Review: Radio Shack PRO-2035 vs. PRO-2006 scanner

Review: Radio Shack PRO-2035 vs. PRO-2006 scanner

Post by Bob Parnass, AJ » Mon, 01 May 1995 04:00:00

              The Radio Shack PRO-2035 Scanner:
           How Does It Compare With the PRO-2006?

          Copyright 1994, 1995 by Bob Parnass, AJ9S

  [NOTES: An earlier version of this article  was  published
 in  the author's Scanner Equipment column, Monitoring Times
 magazine, January 1995.  This article may not be reproduced
 in  whole  or  in  part  on  CDROMS,  in  bulletin  boards,
 networks, or publications which charge for service  without
 permission of the author.]

        Radio  Shack  recently  discontinued  the  PRO-2006,
 perhaps  the  best base/mobile scanner radio ever sold, and
 replaced it with the  1000  channel  PRO-2035.   Bob  Grove
 reviewed  the  PRO-2035  in  October  1994 Monitoring Times
 magazine.  How does it stack up against the PRO-2006?  Read


        In 1986, Radio Shack introduced  the  PRO-2004  wide
 band  programmable  scanner and it immediately captured the
 attention of hobbyists.  The PRO-2004 was made  by  General
 Research Electronics and was different from other models of
 that era due to its large 300 channel capacity  and  nearly
 continuous  frequency  coverage  of 25 to 1300 MHz.  Key to
 the  PRO-2004's  superior  performance  over  such  a  wide
 frequency  range  was  the use of "up conversion," a design
 found in expensive commercial and military receivers.
        The PRO-2004 was replaced by the PRO-2005  in  1989,
 which  was  upgraded  to  the PRO-2006 one year later.  The
 PRO-2005 and PRO-2006 were manufactured using tiny  surface
 mount  components, and despite a different cabinet, display
 panel, and keypad, the PRO-2004 and PRO-2006 circuitry  and
 features  were  very  similar.   The  PRO-2006  scanned and
 searched faster and was more sensitive.  Except for the use
 of  a  plastic  case,  the PRO-2006 was equal to, or better
 than the PRO-2004.
        By 1993, the highly prized PRO-2006 was getting long
 in tooth.  Uniden introduced the Bearcat 8500xlt, the first
 Bearcat scanner featuring up conversion and a tuning  knob.
 Radio  Shack's somewhat late response to the 8500xlt is the
 new PRO-2035.
        The PRO-2035 analyzed in this review  was  purchased
 from  a  local  Radio Shack store and bears a serial number
 near 3000.


        The PRO-2035 is about 5/8"  wider  and  1/2"  taller
 than the PRO-2006.  Extra room in the spacious cabinet will
 interest  experimenters  and  companies  who  may   provide
 aftermarket accessories for the PRO-2035.
        The dark plastic case has rounded  corners,  typical
 of  contemporary "European" stying.  The squelch and volume
 knobs are the same dark color as the front panel,  and  you
 can't  see  where  they are set as Radio Shack opted not to
 paint the hairline marker grooves a contrasting color.  You
 can  paint a white groove in each knob using a small bottle
 of White Out  correction  fluid,  a  product  intended  for
 covering typing mistakes.
        Although there is a jack for  running  the  PRO-2035
 from a 12 VDC source, Radio Shack refers to this model as a
 "home scanner."

                     Frequency Coverage

        There is a typographical error  on  page  3  of  the
 owner's  manual which specifies that the PR0-2035 tunes the
 470 - 805.750 MHz range.  Coverage in  this  band  actually
 stops  at  520  MHz  and  resumes  at 760 MHz.  Despite the
 limits cited in the manual, the PRO-2035  tested  for  this
 article  tuned  25 - 520, 760 - 823.995, 849.005 - 868.995,
 and 894.005 - 1300 MHz.
        Lately, the most frequently posed  scanner  question
 on the Internet and computer bulletin boards is, "How can I
 modify my scanner to cover the cellular phone range?"   The
 FCC  no  longer  permits  companies  to sell scanners which
 cover the 800 MHz cellular phone frequencies or  which  can
 be  easily modified to cover them.  As sold in the USA, the
 PRO-2035 does not tune the cellular frequencies directly.
        This raises an interesting question  for  a  product
 reviewer  or  scanner  experimenter:  If he or she finds an
 easy way to expand frequency  coverage  into  the  cellular
 phone  band, should the information be published?  Doing so
 could lead to a product recall.

