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       THE NL3ASD MODIFICATION FILES - THE HAM RADIO MODIFICATION - PAGES PAGES E TO HHOMEPAGE
From parnass
Newsgroups: rec.radio.amateur.equipment

From: parnass
Subject: Yaesu FT-23R 2m walkie talkie anthology

Organization: AT&T Bell Laboratories, Naperville, IL

Date: Mon, 20 Sep 1993 13:55:17 GMT

Message-ID: .  Actual tone squelch frequency is

displayed during programming (nice!).  The tiny module ($61)

mounts  above  the  battery  attachment  plate, and does not

extend the radio's length.  CTCSS  modes  are  "Encode"  and

"Encode/Decode" but no decode without encode.



Memory Cloning:A cable from the earphone jack of one FT-23R

to  the microphone jack of another transfers memory contents

(useful for emergencies).  A switch on  the  bottom  of  the

radio  (accessible  by  removing the battery) puts the radio

into clone mode.  You cannot reach the clone switch  if  the

DTMF module is installed.



Scanning: The  FT-23R  has  CHANNEL-SCAN  (all   10,   with

lockout),  PRIORITY  SCAN (checks ch. 1 every 4 seconds) and





__________



 2. DTMF - dual tone multi frequency



 3. CTCSS - continuous tone coded squelch system

























                           - 3 -







BAND SCAN (no presettable  limits).   There  is  no  timeout

resume  scan  mode.   Scan  rate  is  2  preset channels per

second.  Band scan is much faster; 1 MHz in 9 seconds  
kHz/step,  18  sec
(spurious receiver responses) during 140-164 MHz band  scan,

with a shielded 50 ohm dummy antenna.



Instructions:Well written in good  English,  but  the  book

contains NO schematic or block diagram (Boo!).  The receiver

first IF is 10.7 MHz (not listed in specifications).   Being

careful  not  to transmit, I connected the antenna jack to a

spectrum analyzer and found a -6 dBm (75 ohms) local  oscil-

lator  signal  10.7  MHz below the receiving frequency.  The

spectrum analyser revealed a unique signature:the  FT-23R's

battery  saver  feature  turns the receiver off (for 600 ms)

and on (300 ms), in a cycle beginning a  few  seconds  after

the  receiver  is  squelched  (and  not  scanning).   I have

observed no bursts of TVI when the PLL relocks.  Knowing the

IF  allows  using  the image response trick to listen to ATC

while at airports. (Multiply first i.f. by  2,  add  to  the

desired  aircraft  frequency,  tune the radio to the sum; AM

comes through weak but readable.)  I tried it at  the  local

airport;  the Yaesu's FM detector does not perform nearly as

well on AM as does the Icom IC-02AT or IC-28H.



Extended  Frequency  Range: "Circumcising"  the  FT-23R  is

remarkably  simple.   Removing  one  solder  blob  (pad  #7,

clearly marked, 10 o'clock  position  from  the  speaker,  9

o'clock  from the microprocessor) lets the radio receive and

transmit from 140.0 to 163.995 MHz.  Too  bad  it  won't  do

National Park frequencies.



The two circuit boards with  surface  mount  components  are

uncluttered.  When opening the radio, be careful not to lose

the tiny coil spring inside the battery release  button.   I

haven't  measured  receiver sensitivity, nor do I know about

performance in big city RFI; the FT-23R is considerably more

sensitive at 162 MHz weather frequencies than is my modified

Icom IC-02AT.



Power:Receiver drain is 19 mA in power save mode.  The  FT-

23R  operates at any voltage from 6 to 15v.  Three recharge-

able battery options offer small  size,  long  duration,  or

high  power.  Rated output at 7.2 v is 2.5 watts; a friend's

rig and my own both produce 3.5 w with FNB-10  (7.2  v,  600

mAH)  battery  packs. Two replaceable cell battery packs are

available (six AAA and six AA).  Alkaline cells are  invalu-

able for emergency service; AA cells are more cost-effective

than AAA's.  The three NiCd battery packs require three dif-

ferent   wall-charger  types  (15-hour  charge  time).   The

optional automatic fast charger charges any NiCd pack  in  5























                           - 4 -







hours.



