Modifications for the ICOM
created 28-03-2002 from www.mods.dk (AH-4) (AT-160) (AT-500) (AT-500) (I290) (IC-02) (IC-02) (IC-02) (IC-02) (IC-02) (IC-02) (IC-02) (IC-02) (IC-02) (IC-03) (IC-04) (IC-04) (IC-04) (IC-04) (IC-04) (IC-04) (IC-1200) (IC-1271) (IC-1271) (IC-1275) (IC-1275) (IC-1275) (IC-1275) (IC-1275) (IC-1275) (IC-1275) (IC-1275) (IC-1275) (IC-1275) (IC-1275) (IC-2) (IC-2) (IC-2) (IC-2) (IC-2) (IC-2) (IC-2000) (IC-207) (IC-207) (IC-210) (IC-2100) Icom, AH-4, AH-3 ( automatic antenna tuner ) connection to any radio. English language Using the AT-160 with the IC-706MKII English language AT-500 Automatic Antenna Tuner Modification English language ICOM AT-500 Tuner Hint English language Icom I290 scan modification English language Band expansion modification for IC-02AT English language Audio modification for IC-02 AND IC-04 English language IC-02A Modified PLL rigs English language Low audio speaker mike on IC2A, 3A, 4A OR 02AT English language ICOM 02/03/04 & Vox Unit English language Another band expansion mods for Icom IC-02 English language For increased receive audio and improved response English language To increase the memory scan and search scan speed English language ICOM HS-10SA VOX for IC-02AT Mods English language ICOM 02/03/04 & Vox Unit English language ICOM 02/03/04 & Vox Unit English language Out of band modification for IC-04 English language Audio modification for IC-02 AND IC-04 English language Low audio speaker mike on IC2A, 3A, 4A OR 02AT English language TX delay may be excessive at low temperatures English language IC-04E fuer 9k6 German language Expanded RF 870 - 960 MHz for ICOM IC-1200 English language VOX of an IC-271,471,1271 usable for FM English language RAM Card Backup Battery Replacement Instructions English language IC-1275 Freq. steps mod English language Power control modification English language Restoration of pass band tuning English language Splitting into RX- and TX paths English language Modification of cw pass band (BFO) English language Disabling of SBB squelch English language Very fast AGC English language SSB RF Gain English language Tuning speed English language Frequency range & CTCSS tones English language IC 475H / 1275E mod for 9k6 (G3RUH) use English language Modification For IC-2AT English language Low audio speaker mike on IC2A, 3A, 4A OR 02AT English language ICOM IC-2AT internal antenna connection problem English language ICOM IC-2GAT ext frq for Transmit English language IC-2AT, If transmit RF indicator notwork properly English language Icom IC-2GXAT open RX English language Icom IC-2000 Extended RX/TX Mod English language Band expansion for IC-207 English language Band Expansion for IC-207H English language Schematic of IC-210 English language Icom IC-2100H Extended Transmit Mod English language
(IC-2100) (IC-211) (IC-22) (IC-22) (IC-22) (IC-22) (IC-22) (IC-22) (IC-228) (IC-229) (IC-229) (IC-229) (IC-2320) (IC-2330) (IC-2330) (IC-2340) (IC-2340) (IC-2340) (IC-2350) (IC-24) (IC-24) (IC-24) (IC-24) (IC-24) (IC-24) (IC-24) (IC-24) (IC-24) (IC-240) (IC-2400) (IC-2400) (IC-2410) (IC-2410) (IC-2410) (IC-2410) (IC-2410) (IC-2410) (IC-2500) (IC-2500) (IC-251) (IC-251) (IC-251) (IC-260) (IC-27) (IC-27) (IC-2700) (IC-2700) (IC-2700) (IC-271) (IC-271)
Expand receiver for IC-2100H EUR version English language IC-211 mod English language Icom IC22S Packet Modification English language IC-22S mods for 5 KHz step English language Step modification (packet radio operation) English language Band segment modification English language Recieve SSB and CW on IC-22S English language Modifying the IC22A for 9600 baud operation English language IC-228 mods English language IC-229H, and AM aviation band modification English language IC-229H & 9600 bauds (Anglais) English language IC-229H Fix CPU/Display board English language Extended RX/TX English language IC2330A expanded range English language IC-2330A expanded range (another way) English language IC2340H att modification English language Some mods for the IC-2340H English language IC-2340 mods English language IC-2350 expand RX/TX and Crossband rep English language Frequency expansion for IC24 English language Cross-band repeater operation IC-2 English language Out of band modification of the ICOM IC-24AT English language IC-24AT ext frquency English language IC-24AT Keyboard command summary English language IC-24AT sensitivity English language IC-24AT enabling the burst-tone English language IC-24 auf 9600 Baud German language Tip to to function bottom for IC-24 English language 12,5 Khz mods for IC-240 English language ICOM 2400A mini repeater function English language IC-2400 144/430 9K6 mod Other language Expansion of receive range English language 800 MHz antenna input English language Cross-band repeat English language IC-2410 Dual Band External & Mike Remote Codes English language IC-2410 Modification area as follows. New and old version English language IC-2410 TX modification English language Run 9k6 with an Icom IC-2500 (70cm/23cm TRX) English language Umbau des ICOM IC-2500E auf 9600 Baud German language Modifikcation af IC-251 for 9600 baud English language Modifications for the ICOM IC-251 English language IC-251 Receive-repair English language IC-260E auf 9600BD German language IC-27 mic-connector mods English language ICOM IC-27H 2M transceiver for use with the 9k6 English language IC-2700 RX/TX expansion English language IC-2700 Cross Band Repeater English language Enabling ICOM 2700H remote operation English language PSK Transmit Audio Modification for ICOM IC275 & IC271 English language VOX of an IC-271,471,1271 usable for FM English language

This modification is read 515 times.

(IC-1275) Tuning speed

The tunning speed is set to a defaults of 100Hz, 1kHz, 5kHz or 1MHz depending on front plate setting and mode. These settings can be manipulated by D41 - 46 at the front plate. At least a setting of 10kHz is also available.
This modification is read 510 times.
(IC-1275) Frequency range & CTCSS tones
The IC-275 have capability to cover 138 - 174 MHz and the IC-475 has capability to cover 430 - 450 MHz. Because of hardware restrictions they might not be fully up to specifications in all of the band, but an extended range can be interesting for e.g. use with a transverter. It seems that the IC-275 has a parallel wide band preamp, that can be switch via the WBT pin on RF-YGR PCB. In the European versions the transceivers are wired for 1750 Hz repeater call, and they have no CTCSS capability. The transceivers have a built-in CTCSS encoder, so these functions can be restored. Both of these version dependent functions can be set by the diode matrix: D20 - D24 in the logic unit. I do not know the exact mapping, but a lot can be derived from studying the different frequency ranges and the diode matrix coding table found on the schematic diagram.
This modification is read 527 times.