                       Memory Features

        The PRO-2006 has 400  conventional  memory  channels
 and  10  Monitor  channels  backed up by an ordinary 9 volt
 battery.   The  PRO-2035  has  1000   conventional   memory
 channels  and 100 Monitor channels backed up by a special 3
 volt battery soldered onto the  main  circuit  board.   The
 owner's  manual states memory contents will be retained for
 up to 3 months in the event of a power interruption.
        Both the PRO-2006 and  PRO-2035  have  10  pairs  of
 search  limits,  but  the PRO-2006 permitted searching only
 one range at a time.  The PRO-2035  is  more  flexible  and
 allows  "linking" search ranges together sequentially.  You
 can set search range #1 limits to 46.61  -  46.97  MHz  and
 search  range #2 to 49.61 - 49.97 MHz, for example, and the
 PRO-2035 will alternate searching both ranges.
        Here's a tip: If your favorite search range has  one
 or  two  birdies,  or frequencies you want to skip, you can
 break the range up into two or more sequential  ranges  and
 link them together.
        Not only are there a lot more channels in  the  PRO-
 2035, but several new ways to manipulate them.  By pressing
 a few keys, you can:

   1) zero all 100 memories in any single bank

   2) zero all 1000 memories in all banks

   3) zero all the locked out memories in any bank

   4) display the number of "empty" channels in any bank.  The PRO-2035
 owner's manual refers to memories which contain 0.0000
 as "empty" memories.

   5) move all the nonempty channels in a bank downwards
 to fill in the empty channels in the bank

   6) transfer multiple Monitor channels into one or more banks

   7) transfer all the channels in any bank into the Monitor channels

        With so many channels, the  PRO-2035  needs  another
 feature,  but  it's  missing:  it  should  skip  over empty
 channels automatically.  Although the PRO-2035 scans  twice
 as  fast  as  the  PRO-2006,  it still wastes time scanning
 empty channels unless they are locked out.  The  bulk  move
 operations   listed   above   clear  the  lockout  on  each
 destination channel.  Owners will certainly grow  weary  of
 pressing  the  LOCKOUT  and  MANUAL  keys  for  each  empty
        There are 10 banks of 100 channels each.  Bank 1  is
 for channels 1-100, bank 2 for 102-200, and so forth.  This
 is more difficult to  use  than  the  numbering  convention
 employed  in  the Icom R-7100, where bank 0 is for channels
 0-99, bank  1  for  channels  100-199,  etc.   With  Icom's
 numbering  system,  you can easily tell what bank a channel
 is in by its first digit, e.g., that channel 650 is in bank
 6.   In  the PRO-2035, channel 650 is in bank 7, and that's
 confusing.  All that aside, a better  scheme  would  be  to
 have  more  banks and fewer channels per bank, say 50 banks
 of 20 channels, or even user  definable  banks,  because  a
 bank  of  100  channels  is  really  too large for sensible
        Almost 20  years  ago,  the  Electra/Bearcat  BC-250
 incorporated  a  fantastic  new  feature termed "search and
 store."  One could program  a  pair  of  frequency  limits,
 start an automatic search, and store all active frequencies
 into a special scratchpad memory.  The  active  frequencies
 could  later be recalled and programmed into regular memory
 channels.  Electra's scheme was elegant -- smart enough  to
 store  each  active  frequency  once and only once.  What's
 more, one could store unwanted frequencies,  e.g.,  birdies
 and  paging frequencies, into the scratchpad and they would
 be skipped during conventional searches.  Today's  Icom  R-
 7100 receiver boasts a similar feature.
        Scanner hobbyists  were  hoping  Radio  Shack  would
 offer  a  search  and  store  feature  in  its next premium
 scanner, and it did -- sort of.  The PRO-2035 has  an  Auto
 Store  mode  which stores active frequencies found during a
 search into one or more conventional  memory  banks.   Once
 all  the  empty  channels  are filled, the PRO-2035 emits a
 series of beeps and stops searching.  There is  a  separate
 pair of frequency limits for Auto Store so you won't use up
 one of the 10 pairs mentioned earlier.
        What a pity the Auto Store implementation is not all
 it   could   be.   You  cannot  use  it  to  skip  unwanted
 frequencies.  Worse, it will  store  the  same  frequencies
 over  and over again into empty memory channels.  Let's say
 you program  the  PRO-2035  auto  store  limits  to  search
 between   407   and   419  MHz,  and  specify  that  active
 frequencies will be stored in bank 4.  You start the search
 and  let  it  run  while  you run some errands, hoping that
 while you are away, the PRO-2035 will be catching dozens of
 interesting federal frequencies.
        Upon returning, you find the PRO-2035 snared a  busy
 Veteran's  Administration hospital paging system and stored
 the same  frequency  in  30  channels!   That's  just  what
 happened during the evaluation.  Even with its limitations,
 the Auto Store mode is beneficial and a few new frequencies
 were found while using it.
        Here's a tip not mentioned in the owner's manual  --
 you  can use the Auto Store mode to intentionally store the
 same frequency in several channels.  Set both the lower and
 upper  auto store limits to be the same frequency, open the
 squelch, and start the auto  store  search.   The  PRO-2035
 will  chug  along,  storing  your  favorite police or other
 frequency in all the channels in the banks you selected.
        The tests which follow were performed  by  switching
 an  outdoor  Antenna  Specialists  AV-801  antenna back and
 forth between a PRO-2006 and the PRO-2035.


