Msg Nr. : 69010 Da : HB9IQW Per : ICOM @EU Tipo/status : B$ Data/ora : 1121/0353 Dimensione : 8089 Titolo : Alcune modifiche per l'IC 24 Bid (Mid) : 20B307HB9OS de HB9IQW @ HB9OS Hello ICOM-Users, Following the modification-document for enabling the 1750Hz-tone and extended transmitting with the ICOM IC24AT Dualbander: Enabling Tone Burst on the IC-24AT by Eric A. Cottrell WB1HBU BACKGROUND Are you going over to Europe and once again facing the age-old tone burst problem? Are you tired of carrying that home-made tone encoder that looks like a bomb detonator? Are you tired of the hours practicing to whistle at 1750 Hz? If you own a IC-24AT then you have hope. I looked into the tone burst problem several years ago when I owned a 02AT walkie. Tone Burst could be done by adding a board, but this sacrificed the DTMF board (The most important feature for American Hams). I recently bought an IC-24AT walkie. I noticed on the schematic that the microprocessor generated the 1750 tone burst! Looking at the Service manual confirmed that the same part number is used for the microprocessor on all versions. Two resistors (R61 and R62) are removed from the non-european versions to prevent the tone burst from going into the transmit audio. I thought it was strange that they installed the adjustment pot (R60) in all models until I realized that it served as a load for the output. Another problem is that european repeaters use the seqment from 430 - 440 Mhz and US repeaters use 440 - 450 MHz. I figured that doing the "out-of band" transmit mod would solve this problem. I ordered the diodes and resistors and got the work. I was upset when after doing the mods, the tone burst did not work! I found that an additional diode (D5) has to be removed for the tone burst to work. The diode pattern ends up being the same as the italian version of the 24ET, except D13 is removed. Nothing is lost with doing the mod. The DTMF, the PL, and the Tone Squelch (UT-50) still work. The only disadvantage is the IC-24AT resets to european settings, but they can be set back to american settings with the set function. I believe that a similar mod can be done to the 2SAT and 4SAT series. I only have a 3SAT, but opening the unit shows similar traces on the logic board. The adjustment pot is not installed on the 3SAT. PROCEDURE WARNING: The following procedure deals with surface mount components. If you are unfamilar with surface mount let someone who is familar with surface mount do the mod. Reworking surface mount stuff is a delicate operation. If you are still game read the QST articles on Surface mount first and get a surface mount practice kit. Mimimum equipment need: small tweezers, small gauge silver solder, low wattage soldering iron (prefered temperature control) with a small tip, small cutters, a magnifier that does not need to be held and a vise or other clamp to hold the walkie. WARNING: This mod may void your warranty with ICOM. The author (Eric A. Cottrell) does not offer ANY warranty, express or implied. 1. Order the two resistors and two diodes from ICOM. You may want to order extra in case you drop one. The resistors are tiny and can be hard to handle. The diodes are alittle better. You may want to order the service manual to get your bearings. The part numbers are: (1) 7030003800 R61 Resistor ERJ3GEYJ 1M ohm (marked as 105) (1) 7030003640 R62 Resistor ERJ3GEYJ 47K ohm (marked as 473) (2) 1750000130 D7, D12 Diode DA204U (marked as K) 2. Make note of memory channels and set parameters of the unit. 3. Open the case. Be careful not to lose the spring in the battery release assembly. When the two halfs are opened the logic board is the board in the half with the display and keypad. 4. Located four empty solder pads on the logic board near the small (5 conductor) flex cable. Install R62 (47K) first using the two pads closer to the small flex cable.The orientation is the same as nearby resistors. Be careful not to make any solder bridges or burn the flex cable. Use silver solder. Install R61 (1 Meg) next to R62 on the two remaining pads. 5. Do the out of band transmit mod (the following from the mod): o Locate and remove the diode device in position D8 o Locate the vacant position of diode D7 and attach one of the DA204u diodes at that location. o Locate the vacant position of diode D12 and attach the other DA204u diode at that position. o If diode D13 has not been removed, remove it. The unit will now transmit out of the amateur bands. 6. Locate and remove the diode device in position D5. This enables the tone burst. 