20-04-2000

(IC-1275) IC 475H / 1275E mod for 9k6 (G3RUH) use
This is original the 9600 baud mod for the IC-475H. Yann - F1NGP f1ngp@wanadoo.fr.MODIFICATION.NET has reported this to me. I've tried the MODS for 9600bds for my ICOM IC-475H. Working OK. I've tried to build the same mod on my 23cm ALL-MODE ICOM IC-1275E as the MAIN UNIT is the same as the 475. ALL WORKING OK ! Thanks to Yann. The original ICOM IC-475H 9600 baud modification. Warning: I'm writing this message to help out owners of Icoms 475 H to modify their transceivers for use with a G3RUH modem. I will not take any responsability if you destroy your transceiver while doing this modification. This modification requires that you have a minimum experience in soldering and electronics. If you feel that you cannot undertake this modification, don't even try it and leave it up to someone else!
Reception of FSK signal: The reception has to be taken directly off the demodulator chip. This is the chip referenced as IC6 (MC3357P) on the electronics diagram. Demodulator output is on pin 9 of this chip. You will have to run a SHIELDED wire from this pin to the outside of your transceiver. I've done this by connecting it to pin 11 of J4 (AQS socket on the back). This pin is originally unused. But this is not as easy as it sounds; you will have to unscrew both sides of the transceiver and undo a lot of parts to finally solder on a very small plug! Be careful here. Transmission of FSK signal: The FSK signal is simply injected on pin 2 of the AQS socket. BUT, as you will see on the electronic diagram, this signal goes through a variable resistor (R152) and a capacity (C142). So you might encounter two problems: not enough and/or distorted modulation. In my case, I used a MFJ 9600 Bauds card and I had to put the level almost to the maximum on this board, while also putting the variable resistor to the minimum! The capacity on the other hand is very very bad for the modulation of the FSK signal as the transceiver should respond to DC! My solution: simply short circuit the capacity (C142). This is most easily done directly on the components side of the circuit board, since it's very difficult to take it out of the transceiver. Other signals: You will be able to put the PTT line to pin 6 and the ground to pin 1 of the AQS socket. You will also notice that on pin 13, you have 13.8 V available. This can be used to power the TNC for example. I have now a much more stable 9k6 signal than before, when I still had the C142 in the line. Although, this was reportedly been working for other people, it simply didn't for me! Maybe you can avoid short circuiting the capacity, so try it first (although I doubt it!). I hope this will help somebody and if you have any more questions, don't hesitate to contact me at my homeBBS: HB9VBC @ HB9IAP.SROM.CHE.EU

This modification is read 790 times.
(IC-24) 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; 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; To directly key in the 10Mhz. frequency, simultaneously hold the "light" button and the "2" button, while turning the radio on. 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; 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. Locate and remove the diode device in position D8 Locate the vacant position of diode D7 and attach one of the DA204u diodes at that location. Locate the vacant position of diode D12 and attach the other DA204u diode at that position. If diode D13 (procedure above) has not been removed, remove it.

(IC-275) Eliminate possible spurious emission when thermal switch has turned on during TX
May 1, 1989 Procedure 1. Remove top and bottom covers. 2. Remove PA section from radio. 3. Remove shield from power amplifier. 4. Replace R7 (originally 10K 1/4W) resistor with a 1K 1/4 watt resistor (ICOM part number 915-01165). 5. Replace R8 (originally 10K 1/4W) resistor with a 1K 1/4 watt resistor (ICOM part number 915-01165). 6. Replace the shield on the PA section. 7. Replace the PA section in the radio. 8. Replace the top and bottom covers.
This modification is read 671 times.
(IC-275) Frequency range & CTCSS tones
This modification is read 742 times.
(IC-275) Power control modification
This modification is read 757 times.
(IC-275) Restoration of pass band tuning
This modification is read 707 times.
(IC-275) Modification of cw pass band (BFO)
Note: The BFO coils are switched in successively to give the required offset from the LSB frequency. Therefore adjusting CW-T also changes USB/CW-R.
Re-adjusting all of the BFO frequencies is a good idea in any case to compensate for crystal aging. If the passbands sound different in LSB and USB it is a sure sign of mis-alignment due to crystal drift - they should be more or less the same. Disabling of SBB squelch Problem: Squelching is nice to have in FM mode, but it doesn't really work for SSB, where you will be looking for weak signals. Therefore you have to adjust the squelch level every time you change mode. Furthermore I enjoy using FM as a monitoring mode on the SSB calling frequency, so changing the mode happens quite often. Solution: The solution is quite simple. Just cut the connection to the SSB input of the squelch circuit in some way. Implementation: The easiest way to break the connection is to connect the base of Q7 to ground. The base is the lead facing into the centre of the PCB.
This modification is read 667 times.
(IC-275) Disabling of SBB squelch
Problem: Squelching is nice to have in FM mode, but it doesn't really work for SSB, where you will be looking for weak signals. Therefore you have to adjust the squelch level every time you change mode. Furthermore I enjoy using FM as a monitoring mode on the SSB calling frequency, so changing the mode happens quite often. Solution: The solution is quite simple. Just cut the connection to the SSB input of the squelch circuit in some way. Implementation: The easiest way to break the connection is to connect the base of Q7 to ground. The base is the lead facing into the centre of the PCB.

This modification is read 2160 times.

20-10-2001

(IC-2800) Screen saver Turn OFF option for IC-2800
Author: Chuck Lynn - stang@tds.net.MODIFICATION.NET
When the unit is turned off, simultaneously depress the "CHANG/L" key and the "POWER" key. Both located on the bottom corners of the control head. Sceen saver mode will be suspended. To reactivate sceen saver mode repeat the above step. 73 KG4FKU Chuck
This modification is read 2132 times.

13-01-2002

(IC-2800) Cross Band Repeat for IC-2800
Author: KC5VCF - KC5VCF@hotmail.com.MODIFICATION.NET
To cross band repeat with the IC2800 Hold down simutanisuly CHG/L and both MAIN/EDIT buttons.
This modification is read 1221 times.