Speaker Microphone:One is available from Yaesu.   The  Icom

speaker-microphone works with Yaesu transceivers if a resis-

tor inside the spkr-mic is replaced with a lower value,  and

It still works with Icom radios afterward.



My FT-23R, with DTMF and 7.2 volt 600 mAH battery, was  $249

from some nice folks from Kansas City who didn't soak me for

sales tax, at least overtly.









                  MORE ON THE YAESU FT-23R



                    by Bob Parnass, AJ9S



Frank's comments on the FT23R walkie-talkie were persuasive.

I bought an FT23R, an extra 7.2 V 600 mAH battery, mobile DC

adaptor, PL encode/decode deck, and the AA dry cell case.



I filled the $12 AA dry cell case with  six  550  mAH  Sanyo

NiCd  batteries,  purchased  for an additional $12 at a ham-

fest.



The Yaesu belt clip looks flimsy, so I bought an  ICOM  belt

clip  (for the ICOM mini-talkie) and reamed the holes to fit

the FT23R.  The spring steel ICOM clip  is  $2  cheaper  and

fits my belt better.



If I had bought the Touch ToneTM  pad  with  the  radio,  it

would  have  cost and additional $30.  If pad is $50 if pur-

chased separately.



Since the same radio case is  used  in  the  FT23R  and  its

industrial  cousin,  the FT23R is built rugged, much more so

than its Kenwood and Icom competitors.  Reminds me of how my

Motorola  HT220,  or  a  GE  Pocket-Mate  feels.  The rubber

gasketing on the case top and side is impressive.   In  con-

trast,  the  case  bottom,  near the battery plate, is open,

although dust should be prevented from entering as  long  as

the battery is in place.



My fingers aren't big, but seem huge when trying to push the

closely  spaced  rubber  buttons  or  twist the knobs on the

Yaesu.



After verifying that the stock  radio  worked,  I  carefully

opened the case, then made the modification for full 140-164

MHz coverage.  There appears to be no modification to enable























                           - 5 -







out  of  band receive without transmit.  This made my dealer

nervous, and fearing FCC action, he posted  a  sign  warning

that no out of band receive modification was available.  The

tiny surface mount components on the circuit boards  mark  a

turning point in amateur radio construction, when owners may

no longer be able to service their walkie-talkies.



I connected the FT23R to a variable voltage, current  limit-

ing bench power supply.  The receiver section must have vol-

tage regulation, as increasing the voltage input from 7.2 to

13.6  VDC  caused no difference in receiver current consump-

tion.



The fastest charger available for the  FT23R  is  a  5  hour

unit.   It  contains a timer, rather than the more sophisti-

cated thermistor and temperature-0 sensing arrangement of  the

Kenwood  and  Motorola  rapid chargers.  Rather than buy the

fast charger, I use a bench power supply connected though  a

power  resistor,  and  adjust  the  current  for 180 mA, the

appropriate 5 hour charge rate.4



When in battery save mode, the  current  consumption  alter-

nates between 5 mA and 50 mA.



Based on comparative S-meter readings, the 4.5 inch flexible

antenna  supplied  with the FT23R doesn't hear quite as well

as its longer counterpart.



The method of locking out channels is cumbersome,  and  it's

too  bad  that  channel  0 cannot be locked out of the scan.

There must have been an early batch of 23R's with a firmware

bug,  as my unit was packed with an errata sheet, which said

early units behaved differently when using the priority mode

on certain channels.























__________



 4. I calculate the charge current, in milliamperes, as 1.5

    * C/H, where C is the battery capacity (600 mAH for my

    battery), and H is the desired charge duration in hours.

























                           - 6 -







                    ANOTHER YAESU FT-23R

                       OWNER COMMENTS



                    by Bob Moore WA2JFM5



I just purchased an FT23R, and like it very  much.   It  was

chosen  as the least expensive 2 M walkie talkie with over 3

memories available at the Rochester (NY)  Hamfest.   I  con-

sidered  the  DTMF  pad  as part of the unit and price.  The

unit turns out to also be rugged and well  built;  audio  is

excellent,  and  size is handy.  The PL does need to be pur-

chased as a single (very simple) unit.  Installation of  the

PL  is shown in the manual, and is simple.  The microproces-

sor does all the programming and remembering of PL  frequen-

cies along with the transmit and receiver frequencies.



