and ensure orderly utilization of an
 admittedly limited resource.

 However, with the advent of radio equipment that is so
 technically sophisticated as to preclude almost all
 mis-operation (including off-frequency operation) the
 requirement for technically skilled operators decreases
 considerably. Consequently, the justification for imposing an
 OPERATOR licensing requirement with its concomitant tests for
 competency becomes much weaker.  Indeed, future licensing
 requirements might only be those for a STATION license.  And
 the criteria for granting such a license would be those
 currently used for broadcasting, land mobile, aeronautical,
 etc., namely demonstrable need, frequency congestion and
 integrity of the licensee.  No code, no theory, no legal
 knowledge....nothing.

 A strong argument for retaining operator licensing requirements
 would be the continuing use of radio equipment that was capable
 of interference-causing mis-operation.  Such equipment would
 necessarily have unrestricted frequency coverage (just like the
 old self-excited transmitters), have adjustments for modulation
 parameters and internal tuning readily accessible (ie: on the
 front panel) and be subject to a wide variety of modifications
 on its transmitter circuitry.  If high-powered, it would be capable
 of output far in excess of legal limits.  Only a highly skilled
 person could operate such equipment properly (and legally) and
 it would be in the clear interest of the United States to maintain
 the structure to license and regulate such operators.

 So the possession and use of modified radio equipment capable
 of out-of-band, excessively high powered operation may be the
 salvation of Amateur Radio as we know it, with LICENSED
 OPERATORS being required for station operation.  Otherwise,
 amateur radio could become just another
 land-mobile/point-to-point utility service.  Like Domino's
 Pizza or Joe's Plumbing.  Those people can't get off-frequency
 no matter what the (unlicensed) operator does.  Amateur Radio
 is a great deal woolier than that.  And the operator licenses
 that we all value dearly are testimony to the potentially
 illegal capability of our equipment and our skill in preventing
 such operation from occurring.

                                 de W5GYJ/7

------------------------------

Date: 13 Dec 89 20:28:30 GMT
From: cs.utexas.edu!helps!bongo![e-mail]  (julian macassey)
Subject: Telephone Interference
Message-ID: <[e-mail]>

In article <[e-mail]>, [e-mail] (alfred.a.schwarz..jr) writes:
>
>     Does anyone have any ideas/pointers on quieting down telephone
> interference?

    Below are some extracts from an article I wrote a couple of
years ago for Popular Communications Magazine. The Issue was Feb
1988, if you want to see the whole thing.


                        TELEPHONE INTERFERENCE

                        (CAUSES AND CURES)


      There  is some hope when it comes to interference. The  FCC
has  issued  a  field bulletin on RFI.  The  document  is  called
"Bulletin FO-10, Telephone Interference". Copies of it can be
obtained from any  FCC  field office.  Find  your nearest FCC
office by looking up FCC  in  the phone  book.  The  Bell
System has  considered  the  problem  and approach it from the
viewpoint of interference to regular 500 and 2500  type phone
sets. The Bell document concerning RFI is  known as  a  Bell
Systems Practice (BSP). The document is  BSP  Section
500-150-100.

      Before  you tear things apart and spend money, there are  a
few  things to check. These checks can be done with an  adjustable
wrench and a screwdriver. What is checked is anything on the line
itself  that could be acting as an antenna or detector.  A  dirty
connection can work as a diode to detect RF signals. Go over  the
internal wiring looking for the following:

 1.   Corroded connections. Clean and tighten.

 2.   Loose wire terminations, including set wiring and all jacks
and junction boxes. Tighten any loose screws.

 3.   Abandoned wire still connected to the line. Remove any wire
not connected to a working phone.

 4.    Old  unused devices still connected to  the  line.  Remove
abandoned phone answering machines, old telephones and bells etc.


     If  any of the above is what is causing the RFI,  until  you
fix  them,  there is little hope that anything else you  do  will
cure  the  problem.

      The  other  legal  "do it yourself" fix  is  attachment  of
toroid  cores.  These cores look like small black  doughnuts,  by
wrapping  wire round a ferrite core a simple effective RF  filter
or  choke can be made. Ferrite cores are frequency selective,  by
the choice of the right material, interference can be effectively
hit on the head.

          With  modern phones, the most RF sensitive part of  the
phone is the electret microphone and its preamplifier circuit. By
application of ferrite cores to the handset cord, there is a fair
chance  of  easily  and cheaply fixing the problem.  If  you  are
hearing radio signals on the phone, there is a way of checking if
the microphone/handset cord is to blame. Dial a partial number to
give you silence, listen for the interfering signals and grab the
handset  cord. If the signal changes in volume - gets  better  or
worse - try a ferrite core.

          The best source of ferrite cores in small quantities is
Amidon   Associates,  12033  Otsego  street,   North   Hollywood,
California  91607. PHONE: [phone]. Amidon Associates  have
several ferrite "mixes" available. For interference from 500  Khz
to  10  Mhz,  i.e.  AM broadcast RFI,  they  recommend  their  75
material. For interference from 1 to 30 Mhz they recommend  their
73  material. The 73 material should take care of all short  wave
Ham and CB interference. For low VHF and channel 2-7 RFI you  can
try  a ferrite core made with the 43 material which  should  take
care  of  RFI  between  1 and 70MHz. For  best  results  use  the
material  that has the lowest cutoff point for your  problem.  If
the local AM transmitter at 1070 KHz is your problem, use the  75
material, it will give much better attenuation at that  frequency
than the 73 material.