17-02-2002

(IC-2800) Enable crossband function for IC-2800
Author: - helmut.knaak@t-online.de.MODIFICATION.NET
Unsolder or cut D 60 (near W 13) Press "Main UHF,Main VHF,Chg/L" For 2 seconds, crossband will be enabled.
This modification is read 649 times.
(IC-281) Crossband repeat
To enable crossband repeat press and hold the BAND key and the SET key for about a second, a flashing L will appear in the lower right. To turn off hold the SET key. Unfortunately code squelch does not seem to work when crossband repeat is enabled. Don't know about tone squelch.
This modification is read 877 times.
(IC-281) Extended Receive for IC-281
To enable extended receive a jumper has to be removed. To enable extended transmit a diode has to be removed. I have only tested the extended receive which gives you from 118-174.995 and 320-479.995. Open the case by removing all the screws on the top, bottom and left/right sides and separating the top and bottom covers from the chassis. Next remove the plastic front panel that covers the logic circuit board by removing the two top and two bottom screws that attach it to the chassis. Next remove the front panel logic board by taking out the four front screws that attach it to the chassis. Position the logic board so that the side normally near the chassis is on top and a round flat battery attached via leads is visible with the connector near the bottom and the cut out at the bottom right. Below the battery on the lower right there are a number of diodes, most likely surfaced mounted. Look just to the left of the diodes, there will be a very small surface mount jumper at the bottom (-#WW#- on diagram below). There is no silk screen on the board to identify it (on mine at least) but the part itself may have a zero printed on it for zero ohms. Removing this jumper will give you extended receive capability. Diagram (very bad but hopefully you get the idea)

This modification is read 885 times.
(IC-2GAT) Out-of-band transmit mod for IC-2GAT handheld 2M transceiver
Back side of display board: _____________________________________ I D505 I D507 D504 ___ I ___ ___ I___I I I I___I I___I -- + -I D506 Q506. I I I _o_-----_o_ J I hole for I I___I I I___I. I on/off-vol I o o I o o I control I I I I__________________ I -----K---------I I add diode: 1N914 or equiv. I I I
Connect diode between top lead of D506 and lower right lead of Q506 as shown. A surface mount diode may be added right of Q506 at J. note that the.___. are the same trace, while above the J is the center pole.o
. Note that this diode is 1906-0336, "-" at bottom, both "+" at top. ___|___ ^ ^ | |.
Notes: D506 may be absent. If not, remove it. Reset CPU if needed. A friend did this and his IC-2GAT can now transmit 138 to 178 MHz (no RF power output measurements were made). He did no retuning, and did not have to reset the CPU. He used a tiny axial-lead glass diode, replaced its leads with wire-wrap wire, and
encased it in shrink-tube. The operation requires a super-tiny soldering iron. Observe CMOS soldering precautions: Unplug the iron and ground the tip before touching the circuit. The 2GAT mod is really. Remove D 504 which is orginally a 1SS196 and replace it with a 1SS184 which is a dual diode. The service manual componet symbol shows the dual diode but lists the 196.
This modification is read 982 times.
(IC-2GAT) Step mods for IC-2GAT
To RESET the CPU (and wipe out memory), hold the LIGHT button AND the FUNCTION button while CPU is on, then turn it off, wait a second, and turn it back on. Continue holding the buttons while all the LCD segments display until "46.01" shows (about 12 seconds). This puts the radio into 5/10/15/20/25 khz step mode. Its starts in 15 khz steps and other steps in the list may be chosen. I wish 30 khz were in the list. The instructions for the IC-2GE are similar except that you hold down LIGHT and the WR button on top right next to the power switch. The IC-2GAT also performs this same reset, and also enters the 12.5/25 khz step mode. The step starts at 25 khz. When it is set to 12.5 (the only other choice until you reset the CPU the first way) you can dial up frequencies like 146.0125 which shows like "46.0125" where the "25" are BOTH smaller digits. The "5" never shows in the "American mode". The display goes to "46.01" in the "American mode" and to "46.00" in the European mode. Another curiosity is that when I RESET my CPU, I did so while it was tuned to 162.55 (weather). When I turned the power back on, EVERY segment was displayed, but the radio was actually receiving 162.55 anyway. Then when the reset finally took effect, the display went to "46.01" and the weather signal was lost. I also notice that sometimes, the "U" for synthesizer unlock (in the 10's position of the memory number) shows up just at the moment the "46.01" or "46.00" does, then ends in a second. I guess the sythesizer is being reset as well.

.-------------------------------------------------------------------l.------------DIODE-Da--------. l l D915 +-+ ['] D909 : l l.------------DIODE-Db--------+ l l D916 [ ] ['] D910 : l l. : l l D917 +-+ +-+ D911 : l l.----------------------------------------. : l l l.-----------. l : l l l.' '; l : l l l.' '; l : l l l : BACK OF : l : l l l : SPEAKER : l +--+ +-:+ l l l '.' l : : : ': l l l '.' l +--+ +--+ l l l ------------l l l l l +--+ +--+ l l l Removing this diode results in -----> l : --REMOVE-- : l l l expanded UHF coverage from l +--+ +--+ l '--------' 400 - 479 MHZ. l l l +--+ +--+ l l : : : : l l +--+ +--+ l l l l l l +--+ +--+ l Removing this diode results in -----> l : --REMOVE-- : l enabling the unit as a crossl +--+ +--+ l band repeater. l l l +--+ +--+ l l : --DIODE--- : l l +--+ +--+ l l l ------------------'

FIGURE 2

.------------------------------------. l.----------. l l : : l l : : l l : PA CHIP : l l : : l l : : l l '----------' l l.----. Attach V.O.M.----. l l : : meter lead --> O : : l l : () : : () : l l : : : : l l : : : : l l '----' '----' l l VHF VCO UHF VCO l '------------------------------------' Bottom
This modification is read 987 times.

(IC-32) IC-32E auf 9k6

Hallo, habe mein IC 32E erfolgreich umgebaut auf 9600BD. NF Ausgang vom IC 32E zum TNC an MAIN UNIT an IC707 TK1042M Pin 11. NF Eingang vom TNC zum IC 32E andie Leitung R779 nach R781 Signale UMOD VMOD. PTT an Stecker J710 Signal PTT. Fragen ueber Box DB0IZ oder Digi DB0END in 1200BD oder 0202/521349. Sowie ueber DB0IZ-9 in 9600BD Joerg aus Wuppertal DD8JM. PS: UMOD VMOD sind auch auf MAIN UNIT.
This modification is read 786 times.
(IC-32) IC-32AT Elimination of possible faint pulse noise
IC-32AT Amateur This service bulletin is meant for technical personnel with experience working on solid state communications equipment. Damage caused by improperly installing this modification may cause ICOM to charge for subsequent repairs to the product. ICOM does not warrant this modification. 13889-004 May 1, 1989 Elimination of possible faint pulse noise from speaker when radio is in power save mode The power save mode employs a circuit which creates a high level square wave signal used in the power save function. This modification alters the square wave characteristic to eliminate the noise.