7. Reassemble the unit. Do reset the CPU as shown in the inside front cover of the manual and reprogram the memory channels and settings. USAGE If a repeater is up, tone burst is not needed. To bring up a repeater, press the PTT twice rapidly and hold down the button during the second press. You should hear the 1750 Hz tone through the speaker. Only about 1/2 of a second tone is needed to open a repeater. While I assume you would not dare transmit out-of-band in a foreign country, I have learnt from locals that listening to police and commercial services in some european countries (like the UK) is illegal. Be discreet and do not walk the streets of the town center with the speaker blaring the local law enforcement frequency. Arrest with possible fines and/or jail time is not the best way to spend a vacation. I am planning to program the memory channels with all the repeater and most simplex frequencies and set the vfo to 1 MHz frequency entry to curtail accidental out-of-band transmissions. 73 Eric. WB1HBU @ K1UGM internet: eac@world.std.com CIS: 76327,515 -or- 76327.515@compuserve.com *** the following info shows the location of D5 in the IC-24AT: +---------+ I I I I I micro I I Contr. I I I I I +---------+ * * * * D5d d6d * * * * * dd7 d8D * * * * * * * d11 dd12 * * o o d13 d14 o o In my Handy, only D5 and D6 are mounted. I measured the pins with a multimeter and found following: -D5 is a pair of diodes were the under, center pin is the cathode of both and the upper two pins are the anodes -D6 is only one diode where the upper left pin is the anode and the lower, center pin is the cathode. The upper right pin of D6 is not used. Good luck and best 73 de Patrik, HB9iQW @ HB9OS ============================================================================== Date: 17 May 90 15:54:21 GMT From: hpcc01!col!kenw@hplabs.hp.com (Ken Wyatt) Subject: IC-24AT Receive Mods At the request of several interested hams, I am posting the modification instructions for the Icom IC-24AT. This set of instructions originated from Icom America and was downloaded from the Icom Library of HamNet (Compuserve). Ken WA6TTY (kenw@col.hp.com) ----------------------------------------------------------------------- IC-24AT Undocumented Features - (from ICOM) The IC-24AT dual band handheld had three additional features that are not described in the owners manual. These have been left out of the owners manual because some countries restrict the use of the radio in these modes. AM AIRCRAFT RECEIVE PLUS 740 to 960 MHz RECEIVE Remove D13 from the main logic board (this diode may already be removed by ICOM in some units). This diode may already be removed in some radios. D13 is on the main logic board and is a discreet diode (one of the two in the radio) near the center of the board. It is the left discreet diode of the two on the board when the radio is open and held with the controls away from you. Simultaneously hold "Light", "B", and "#" keys depressed and turn power on. It is important to note that the radio will not meet specifica- tion on the out of band receive frequencies that are enabled with this modification. DIRECT KEYBOARD ENTRY of 100 MHz FREQUENCY Simultaneously hold "Light" and "3" keys depressed and turn power on. CROSS BAND REPEAT (simplex) Remove D14 from the main logic board (this diode may already be removed by ICOM in some units). The diode is a discreet diode to the right of D13 (from above) and directly beside it. Simultaneously hold "Funct" depressed and push "C". To turn on cross band repeat: Hold "Funct" depressed then push "5" and then push "D". To turn off cross band repeat simultaneously hold "Funct" and "D" depressed. 2-14-90 ============================================================================== r 2381r 2381 Date: 28 Apr 90 00:04 Message-ID: <5490@N5WX> From: N5WX@N5WX To: MODS@ALLONT Subject: IC24AT New Info Path: NT8V!VE3WZL!VE3JEZ!KI4BT!WB9TYT!KC9BK!WA9KEC!N9BYS!N9GTM!AF9M!WA9UXP!NQ9Q!KD9LP!KD9QB!WJ9U!KK9G!WD4PPF!K4BFT!WB4GHL!N5WX There is a later version of IC24AT that does not require D13 as in a previous bulletin. All programming of extended frequency coverage is available from the keyboard. To Enable extended freq coverage - 75 to 195, 200 to over 900 Mhz. Hold down Light, and B and turn on, wait for display to stop. To enable 10 and 100 Mhz digit entry direct from keyboard: Hold down light and 2 key and turn on, then turn off. Hold down light and 3 key and urn on. Gud luck @ 73 Ron, N5WX VE3PZR de VE3GYQ: at 0221z on 900508 B,C,D,H,?,I,J,K,L,M,N,P,R,S,T,U,V,W > bb AX25 session 1 closed: Normal Hit enter to continue ============================================================================== 8506r 8506 Date: 03 Sep 90 16:31 Message-ID: <22513@VE4KV> From: VE4KV@VE4KV To: ALL@ALLONT Subject: Mod for IC-24AT Path: VE3EUK!VE3INF!VE3FJB!VE3KYT!VE4KV OUT OF BAND MODIFICATION OF THE ICOM IC-24AT The Icom IC-24AT is truly a remarkable unit. Having it's genesis in the IC-R1, Icom's extremely wide band Hand Held Receiver, it is capable of receiving a wide range of frequencies, as well as being able to transmit on short excursions, outside of the amateur two meter and 440 MHZ. bands. The more current models can be modified to receive out of band, by a simple software (not necessary to physically open the transceiver) procedure as follows; o Turn the power switch off. While simultaneously