R7000.20
Part 1/2
                      A LOW COST PANADAPTOR
                         FOR THE R-7000

                      by Bob Parnass, AJ9S

     A panadaptor, or spectrum display, is  a  device  which
     portrays  visually  the  signals in a part of the radio
     spectrum.  Panadaptors allow radio listeners  to  "see"
     activity  on  a  portion  of band without requiring the
     listener to tune the receiver.

     They are useful for detecting the  presence  of  spread
     spectrum  signals  or "hidden" signals riding on a sub-
     carrier of a main channel.  Panadaptors are  invaluable
     for detecting spurious emissions from transmitters, and
     unwanted products caused when 2 or more signals mix.

     Panadaptors most often employ a cathode ray tube  (CRT)
     for  the  display,  and must be connected to the inter-
     mediate frequency (IF) amplifier stage of  a  receiver,
     at a point before filtering takes place.

     The ICOM R-7000 2-2000 MHz receiver rear  panel  has  a
     phono jack for wide band 10.7 MHz IF output.  A DC vol-
     tage is also present at this connector and is  used  to
     power an ICOM TV accessory.

     I've seen mention of 3 panadaptors for the R7000:

       1.  John Biro's article on  retuning  a  Yaesu  YO901
           Multiscope  panadaptor  for  10.7 MHz, restricted
           bandwidth use.  Selectable bandwidths of 20, 100,
           or 200 KHz are available.

       2.  The Sherwood Communications SCA-7000 signal moni-
           tor,  priced  at  $1600, and reviewed in May 1987
           "Monitoring Times".3 Bandwidth adjustable from  1
           KHz - 1 MHz.

       3.  The  Spectra-Display,  priced  at   $350,   which
           requires use of  an  external  scope.4  Bandwidth
           adjustable from  200  KHz  -  10  MHz.   Optional
           preamplifier required for 12 MHz wide sweep.

CONTINUED IN R7000.21