Information:

Procedure 1. 2. 3. 4. 5. Remove the covers from the radio and locate the main board. Locate C-749 and replace it with a 2.2 uf 16 V tantalum chip capacitor. Reassemble the radio, power up and allow the unit to enter the power save mode. Check to see that the pulse type noise has been eliminated. Replace the covers and return the radio to service.

For those poor souls who are trying to use the ic-3200a on packet here is here is some relief. The problem is that when going from transmit to receive there is a delay in the receive audio turn on, which is on the order of 500 milliseconds and may be too long for some packet situations unless everyone had their txdelay set to 750 milliseconds. There are two ways to resolve the problem. Both are fairley simple. the easiest way is to remove the muting on the audio P.A. I.C. The instructions follow: 1. Remove the cover that has the speaker attached to it (being careful of the wires) 2. With T2. with the front of the radio facing you, look for the audio P.A. I.C. In audio P.A. I.C. in the right rear part of the radio next to the chassis it is marked "upc2002", looks like a to-220 case transistor, and has five leads on it 3. Immediately to the left of the "upc2002" is a diode standing on end, and marked "D19" on the circuit board this is the diode that mutes the audio P.A. I.C. during transmit 4. Cut one leg of "D19" and the audio P.A. I.C. will no longer be muted during transm ithis is all that is required and my tests have Shown that the ic-3200a will work with other tnc's with txdelay's set as short as 150 milliseconds where before this modification a txdelay of about 600 milliseconds was required of the station trying to communicate to the IC-3200A.
This modification is read 665 times.
(IC-3200) IC-3200A TX to RX delay fix
For those poor souls who are trying to use the ic-3200a on packet here is here is some relief. The problem is that when going from transmit to receive there is a delay in the receive audio turn on, which is on the order of 500 milliseconds and may be too long for some packet situations unless everyone had their txdelay set to 750 milliseconds. There are two ways to resolve the problem. both are fairley simple. the easiest way is to remove the muting on the audio P.A. I.C. The instructions follow: 1. Remove the cover that has the speaker attached to it (being careful of the wires) 2. WIth the front of the radio facing you, look for the audio P.A. I.C. In the right rear part of the radio next to the chassis it is marked "UPC2002", looks like a TO-220 case transistor, and has five leads on it 3. Immediately to the left of the "UPC2002" is a diode standing on end, and marked "D19" on the circuit board this is the diode that mutes the audio P.A. I.C. during transmit 4. Cut one leg of "D19" and the audio P.A. I.C. will no longer be muted during transmit and the receiver will respond almost immediately. This is all that is req'd and my tests have shown that the IC-3200A will work with other tnc's with txdelay's set as short as 150 msecs where before this modification a txdelay of about 600 msecs was required of the station trying to communicate to the IC3200A. For those interested in an alternate method here is what has been done by WB4FOW on several other radios: Since about 1985 most icom radios have pin 8 of the microphone connector wired to the speaker. This is convenient for the wiring of a tnc and is usually easy to modify so that receive audio is taken from the high side of the volume control. To get back to the subject of the alternate modification for the IC-3200A, you can rewire pin 8 of the microphone connector to the high side of the volume control and avoid the muting circuit but if you plan to leave the tnc wired permenantly to the radio and also,to use the radio on voice you will need to change a resistor in the tnc so as not to load down the audio at the volume control. the value of this resistor will have to be determined experimentaly. If anyone requires more information or assistance with this matter feel free to call clark, wb4fow, at 305-594-4313 monday through friday 10am to 6pm or leave a message in the w4nvu or aa4tm bbs's.

This modification is read 1070 times.

From: Chris

(IC-775) New product information IC-775DSP
Icom's new superior class HF transceiver the IC-775DSP is designed as a successor to the IC765. The IC775DSP offers high quality receive and transmit audio for serous DX'ers. In addition, a non-DSP type, the IC775, is also available. DSP (Digital Signal Processing; DSP-type only) DSP digitally transposes transmit and receive audio signals to produce desired AF frequenca characteristics and in addition performs the following functions:
Noise reduction - DSP converts all analog audio components to digital components, then seperates them into voice and noise at the digital stage. In this way, voice components can be singeld out and demodulated back to analog signals so that weak signals that would normally be drowned out by noise are audible. The reduction level can be adjusted to obtain the most desired audio characteristics. PSN modulation - PSN method (Phase Shift Network) generates SSB signals directly without DSB signals or SSB filters. Therefore even audio characteristics, over the entire range from low to high audio components, can be obtained, as well as high quality audio without filter group delays. Automatic notch filter - automatically suppresses the highest level beat signals in the audio frequency. Twin PBT - One of the more highly praised funtions of the IC-781 - twin PBT narrows the IF-passband in two stages to efficiently eliminate interfering signals. This function is especially useful during crowded band conditions such as pileups, contests, or for nets, etc. IF Notch - The IC-775's notch filter funtions at the IF stage, therefore, sharp and deep filter characteristics are obtained as with the IC-781. Automatic Notch (DSP-type only) - An automatic frequency adjusting notch filter ia available at the AF stage seperate from the IF notch. This automatic notch reduces the maximum beat level with no manual adjustment necessary. APF (Audio Peak Filter) - Allows a particular frequency to pass through at the AF stages. This function is convenient for CW operation. In addition, CW pitch is also related changed with APF. Dual Watch Funtions Dual watch monitors 2 frequencies on the same band simultaneously. Ideal for contests, traffic handling, DX chasing and net control work. To operate the dual watch, the IC-775 has two PLLs, two RF circuits and a balance control to balance signal strenght. Twin Tunning Knobs For convenient dual watch operation, the transceiver has two tuning knobs. The large main knob has good tension and response; the small, independent sub small knob can be used to watch a sub frequency. Newly designed PLL A new design is employed in the PLL circuit using ICOM's DDS technology and removing mixer circuits, resulting in higher quality C/N characteristics and superior spurious rejection. Power MOS FET's for clean signal. Superior 3rd, 5th, 7th IMD characteristics are oblaimed by power MOS FET's with high voltage. The IC-775 employs power MOS FETs in the pre-driver, driver and final amplifier stages, providing a clean 200 W of output over all bands.

This modification is read 703 times.