holding the "light" button, the "B" button, and the "#" button, turn the radio on. All elements of the display will light up. Continue holding the buttons until the display goes out. It may be helpful to have a buddy give you an extra hand during this procedure....Your unit will now receive out of band. The older models of this transceiver, require the removal of diode D13, before performing the above procedure. D13 is on the main logic board and is a discreet diode near the center of the board. It is the diode on the left of the two on the board when the radio is open and held with the controls away from you. The "stock" transceiver, was also not designed, to provide full direct keyboard entry of the operating frequency. This can also be modified by one or both of the two procedures below; o To directly key in the 10Mhz. frequency, simultaneously hold the "light" button and the "2" button, while turning the radio on. o To directly key in the 100Mhz. frequency, simultaneously hold the "light" button and the "3" button, while turning the radio on. The modification of the unit to enable it to transmit out of the amateur bands is a fairly simple procedure. It is however, complicated by the fact that the construction technique used in this transceiver is "Surface Mounted Technology." If you have no experience dealing with this technology, you may well be better advised to defer this procedure to someone who has. It is extremely small and delicate, and is best done with specialized equipment. Also, because the unit may not be FCC type accepted for all the frequencies on which it can then transmit, it may not be legal for you to use it, despite the fact you may be licensed to transmit on those frequencies. This information is provided only for those who are licensed for and want to use the unit on MARS and CAP frequencies, where there are no type acceptance restrictions. The procedure is as follows; o Order a couple of DA204u diodes from Icom or your Icom dealer. These are a special three terminal device with two diode in one package. They are very very small, about half the size of one of the key buttons on the touch tone pad. o Locate and remove the diode device in position D8 o Locate the vacant position of diode D7 and attach one of the DA204u diodes at that location. o Locate the vacant position of diode D12 and attach the other DA204u diode at that position. o If diode D13 (procedure above) has not been removed, remove it. The unit will now transmit out of the amateur bands. The IC-24AT can also function as a Mini Repeater transmitting on the UHF band while simultaneously receiving on the VHF band, or vice versa. This procedure requires both a small hardware as well as a software modification, and is performed as follows; o Locate diode D14. It is located adjacent to the location for diode D13 (see above procedure). Clip or remove it. o To enable Mini Repeater operation 1. Push and hold the "Function" key and then the "C" key. 2. Push and hold the "Function" key and then the "5" key and the "D" key. o To cancel the Mini Repeater operation, push and hold the "Function" key and then push the "D" key. The above modifications provided the following capabilities with my particular unit. FREQUENCY COVERAGE (VHF) RECEIVE TRANSMIT 74.9 Mhz. - 127.9 Mhz. OFF 138.0 Mhz. - 168.0 MHz. 138.0 Mhz. - 159.0 Mhz. 174.1 Mhz. - 189.69 Mhz. OFF 200.0 Mhz. - 287.22 Mhz. OFF 310.0 Mhz. - 349.0 Mhz. OFF (UHF) 355.0 Mhz. - 409.98 Mhz. OFF 412.37 Mhz. - 498.0 Mhz. 410.5 Mhz. - 470.0 Mhz. 792.85 Mhz. - 966.66 Mhz. OFF Receive sensitivity throughout both of the Ham bands was better than .5 of a microvolt. Sensitivity in the 200 Mhz. range was a disappointing 1 millivolt and in the 800 Mhz. band a good .7 of a microvolt. Remember, while the unit will receive on those frequencies, it is illegal to monitor cellular telephone communications. Good luck with your unit. "73" Joe Taylor, W9JO ============================================================================ Msg Nr. : 154584 Da : IW3GRX Per : TMP Tipo/status : PN Data/ora : 0219/1757 Dimensione : 6426 Bid (Mid) : 23512_IW3GRX Titolo : Alcune modifiche per l'IC24 **************************************************************************** r 2381r 2381 Date: 28 Apr 90 00:04 Message-ID: <5490@N5WX> From: N5WX@N5WX To: MODS@ALLONT Subject: IC24AT New Info Path: NT8V!VE3WZL!VE3JEZ!KI4BT!WB9TYT!KC9BK!WA9KEC!N9BYS!N9GTM!AF9M!WA9UXP!NQ9Q!KD9LP!KD9QB!WJ9U!KK9G!WD4PPF!K4BFT!WB4GHL!N5WX There is a later version of IC24AT that does not require D13 as in a previous bulletin. All programming of extended frequency coverage is available from the keyboard. To Enable extended freq coverage - 75 to 195, 200 to over 900 Mhz. Hold down Light, and B and turn on, wait for display to stop. To enable 10 and 100 Mhz digit entry direct from keyboard: Hold down light and 2 key and turn on, then turn off. Hold down light and 3 key and urn on. Gud luck @ 73 Ron, N5WX VE3PZR de VE3GYQ: at 