My only reservation is the relative complexity of  the  con-

trols  --  that seems to be common in modern ham gear -- and

the size of the knobs and buttons.   There  is  a  lot  more

functionality  than  you  would  ever  expect  in  an walkie

talkie.  I would also recommend purchasing the quick charger

and the large battery pack.



I hope you enjoy the unit as much as I have.







                    FT-23R MODIFICATIONS





copied from packet:



 Msg# TSF  Size #Rd  Date  Time From   MsgID        To

33018 BF   5506   0 13-Jan 1158 F1LOU  30537_ON7RC  YAESU
 Sb:FT23/73/211 mods





               YAESU FT-23R case disassembly:





 1.  Remove the black screws  from  the  top  panel  of  the

     radio.

 2.  Remove the knobs.

 3.  Remove the black screws from  the  rear  panel  of  the





__________



 5. Bob Moore WA2JFM, GCA/Tropel Div. Rochester, NY 14450,

    ihnp4!tropix!rcm

























                           - 7 -







     radio.

 4.  Remove the battery.

 5.  Remove the 6 screws on the bottom of the  radio,  where

     the battery attaches.

 6.  CAREFULLY remove the front panel of the radio.

 7.  In the left  of  the  microprocessor  and  battery  are

     several  printed  circuit jumpers.  The jumpers labeled

     7, 8 and 9 are for the frequencie mods, like  explained

     in the following.

 8.  Re-assemble the radio in the  reverse  order  of  these

     steps.

 9.  The Microprocessor will loose all what the memory  con-

     tains.





                YAESU FT211/23/73 Band Mods



The uP's in the FT-23/73 and the FT-211 can be set for  many

frequency and memory mode combinations. These modes are con-

troled by the jumpers (solder pads) marked 7,8 and 9 on  the

"CONTROL UNIT" board of either radio. Here is a list of what

is possible:





                   JUMPER         FREQUENCIES

                7    8    9         COVERED



               open open  in     140 to 164 MHZ

               open  in   in     140 to 160 MHZ

                in  open  in     144 to 148 MHZ

                in   in   in     144 to 146 MHZ

               open open open    220 to 550 MHZ

               open  in  open    440 to 450 MHZ

                in  open  in      50 to 300 MHZ

                in   in  open    430 to 440 MHZ



The FT-211 has separate VCO's for transmit and  receive  and

will lock over about 38 MHZ from approx. 130 to 180 MHZ. The

FT-23 has only one VCO and the overlapping lock range (Xmt &

Rcv)  is  about  25  MHZ from approx.  135 to 175 MHZ. Don't

forget, if you adjust the VCO you must realign  every  elec-

tronically  tuned  stage  in the front-end of the radio. The

transmitters can be tuned for somewhat higher  power  output

above 164 MHz but at a great power loss at 2m.



The non-amateur (commercial) memory mode  will  cause  these

functions changes:





  1.  When in the  MR  mode,  the  channel  number  will  be

      displayed instead of frequency. You can toggle back to























                           - 8 -







      the original "amateur" mode display by pressing  F.  Pressing F bring you back to com-

      mercial mode.  However, when switching from D  to  MR,

      the display will always revert to the commercial mode.



  2.  The function of the Dot button  will  be  exactly

      reversed. That means now you can press just one button

      (Dot) to get into or out of the Primary  function  The

      Pri  funtion  (in  memory mode) will be indicated by a

      large "P" on the left side of the display.



  3.  The only indication of low power operation is  in  the

      memory  mode.  A  "C"  will  appear  in the upper left

      corner of the display (where the primary "P"  used  to

      be). The bargraph will always read 100%.



  4.  The band scan is now even more useless.  The  uP  will

      painfully count from 50 to 300 MHz.







                     FT23/73 in packet-radio:



      If you want to work in packet-radio, open jumper 10 to

      dissable the battery save.



      73's de Phil, F1LOU


--

==============================================================================

                       Copyright 1993,  Bob Parnass, AJ9S

         AT&T Bell Laboratories  -  parnass


SOURCE: The QRZ Windows Ham Radio CDROM



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