30-04-2000

(IC-821) IC-821H mods for extended TX/RX coverage:
Author: Fernando - Mederos-CX6DD-fmederos@adinet.com.uy.MODIFICATION.NET I have tested this on my IC-821H and it worked, needless to say I assume no responsibility for damage to your rig. D101 thru D108 are the relevant parts (diodes) and are located on the display board. You will have to remove both up and down covers and flip-down the front panel to gain access to the display board. 'Installing options' section of the user manual describes this procedure. D101 thru D108 are all SMD parts mounted near the center of the display board forming a single row, D101 being the one closest to the S-meter. Note that some diodes may be missing on the row, in my USA-version of IC-821 D101, D102, D106 and D108 were missing. Removing Removing Removing Removing D101 D103 D105 D107 extends extends extends extends VHF UHF VHF UHF RX (to 136-174MHz) (default for USA ver.) RX (to 420-460MHz) TX (to 136-174MHz) TX (to 420-460MHz)
There is no need for resetting to make this mods effective. Good luck!, Fernando Mederos-CX6DD-fmederos@adinet.com.uy.MODIFICATION.NET
This modification is read 940 times.
(IC-821) ICOM IC-821H - Frequenzerweiterung:
Oberen und unteren Gehusedeckel abschrauben, Frontplatte nach vorne herausklappen - mglichst waagrecht legen (?ber Tischkante hngen lassen oder Buch unterlegen). Neben dem Ausschnit f?r den VFO-Knopf werden die Dioden sichtbar: (Die Ansicht steht dann auf dem Kopf!)
-----------------------------------------------------------------------DISP UNIT OBEN _______ I I I I D108.. D101 x U U U U U U U U <<<< D102 bleibt f?r 1750 Hz <<<< Platz f?r 8 SMD-Dioden (best?ckt mit 5 Dioden)
I I I I I I I "VFO-" I I Knopf I I___________I
____________ IIIIIIIIIIII ------------
<<<<<< Stecker
UNTEN -----------------------------------------------------------------------Diese Dioden legen den Lnderkode und Frequenzbereiche fest: D________________________________ X X X X X X X X X X X X X X X X X X X X X X USA AUS EUR SWE Breitband mit 1750Hz (so war es)

This modification is read 1120 times.
(IC-W2A) IC-W2A Cross Band Repeat Function
To access the cross-band repeat function, first perform the extended receive mod by holding down the Light/B/# keys while turning on the power. To enable cross-band repeat, set each band to the frequency and mode desired. Set the current band to VHF. Press (Function-2) (Function-Enter) and the little "L" indicator will flash. The radio is now in the cross-band repeat mode. Do disable, press (Function-Enter) again.
This modification is read 947 times.
(IC-W2A) IC-W2A Extended Transmit Mod
Call the ICOM parts department ((206) 454-8155) and order a pair of MA133 diodes (P/N 1790000850). These are the three terminal surface mount diode packages. It is probably not advisable to substitute conventional leaded glass diodes here due to size restraints.
3 +--------+--------+ +-->|----->|--+ +-+-------------+-+ 1 2
The modification involves removing one surface mount component and installing two others. The working parts are extremely small and the mod should not be performed unless you are comfortable with working while using a loop eyepiece or other magnifying device. This is a "surgical" operation. Take all the usual precautions with respect to static electricity, etc. Remove 5 screws holding back on, and two screws on side of case below the PTT switch. Gently pry the unit apart. Inside the unit are two RF "stack" units. The complete RF "stack" is composed of two enclosed sheet metal boxes sandwiched
together, about 1.5" wide, 2" tall and.5" thick. Each RF stack unit (one per band) is totally self contained, is about.25" thick, and plugs into the "motherboard" using connectors mounted on one end. First, remove the stack units. To do this, remove one screw from each side of the stack. Remove the single screw off the bottom end of the stack and gently remove the metal spring clip holding the stack together. Carefully lift each stack unit out by pulling it back and down. They should easily unplug from the upper motherboard. Set them aside for now. At this time the back side of the front panel is clearly accessible and the two CPU's are visible side-by-side across the top. Now refer to the following illustration: Top of Radio, Back side of Front Panel

C231 C232 C234 C236 C237

from from from from from
1000 pf to 68 pf.01 uf to 1000 pf. (You can use the capacitor which used to be C231.) 100 pf to 22 pf. 47 pf to 22 pf. 680 pf to 100 pf. (You can use the capacitor which used to be C234.)
Solder a 10 microhenry inductor in parallel with L204, a 20 microhenry inductor. Changes for BS-8 Module I haven't tried the BS-8 module, but encourage you to try using it as is, without modification unless neces- sary. These steps are needed only if you cannot find settings of the side mounted aligment controls that get the display to behave as specified in the owner's manual: 1. Remove C233, the 33 pf disc capacitor, from the printed circuit board. 2. Replace coil L204, the 4.7 microhenry inductor, with a 6 or 7 microhenry inductor. Alignment Follow the alignment procedure in the SM-220 owner's manual to adjust the panadaptor. This consists of adjusting 2 potentiometers and 1 trimmer capacitor through holes thoughtfully provided in the side of the cabinet. The alignment instructions rely on the use of the internal Marker Generator to generate a signal at the center of the passband. If you haven't converted the Marker Generator circuit, you can tune your receiver to a frequency with a signal present at a known frequency (like 162.550 MHz - the National Weather Service), and use that as a frequency standard. Most of the time spent in aligment will be in alternate adjustments between the trimmer capacitor and the wide band sweep potentiometer, which interact with each other. Wider Bandwidth The SCAN WIDTH switch on the stock SM-220 can be set to display a 40 KHz or a 200 KHz wide picture. I adjusted my modified SM-220 to display a 100 KHz or a 500 KHz wide picture. By adjusting the controls on the side of the SM-220, wider bandwidths are possible, but wider bandwidths make it more difficult to resolve individual signals close to each other in frequency. As the bandwidth gets wider, the horizontal sweep loses linearity, causing the graticule calibration lines to be inaccurate. Connection to R-7000 As mentioned earlier, a DC voltage is present at the R-7000 IF output connector and is used to power an ICOM TV accessory. A direct connection between the R-7000 IF output connector and SM-220 would damage at least one of these units. To block the DC voltage, a 0.1 microfarad capacitor was soldered inside the R-7000, between the IF output jack and the adjacent jack labeled "spare". Connection between the R-7000 and SM-220 is then made using a short length of RG-58/U coaxial cable, with one end plugged into the R-7000 "spare" jack, and the other end plugged into the rear of the SM-220. This leaves the original IF output jack undisturbed so it can be used with the TV adaptor accessory. Vertical Sensitivity When I connected my modified SM-220 to my R7000, the SM-220 would display only the strongest of signals. To improve the display sensitivity, I inserted a 20 dB gain RF amplifier between the R7000 and SM-220. The amplifier was a spare Ameco PLF2 FET receiver preamp, adjusted for 10.7 MHz, but other amplifiers can be used, provided they have at least a 500 KHz bandwidth, and sufficient gain, at 10.7 MHz. False Readings - Images The SM-220 circuit is like a superheterodyne receiver. The panadaptor itself has a 455 KHz IF, and like other superheterodyne receivers with a low IF frequency, is prone to images. An image is manifested as a false pip, which moves across the screen as the receiver is tuned, and is 910 KHz (twice the IF) away from the actual signal. The images discussed here are in the SM-220, not in the receiver. Images are bothersome on the strongest sig- nals, like those 300 watt paging transmitters that saturate the county with RF, belching out out strange digital noises or voices (now illegal to monitor). Use With Other Receivers The modified SM-220 can be used with other receivers having a 10.7 MHz IF. In other receivers, one would need to find the