0221z on 900508 B,C,D,H,?,I,J,K,L,M,N,P,R,S,T,U,V,W > bb AX25 session 1 closed: Normal Hit enter to continue Copied from the QRZ! Windows Ham Radio CDROM ************************************************************************* 8506r 8506 Date: 03 Sep 90 16:31 Message-ID: <22513@VE4KV> From: VE4KV@VE4KV To: ALL@ALLONT Subject: Mod for IC-24AT Path: VE3EUK!VE3INF!VE3FJB!VE3KYT!VE4KV OUT OF BAND MODIFICATION OF THE ICOM IC-24AT The Icom IC-24AT is truly a remarkable unit. Having it's genesis in the IC-R1, Icom's extremely wide band Hand Held Receiver, it is capable of receiving a wide range of frequencies, as well as being able to transmit on short excursions, outside of the amateur two meter and 440 MHZ. bands. The more current models can be modified to receive out of band, by a simple software (not necessary to physically open the transceiver) procedure as follows; o Turn the power switch off. While simultaneously holding the "light" button, the "B" button, and the "#" button, turn the radio on. All elements of the display will light up. Continue holding the buttons until the display goes out. It may be helpful to have a buddy give you an extra hand during this procedure....Your unit will now receive out of band. The older models of this transceiver, require the removal of diode D13, before performing the above procedure. D13 is on the main logic board and is a discreet diode near the center of the board. It is the diode on the left of the two on the board when the radio is open and held with the controls away from you. The "stock" transceiver, was also not designed, to provide full direct keyboard entry of the operating frequency. This can also be modified by one or both of the two procedures below; o To directly key in the 10Mhz. frequency, simultaneously hold the "light" button and the "2" button, while turning the radio on. o To directly key in the 100Mhz. frequency, simultaneously hold the "light" button and the "3" button, while turning the radio on. The modification of the unit to enable it to transmit out of the amateur bands is a fairly simple procedure. It is however, complicated by the fact that the construction technique used in this transceiver is "Surface Mounted Technology." If you have no experience dealing with this technology, you may well be better advised to defer this procedure to someone who has. It is extremely small and delicate, and is best done with specialized equipment. Also, because the unit may not be FCC type accepted for all the frequencies on which it can then transmit, it may not be legal for you to use it, despite the fact you may be licensed to transmit on those frequencies. This information is provided only for those who are licensed for and want to use the unit on MARS and CAP frequencies, where there are no type acceptance restrictions. The procedure is as follows; o Order a couple of DA204u diodes from Icom or your Icom dealer. These are a special three terminal device with two diode in one package. They are very very small, about half the size of one of the key buttons on the touch tone pad. o Locate and remove the diode device in position D8 o Locate the vacant position of diode D7 and attach one of the DA204u diodes at that location. o Locate the vacant position of diode D12 and attach the other DA204u diode at that position. o If diode D13 (procedure above) has not been removed, remove it. The unit will now transmit out of the amateur bands. The IC-24AT can also function as a Mini Repeater transmitting on the UHF band while simultaneously receiving on the VHF band, or vice versa. This procedure requires both a small hardware as well as a software modification, and is performed as follows; o Locate diode D14. It is located adjacent to the location for diode D13 (see above procedure). Clip or remove it. o To enable Mini Repeater operation 1. Push and hold the "Function" key and then the "C" key. 2. Push and hold the "Function" key and then the "5" key and the "D" key. o To cancel the Mini Repeater operation, push and hold the "Function" key and then push the "D" key. The above modifications provided the following capabilities with my particular unit. FREQUENCY COVERAGE (VHF) RECEIVE TRANSMIT 74.9 Mhz. - 127.9 Mhz. OFF 138.0 Mhz. - 168.0 MHz. 138.0 Mhz. - 159.0 Mhz. 174.1 Mhz. - 189.69 Mhz. OFF 200.0 Mhz. - 287.22 Mhz. OFF 310.0 Mhz. - 349.0 Mhz. OFF (UHF) 355.0 Mhz. - 409.98 Mhz. OFF 412.37 Mhz. - 498.0 Mhz. 410.5 Mhz. - 470.0 Mhz. 792.85 Mhz. - 966.66 Mhz. OFF Receive sensitivity throughout both of the Ham bands was better than .5 of a microvolt. Sensitivity in the 200 Mhz. range was a disappointing 1 millivolt and in the 800 Mhz. band a good .7 of a microvolt. Remember, while the unit will receive on those frequencies, it is illegal to monitor cellular telephone communications. Good luck with your unit. "73" Joe Taylor, W9JO Copied from the QRZ! Windows Ham Radio CDROM ***************************************************************************