🚀 go-pugleaf

In article <4502@feldspar2.UUCP> svec@motcid.UUCP (Larry Svec) writes:
+Another alternative if you don't want to drill a hole is I have seen
+in various 'add on junk to cars' catalogs, a duplexer or matching box
+that allows you to use your AM/FM Broadcast antenna on CB (27Mhz)
+Don't know how it works (or doesn't) but I recall it being about 10 or 15
+bucks...
+-- 

 Take some advice from someone that tried all  these,  THEY'RE  JUNK!  The
thru-glass  antennas (Avanti) work marginally at 2m.  For 450MHz they will
reduce the useful bandwidth to about 1/2 MHz, but don't  try  to  run  any
power!  About  10  watts  RMS  is maximum...otherwise the coupler-box gets
real sick and blows a coil/cap.

 The AM Broadcast Band/11 meter CB diplexers are even  worse!  They  won't
take  more than 7 or 8 watts, the radiation pattern sucks and when you try
to use them with an in-glass AM/FM radio antenna you run the  risk  frying
your  expensive in-the-windshield antenna!  The auto manufacturers *never*
intended that these be  used  for  transmitting..hence  the  size  of  the
conductor  is  quite  small  and will not withstand the current loading of
even a modern 2-4 watt mini-CB unit!

 These antennas are simply a MONEY_MAKER for the manufacturers! They are
terrible performers compared to a real antenna!


 If you want a good radiation pattern, power handling capability, the best
in  receive  signal  strength; buy a ball and spring mount and use it with
either a stainless steel 102" whip or a Hustler fold-over,  54"  mast  and
the  proper  11 meter resonator coil & tip.  Mount it as high and as close
to the center of the vehicle as possible.  If you are worried about theft,
you  can  add a quick disconnect to make removal and installation easy.  I
would also recommend that you *AVOID* rg-58u coax!  It's  lossy,  it  dies
quickly  in  the  UV of sunlight, and it won't handle any real power. - Go
with either rg-213, if you've got the space to use it, or the newer mini-8
(which  is  the  same  size as rg-58u, but has better specs) if space is a
problem.

 If your scenario dictates concealing the use of a transmitter, my  honest
recommendation  is to use some piano-wire and clear vinyl strapping tape..
..apply it to either the upper or lower width of the  windshield  or  rear
window,  having  first  soldiered  a  piece  of  mini-8  (via  the  center
conductor!) to it.  Stay clear of  the  window  defroster/defogger  heater
wires!  The  braid or outer shield is run to ground via the shortest route
possible.  Put a PL259 plug on the end of the coax.  Then get  an  antenna
tuner  box.  These can be as costly as you wish or can be made up from the
circuits found in any edition of the ARRL handbook,  nominally  for  under
$20.
     <-----------wide as possible!--------------->
      ===========================================    braid
      ------1/16" piano wire--------------------|-- ...............
      =========================================== |               |
						  |center wire    grnd
Transceiver <-> Tuner<->SWR meter< ---------------


 Coax between the units now, no funny stuff! And watch those soldier joints!


 Tune the tuner for the lowest reflected power, and the highest forward power.


 We did some of these for our local Police a few years back...worked great
but it takes some time and effort to setup and tune, plus it's not exactly
an off the shelf item.  It will work better than anything you CAN  buy  in
the  shops  though, and it will handle the power without trouble...too bad
you can't run more than 5 watts on CB...(wink!)..if you could,  you  would
put the amp between your radio and the tuner...for instance, if you were a
LICENSED AMATEUR, and you wanted to use this setup for 10 meters...be sure
to use good quality coax for all the jumpers, at least mini-8.

 And as a parting shot, why bother with CB??  You can easily get your  ham
ticket  by  passing  a  simple  written  test of 30 questions, the pool of
questions is a published work!  There is also a  5  WPM  Morse  code  exam
which  can be easily learned from tapes whilst driving..there are probably
a number of Amateur radio clubs in *your* area that offer classes and help
with studying for the exams!  Enjoy!


-Avatar-> (aka: Erik K. Sorgatz) KB6LUY           +-------------------------+
Citicorp(+)TTI                          *----------> panic trap; type = N+1 *
3100 Ocean Park Blvd. Santa Monica, CA  90405     +-------------------------+
{csun,philabs,psivax,pyramid,quad1,rdlvax,retix}!ttidca!sorgatz **
(OPINIONS EXPRESSED DO NOT REFLECT THE VIEWS OF CITICORP OR ITS MANAGEMENT!)