OPTION 2 CHANGES ARE IMPLEMENTED EXACTLY AS DISCUSSED IN THE PRECEDING TEXT EXCEPT THE "NARROW" FILTER SWITCH IS USED INSTEAD OF THE "BOTH SWITCHES IN" CONFIGURATION TO ACCESS THE ADDITIONAL BANDWIDTH. THIS OPTION MAY ONLY BE USED IF NO CW NARROW FILTER HAS BEEN INSTALLED IN THE RECEIVER.
A. Remove the top cover of the receiver. B. Turn ON the filter switch (S1) on the main PC board. S1 is a small slide switch not far from the center of the board. C. Locate D37 on the main PC board right next to IC3 near the center of the board. Cut the top (cathode) lead of the diode, leaving enough wire on both sides of the cut to make connections to. Bend the wire lead on the diode up. Solder a jumper wire from the cathode lead of D37 to the cathode (top) lead of D39 (located on the opposite side of IC3). D. PERFORM THIS STEP ONLY IF YOU WISH TO MAKE THE "IF-SHIFT" MODIFICATION FOR THE SSB/CW/RTTY "BOTH SWITCHES OUT" POSITION, AS DISCUSSED IN THE PREVIOUS TEXT. IF YOU ONLY WANT THE EXTRA AM BANDWIDTH, SKIP TO STEP "E." Cut the top (cathode) lead of D44, leaving enough wire on both sides of the cut to make connections to. Bend the wire lead on the diode up and solder a jumper wire from it to the top (cathode) lead of D42 (located near filter switch S1). E. Cut the top (cathode) lead of D46 (located a little toward the front of the main PC board). Make sure the two clipped leads are not touching. F. Locate D45 on the main PC board (near IC3). Cut the top (cathode) lead of the diode, leaving enough wire on both sides of the cut to make connections to. Bend the wire lead on the diode up. Solder a jumper wire from the cathode lead of D45 to the lead sticking out of the PC board which was clipped from D44. If step D was not performed, then solder the jumper to the cathode (top) lead of D44. G. Inspect your work and verify all steps were done properly. Make sure all tools are out of harm's way. Reconnect power, antenna and an external speaker, and test the modification. You should now have the following bandwidth settings:
AM wide. AM normal. SSB/CW/RTTY wide. SSB/CW/RTTY normal.. or SSB/CW/RTTY normal.. 6 KHz 2.8 KHz 2.8 KHz 2.4 KHz 2.3 KHz (CFW455IT) [no change] (FL-70/CFW455IT) (FL-70/CFW455IT) [no change] (FL-44A) [IF-shift, if step D was performed] (FL-30/FL-44A) [no change, if step D was not performed] (FL-30/FL-44A)

product review

Key Measurements Summary

0.13 0.14 75@10 MHz

ICOM IC-92AD Dual Band Handheld Transceiver
Reviewed by Gary Pearce, KN4AQ ARRL Contributing Author The IC-92AD came along pretty quickly as an addition to the IC-91AD, ICOMs flagship dual-display, D-STAR capable VHF-UHF handheld. The two models are so similar in form and function that you may wonder why there is an IC-92AD, and what justifies its higher price. Ill try to explain that. And since Dan Henderson, N1ND, reviewed the 91A model (without D-STAR) in December 2006 QST, Ill look at the digital capabilities of both the IC-91AD and IC-92AD.1 For more general information on D-STAR, see my article Operating D-STAR in September 2007 QST.2 Both the IC-91AD and IC-92AD are very full featured dual band (144 and 440 MHz) FM handhelds. They have lots of memories, wide receiver coverage (500 kHz to 1 GHz, except for the forbidden cell phone band), with receive modes for AM, FM and wide FM. The 91 series is D-STAR

SINAD 0.25

Receiver Sensitivity (12dB SINAD, V)
Henderson, N1ND, ICOM IC-91A Dual Band Handheld Transceiver, Product Review, QST, Dec 2006, pp 5961. QST Product Reviews are available on the Web at www.arrl. org/members-only/ prodrev/. 2G. Pearce, KN4AQ, Operating D-STAR, QST, Sep 2007, pp 30-33.
optional. The 92AD is available only with D-STAR built in. The IC-92AD exists to make emergency responders happy. It does that by having an optional GPS equipped speaker-mic. With that mic, in D-STAR digital mode, the radio can transmit the operators position with every voice transmission as part of the data stream. And it can be set to beacon a position report at adjustable intervals, similar to APRS. If you have a second GPS equipped 92AD, or a GPS equipped ICOM IC-2820H mobile, you can use that information to show a compass bearing and distance between the radios, right on the radios display Hes 2.8 miles that-a-way (Figure 1). Other D-STAR radio models can display the received coordinates numerically. The IC91AD can be connected to an external GPS, so the 92AD with the GPS mic just makes a neater, self-contained package. More on the GPS capabilities later in the article. The 92AD is also submersible (1 meter, 30 minutes). The Emcomm guys like that, too, but Ive heard a few hams scoff. One said that you perform emergency service after the hurricane, not during it, and you can buy a lot of umbrellas for the price difference. But an experience I had with another water resistant handheld came to mind. I had the radio on my belt at Disney World as my wife Cyndi, KD4ACW, and I got on one of those water rides. A sign warned: You will get wet. You may get soaked. We got soaked. That radio has never worked right since. So the 92AD has a couple of exclusives. Given the chance for a do-over, ICOM also took the opportunity to address a few issues hams had with the 91 series and made the IC-92AD a better package, with or without the GPS mic. As this is written, the 91 series is still available. You can decide if the IC-92ADs updates are worth the extra money.