        Spot checks were  made  to  compare  sensitivity  by
 listening  to the same weak signals on both scanners.  Both
 radios were similarly sensitive except in three  instances:
 the PRO-2035 was slightly more sensitive at 147 and 852 MHz
 and noticeable more sensitive at 460 MHz.
        This could be splitting hairs, as  my  10  year  old
 Electra/Bearcat  BC-300,  an  old  design  optimized  for 4
 bands, beat both Radio  Shack  models  in  the  sensitivity

                        Dynamic Range

        The PRO-2035 and PRO-2006 are high end  models,  and
 people who buy them are more apt to connect them to outdoor
 antennas.  Therefore, it's important that they perform well
 in strong signal environments.
        Perhaps the biggest performance  difference  between
 the   PRO-2006   and  our  PRO-2035  became  apparent  when
 listening to weak signals  in  the  presence  of  a  strong
 station  transmitting  on  another frequency.  The PRO-2006
 has much better dynamic range than the reviewer's PRO-2035.
        Using the PRO-2035, a moderately strong signal  from
 the  460.525  MHz sheriff's repeater 10 miles distant wiped
 out  weaker  signals  on  frequencies  50  kHz  in   either
 direction  and  produced hiss on weak signals 100 kHz away.
 The desense phenomenon was a problem in the 155  MHz  band,
 too.  The PRO-2006 was not affected by these signals.
        To explore the problem  further,  the  PRO-2006  was
 replaced  with a PRO-2005 and the tests run again.  Neither
 the  PRO-2005  nor  PRO-2006  were  desensitized   by   the
 moderately strong signals.

                Images and Spurious Responses

        The PRO-2004/5/6 series, the  portable  PRO-43,  and
 the  PRO-2035  use  "up  conversion,"  but  the  PRO-2035's
 609.005 - 613.5 MHz first IF (intermediate frequency) is  2
 MHz  higher  than  the  earlier  models.   We speculate the
 change  was  made  to  avoid  interference  problems  which
 bothered some owners of the earlier scanners who lived near
 a channel 20 television transmitter.  The TV  signal  mixes
 with  one  of  the  local oscillators and generated a third
 signal near 48.5 MHz, the 2nd IF, causing  interference  on
 several frequencies.
        Although  up  conversion  affords   improved   image
 rejection,   triple   conversion  and  frequency  synthesis
 circuitry are complicated and several  images  were  heard,
 especially on the PRO-2035.
        On both the PRO-2006 and PRO-2035, images of  paging
 transmitters  were  audible  in  the  159  - 162 MHz range.
 Analysis shows these signals to be 771.9975 MHz higher than
 the  displayed  frequency.   For  example, the 931.5125 MHz
 KOR933 paging transmitter, located more than 7 miles  away,
 was heard when the PRO-2035 was tuned to 159.515 MHz.
        A paging image hindered  reception  of  a  sheriff's
 repeater in the next county on 159.15 MHz.  The same paging
 images were present but barely detectable on the  PRO-2006.
 Another  image,  heard  only  by  the PRO-2035, appeared on
 146.075 MHz,  and  it  was  actually  a  904.075  MHz  data
        The PRO-2035 received cellular phone images, reduced
 in  strength,  between  1105  and 1115 MHz.  The difference
 between the actual and displayed frequencies varied:

 PRO-2035        Actual          Difference
 tuned to        transmitted
 (Image)         (Actual)        (Actual - Image)
 --------        -------         -------
 1105.550        870.450         235.100
 1107.875        876.120         231.755
 1110.900        881.100         229.800
 1113.470        886.530         226.940
 1114.840        893.160         221.680