          For  a  handset cord, a half inch core is  ideal.  Wrap
four or five turns of the handset cord through the core and  plug
it  back  into the handset. The cord can be held  in  place  with
black  vinyl tape or glue, hot melt glue works  well.  Experiment
with  the positioning of the core. Often having the core  by  the
handset  works  best, other times plugging in the cord  with  the
core by the body of the phone is better. Sometimes a core at each
end  of  the cord is needed to do the trick. The cores  may  look
kinda clunky, but if they provide relief easily and cheaply,  who
are you to complain.

     The numbers for the half inch cores are: FT-50A-75,  FT-50A-
73  and FT-50A-43. Yes you guessed it - the last two digits  tell
you  the material being used. For one and a half inch cores  used
with line cords explained below, the numbers are: FT-140-75.  The
last two digits being the same as for the half inch cores.

          For  RFI that you suspect to be entering via the  phone
line, wrapping the line cord round a large core can help. Usually
it  is  best to place the core at the telephone end of  the  line
cord. Though like all RFI cures, experimentation, otherwise known
as "suck it and see", does a better job than hard and fast rules.
With  the  large core on the line cord, between  six  and  twenty
turns on the cord should do the trick. A core on each end of  the
line cord may help in stubborn cases.

          For   authorized  phone  repair   stations,   telephone
personnel and those willing to risk "Open circuit surgery", there
are several solutions. Using ferrite cores, twenty turns or so of
scrap  24 Gauge telephone wire can be wrapped round a  half  inch
ferrite  core.  Use two cores, one for Tip and one for  Ring  and
place them inside the phone. The same kind of cores and  windings
can   also  be  used,  inside  the  phone,  on  the   transmitter
(microphone) leads.

          For  those really handy with a smoking  soldering  iron
there  are  some  more fixes to try. For  phones  using  electret
microphones, some well placed capacitors may do the trick. Try  a
0.01 uF (10 NF) across the electret element. If that doesn't  work
try  the same value of cap across the hot side of the element  to
the  "ground"  of  the  pc  board.  Regular  phones  with  carbon
transmitters can be helped with a 0.01 or 0.1 uF capacitor across
the  element. Solder the capacitor across the contact fingers  in
the  handset,  not across the element, so if the  transmitter  is
changed,  the RF proofing will stay with the phone. Also,  inside
the  phone, a 0.1 uF (100 NF) 250V capacitor across Tip and  Ring
can  be  helpful. The type of capacitor to use is  a  Ceramic  or
Mylar.

          For those with access to AT&T parts or wishing to  help
the  local phone company, there are a couple of bits  of  helpful
hardware  mentioned in Bell Systems Practice  500-150-100.  First
there is a coil that should be spliced into the phone line. It is
called  a 1542A inductor. It should be spliced into the  line  as
near  as the offending telephone set as possible. This means  put
it  right before the modular jack. It has six terminals, two  for
Tip,  two  for Ring and two for a ground, should the  phone  still
need  a  ground (yellow wire) for the ringer or party  line.  The
ground  terminals  are not in any way connected to the  coil,  so
bringing  a ground to the inductor, unless needed in  the  phone,
will not help cure any RFI.

          The Bell document also mentions a capacitor, designated
a 40BA capacitor. It is actually four capacitors (see Fig 1)  and
the intent is to place a capacitor between each leg of the  phone
line  and ground. The 40BA is usually installed at the  telephone
protector.  There  is  always  a good  ground  available  at  the
protector,  often a heavy gauge solid, solid gray jacketed  wire.
Those  telephone  personnel  who do not have  access  to  a  40BA
capacitor  should  find  that  a couple  of  0.1  uF  250V  Mylar
capacitors  will  work just as well (see Fig 2). To  install  the
40BA  or 0.1uF capacitors, find the protector. The  protector  is
usually outside the building in a wall mounted small box, in  the
basement  or in a closet for businesses and apartment  buildings.
If the phone line comes in on overhead cable, the protector  will
be  in  the  first  box the cable  goes  to  after  entering  the
premises.

          That should be some help in beating the problem.  Don't
forget that some types of phones are more sensitive than  others.
Some  cases may be so severe that nothing helps. AT&T  no  longer
have  RFI  proofed phones available, although an old  style  desk
phone  with some capacitors added will be pretty immune  to  RFI.
Alas  AT&T  no  longer makes old style 500 and  2500  desk  sets,
although they sell reconditioned ones. Several manufacturers such
as  ITT,  Comdial,  and Northern Telecom  still  make  old  style
phones.

                            END

This article appeared on Page 56 of the Feb 1988 edition of
Popular Communications Magazine.


Fig 1>
        250nF 250nF     250nF 250nF
 TIP O---| |--| |----O----| |--| |---O RING
             |
             |
            ---
             -

AT&T 40BA capacitor schematic and connection diagram

Fig 2>

        100nF            100nF
 TIP O----| |--------O-----| |--------O Ring
                     |
                     |
                    ---
                     -
Schematic for 100 nF capacitors on telephone protector.

Hope this helps.

--
Julian Macassey, n6are  [e-mail]  {ucla-an!denwa!bongo!julian
N6ARE@K6IYK (Packet Radio) n6are.ampr.org [44.16.0.81] voice [phone]

------------------------------

Date: 13 Dec 89 16:30:28 GMT
From: att!cbnewsj![e-mail]  (john.ferro..jr)
Subject: WEFAX 105 Uploaded!!
Message-ID: <[e-mail]>

In article <[e-mail]>, [e-mail] (Mike Storke (N7MSD)) writes:


Mike,
Could you please send me a copy of WEFAX 105. Would this get to me
through E-mail?

Thanks john Ferro

------------------------------

End of INFO-HAMS Digest V89 Issue #1014
***************************************