I3 Rx 60@10 MHz

90 61@20 kHz*
Receiver 3rd-Order Dynamic Range (dB)

I3 Rx 40

61 65@20 kHz* 70

ChRej 50

Adjacent Channel Rejection (dB)

123 110

IF Rejection (dB)

Img 60

Image Rejection (dB)

Snd 100

252 266

Audio Output (mW)

T-R 250

50 2M 70 cm

Tx-Rx Turnaround Time (ms)

Off Scale

* Measurement noise limited

at value shown.

See www.arrl.org/members-only/prodrev, A New Look For Product Review.

Bottom Line

The IC-92AD is a very capable radio for analog and D-STAR digital VHF/UHF operation. Its expensive compared to analog-only dual-banders, and youll need to spend some time learning the digital features. In return, D-STAR offers many capabilities not available in the analog world. If youre into emcomm or search and rescue, check out the HM175GPS speaker/mic with a built-in GPS receiver.
One of These Things is Not Like the Other
Most reviewers like to see how much they can make a radio do before they crack the manual. Mark J. Wilson, K1RO

Product Review Editor

k1ro@arrl.org
From September 2008 QST ARRL
Can they turn it on, set a frequency, offset and tone, then key up a repeater and make a contact all without help? With the complexity of radios these days, thats not a given. Since I already had an IC-91AD, and the 92AD is very similar, my challenge was more like the Game of Seven Differences or the Sesame Street tune quoted in the heading for this paragraph. I went hunting for the changes. Most of the time, when I found one my reaction was, Yes, thats better. The very first thing I noticed was the VOLUME control, the outer ring on the dualcontrol shaft on the top of the radio. It rotates too easily on the 91AD, so its easy to bump too loud or soft. The IC-92ADs control is stiffer and has detents, so it stays in place. Ah, the humble VOLUME control. Todays diminutive dual display radios have a problem: not enough real estate on top for two VOLUME controls. One knob does double-duty, controlling both bands. That forces a choice. Do you control both bands at once? Do you only control the Main band? Each choice is a compromise. The 91AD and 92AD let you select either method, with options in the SET menu. The 92AD has another SET menu option labeled DIAL REPLACE. I saw that while playing the seven differences game, but didnt know what it meant until I read the manual. It lets you swap the functions of the center and ring knobs on that top shaft. This radio is nothing if not choices. Another example: Scan delays are adjustable from 2 to 20 seconds. The DIAL REPLACE mystery prompts me to mention that the display has a fine-grain dot matrix that permits lots of real English words in the various menus (see Figure 2). DIAL REPLACE may have stumped me, but SET MODE, SCAN, DUP/TONE, DISPLAY and SOUNDS are all pretty intuitive, at least if you speak basic ICOM. I can never remember some of the more obscure abbreviations of earlier radio menus what does 100 DT mean on my IC-W32A? And if you forget your reading glasses, the font size can be adjusted between large and small. My next observation was that the mic connector wasnt the usual two-pin affair. Its a round, multi-pin connector, covered with a heavy rubber cap. That connector is needed for the GPS/mic, and also handles all other data and programming connections to the radio. If you have an ICOM mic from an older radio, you can get an adapter cable. The rubber cap is a little hard to put in place once popped off. Its obviously there to maintain submersibility. The rubber plug covering the dc power connector is heavy duty, too. Physically, the 92AD is a little taller than the 91AD, and maybe a hair wider

Table 1 ICOM IC-92AD, serial number 0201019
Manufacturers Specifications
Frequency coverage: Receive, 0.495- 999.990 MHz (cell blocked); transmit, 144-148, 420-450 MHz. Modes: FM, AM (receive only), WFM (receive only), DV. Power requirements: 10-16 V dc or specified battery pack. Receive, 150 mA at rated output (single watch, FM), 38 mA (single watch FM power save), 220 mA (dual watch, FM/DV) with 7.4 volt battery pack. Transmit, 2.1 A (high power, 440 MHz), 0.4 A (lowest power, 144 MHz). Receiver AM Sensitivity: 10 dB S/N, 0.5-5 MHz, 1.3 V, 5-30 MHz, 0.56 V, 118-137 MHz, 0.5 V, 222-247 MHz, 0.79 V, 247-330 MHz, 1.0 V. FM sensitivity: 12 dB SINAD, 1.6-30 MHz, 0.4 V, 30-118 MHz, 0.25 V, 118-174 MHz, 0.14 V, 174-350, 470-600 MHz, 0.32 V, 350-470 MHz, 0.16 V, 600-999 MHz, 0.56 V; WFM, 76-108 MHz, 1 V, 175-222 MHz, 1.8 V; 470-770 MHz, 2.5 V. FM two-tone, third-order IMD dynamic range: Not specified. FM two-tone, second-order IMD dynamic range: Not specified. FM adjacent-channel rejection: Not specified. Spurious response: VHF, 60 dB; UHF, 50 dB. Squelch sensitivity: Not specified. Audio output: 200 mW at 10% THD into 8. Transmitter