                        New Features

        The new tuning knob  has  a  light  feel  but  is  a
 welcome  feature  nonetheless.   A look inside the PRO-2035
 revealed the tuning knob is connected to a  special  switch
 assembly   rather   than   an  optical  chopper,  or  photo
 interrupter, used in higher price radios and computer mice.
        The knob can be operated as a channel selector or as
 a VFO control.  We discovered a technique, not mentioned in
 the owner's manual, which let's one enter a  frequency  and
 tune  around  without  actually  storing the frequency.  To
 tune around 154.6 MHz, for example,

   1) press MANUAL (if not already in the manual mode)
   2) press 154.6
   3) press TUNE
   4) rotate the knob in either direction to begin tuning

        If you have never used a scanner with a tuning knob,
 you will be pleasantly surprised how handy it is to be able
 to tune around using a knob instead of fighting with the up
 and down keys on the PRO-2006.
        While putting the PRO-2035 through  its  paces,  the
 tuning  knob  was  used  in  the VFO mode to chase down and
 identify a spurious paging  signal,  a  "spur,"  which  was
 drifting up and down the 2 meter ham band.  The spur caused
 a serious interference problem to three area repeaters.
        Chasing a wandering  spur  requires  the  use  of  a
 tuning knob and the PRO-2035 served well.  The PRO-2006 was
 virtually useless in this application.

                    Other Considerations

        The PRO-2035 specifications state  50  channels  per
 second as the fastest scanning speed.  Our PRO-2035 scanned
 slightly faster than 50  channels  per  second  in  a  bank
 loaded entirely with 800 MHz NFM frequencies, and slowed to
 40 channels per second in a bank purposely  loaded  with  a
 mixture of frequencies in different bands and modes.
        Some  scanner  buffs  refuse  to  use  the  priority
 feature  on their radios because priority sampling tends to
 "chop  up"  transmissions  on  nonpriority  channels.   The
 priority  feature  in  the PRO-2035 is well behaved in this
 regard, and one can hardly tell it's enabled.
        While the squelch on the reviewer's PRO-2035 had  an
 acceptable  amount  of  hysteresis,  some users may wish to
 reduce it.  That is, decrease the amount of "play"  in  the
 squelch  control.   One  could  lessen  the  hysteresis  by
 replacing the tiny 100 Kohm surface mount resistor  between
 pins  12 and 14 of IC-2, a TK10420, with a 220K or 330K ohm
        Wine gets better with age.  That's not true with the
 EL   (electroluminescent)   panel  used  to  backlight  the
 displays in the PRO-2004, PRO-2005, and PRO-2006.   The  EL
 panel  grows  dim  as it is used.  To prolong its life, GRE
 replaced the dimmer switch in  later  production  PRO-2006s
 with a switch used to turn off the back light.
        Instead of an EL panel, the  new  PRO-2035  utilizes
 LEDs (light emitting diodes) to illuminate the display, and
 that's an improvement.  Unless overdriven, LEDs  will  work
 reliably for a very long time.


        Being at the top of the Radio Shack scanner line, we
 expect  a  lot from from the PRO-2035.  Its tuning knob and
 memory manipulation  features  are  significant  advantages
 over  the  PRO-2006.   The  discontinued PRO-2006 exhibited
 better dynamic  range  and  fewer  images  and  remains  an
 excellent performer.
        The PRO-2035 is a very good  scanner.   With  a  few
 changes, it could be a great scanner.
        After this review was written, Uniden introduced the
 BC9000XLT  top line base model, which the author tested and
 prefers to the  PRO-2035.   See  the  BC9000XLT  review  in
 Monitoring Times, March 1995 for more information.

                     For Further Reading

 "The  Radio  Shack  PRO-2004  Scanner,"  by  Bob   Parnass,
 Monitoring Times, March 1987.

 "The Radio Shack PRO-2005 Scanner," by  Bob  Parnass,  RCMA
 Journal, August 1989.

 "The Realistic PRO-2006," by Bob Parnass, Monitoring Times,
 October 1990.

 "The Radio Shack PRO-2035," by Bob Grove, Monitoring Times,
 October 1994.

 "Communications  Receivers:  Principles  and  Design,"   by
 Ulrich  L. Rhode and T. T. N. Bucher, McGraw Hill Book Co.,
 1988, ISBN 0-07-05370-1.

 "Radio Communications Receivers," by Cornell  Drentea,  TAB
 Books Inc., 1982, ISBN 0-8306-1393-5.


Copyright 1995,  Bob Parnass, AJ9S        AMPS Wireless Development Laboratory