Measured in ARRL Lab

Receive and transmit, as specified. As specified Receive (max vol, no signal), 180 mA; transmit (hi/med/low/s-low, with 8.2 V measured battery voltage), 144 MHz: 1.75/1.24/0.6/0.35 A; 440 MHz: 1.98/1.37/0.67/0.36 A.
Receiver Dynamic Testing 10 dB S+N/N, 1-kHz tone, 30% mod: 1, 3.9 MHz, 0.5 V; 14, 53 MHz, 0.34 V; 120, 146, 440 MHz, 0.42 V. For 12 dB SINAD, 29 MHz, 0.13 V; 52 MHz, 0.17 V; 146 MHz, 0.13 V; 222 MHz, 0.24 V; 440 MHz, 0.14 V; 902 MHz, 0.26 V; WFM, 100 MHz, 0.97 V. 20 kHz offset: 29 MHz, 60 dB*; 52 MHz, 59 dB; 146 MHz, 61 dB*, 222 MHz, 63 dB*; 440 MHz, 65 dB*; 902 MHz, 65 dB. 10 MHz offset: 146 MHz, 75 dB; 440 MHz, 60 dB. 146 MHz, 62 dB. 20 kHz offset: 29 MHz, 60 dB; 52 MHz, 57 dB; 146 MHz, 61 dB; 222 MHz, 60 dB; 440 MHz, 65 dB; 902 MHz, 54 dB. IF rejection, 52 MHz, 22 dB; 146 MHz, 121 dB; 440 MHz, 123 dB; 902 MHz, 110 dB; Image rejection, 52 MHz, 79 dB; 146 MHz, 88 dB; 440 MHz, 75 dB; 902 MHz, 2 dB. At threshold, VHF, 0.1 V; UHF, 0.13 V. 320 mW at 10% THD into 8. Transmitter Dynamic Testing
Power output: VHF and UHF, With battery pack or external 13.8 V dc, 5.0/2.5/0.5/0.1 W. VHF, 5.3/2.8/0.5 /0.1 W; UHF, 5.0/2.8/0.5/0.06 W; Spurious signal and harmonic suppression: VHF, 66 dB; UHF, >70 dB. 60 dB Meets FCC requirements. Transmit-receive turnaround time (PTT release Squelch on, S9 signal, VHF, 252 ms, to 50% of full audio output): Not specified. UHF, 266 ms. Receive-transmit turnaround time (tx delay): VHF, 74 ms; UHF, 77 ms. Not specified. Size (height, width, depth): 4.4 2.3 1.3 inches; weight, 11.5 ounces. Price: IC-92AD, $580; HM-175GPS speaker/mic, $350; RS-92 software and cable, $70. BP-256 battery pack (7.4 V, 1620 mAh Li-ion) and BC-167 wall charger (approx 6 hour recharge time) supplied. Available options: Replacement BP-256, $75. BC-177 desktop drop-in rapid charger (2.5 hours), $60; BP-257 battery case (2 AA cells, TX power limited to 100 mW), $30; CP-12L ($36) and CP-19R ($44) cigarette lighter cables; OPC-254L external power cable, $14. *Measurement was noise limited at the value shown.

and thicker. Even so, several hams who held it said they liked the feel of the newer model. Another change is the belt clip. The IC-91AD has a very stiff, single-piece steel clip. The 92AD has a lever with a hook at the bottom that I find easier to clip to my
belt single-handed. All these discoveries came while the radio was addressing its A side. I tried to switch to the B side. Couldnt do it. ICOM swapped the functions of three main front panel buttons, but my fingers had muscle
memory from the 91AD. Reading the labels on the 92AD solved my problem, still without resorting to the manual. After reaching the B side, I tried DV (Digital Voice) mode to key up the local D-STAR repeater. The 91AD and 92AD do digital only on the B side of the radio (they do analog on both sides). I programmed the key call sign fields needed for local repeater use (see Figure 3; this procedure is described in more detail later). But I got nothing. Stock-from-ICOM D-STAR repeaters dont have hang-time or a courtesy beep, so it can be hard to tell if youve keyed it up. I was listening on my ID-800H base station, so Id hear myself and I didnt. There are a lot of DV settings, but I was pretty sure things were right. I looked harder at the main display and noticed the tiny legend SLO in the corner. Hmmm. SLO. Slow? Something prompted me to push (and hold) the output power button. The legend changed to LOW. Okay, its the power indicator. Another push brought MID, and another brought a blank spot (for HIGH).
Figure 1 The GPS compass display shows that the last reported position of the received station is 12.5 miles NorthNortheast, and gives the exact latitude and longitude. As this radio moves, the direction and distance to the last received report is continuously updated.
had enough juice left for a finger-frying test of the adjustable time-out timer (set for three minutes) at 5 W before the battery indicator dropped the first of its two bars. Switching down to 2.5 W brought that bar back for many more minutes of transmitting. I never managed to kill the battery. I plugged in the charger and ticked off another little upgrade: a big CHARGING indicator on the display. The 91AD just flashes the tiny battery icon when charging.
Audio Reports and Memories
On the air, I asked for audio reports in both analog and digital. The first analog report was very natural sounds like you. But other reports werent so flattering, especially when I offered a comparison with the 91AD and my IC-2820H mobile. The 91AD had better fidelity, with more lows and highs. The 2820H rolled off the low end and was very sharp, giving it marks for most readable. The 92AD seemed somewhat restricted, right in the middle of the vocal spectrum. Ive heard a couple of other IC-92ADs on the air, and they sounded okay to me. Ive made recordings of all three radios, in both analog and digital mode, recorded directly from the speaker jack of my ID800H into my computer line input. You can judge for yourself by listening to the audio file, available for download from the ARRLWeb binaries page.3 The receive audio was reasonable for a handheld. Ive seen complaints that the volume isnt loud enough, but I could hear it just fine in a car with open windows at highway speeds. I dont know what more you could ask. Next it was time to fill up some memories with local repeaters. ICOM offers optional software and an interface cable for this, but it didnt come with the review radio so I did it manually. The big display makes this easy. It presents your options for naming and storing the memory all on the same screen (Figure 4). Tone settings are buried in another menu. And remember when turning tone on and off was simple? Now pressing the TONE button brings an endless series of options. Heres a secret: hold the TONE button and turn the top knob to move quickly forward and backward through the options. An UP/DOWN , LEFT/RIGHT rocker switch is embedded in the keypad for navigation through the menus. That finegrain display lets you name your memory channels with eight characters, including upper and lower case text, numbers and lots of special characters. With the radio set for single-band display, it shows both the

3www.arrl.org/files/qst-binaries.

The 2.5 W Sweet Spot

The IC-92AD has four power levels 100 mW (SLO), 500 mW, 2.5 W and 5 W. The 91AD has just the 500 mW and 5 W levels. The new radios extra power levels address two complaints about the IC-91AD: battery life and heat. On longer transmissions at 5 W, both radios get pretty hot and uncomfortable to hold. They should. Theyre dissipating about 4 W, the same as one of those old, big Christmas tree light bulbs. Try wrapping your hand around one of them for a minute! The manual warns you about it (the radios heat, not the Christmas light). Both radios use lithium-ion batteries that seem to give other handhelds nearly indefinite life, but the 91AD appears to chew up its battery quickly. The IC-92AD has a somewhat higher capacity battery and marginally lower current drain. The big advantage for battery life is that 2.5 W MID power setting. Its just 3 dB down from 5 W and not very noticeable in FM (a slightly noisy signal will get a little noisier). Its not noticeable at all in DV, where signals stay full quieting until theyre almost gone, unless youre right at that minimum signal threshold. At 2.5 W, current drain drops significantly (see Table 1). The radio gets warm, but not hot, with long transmissions. The batteries for the 91AD and 92AD are slightly different sizes so, alas, they cant share batteries or drop-in chargers. I was successful in keying up the repeater once I raised power. My call sign and the short message Id programmed with my name and the radio model number scrolled
Figure 2 The large display and fine dotmatrix pattern allow longer words, many in something like real English.
Figure 3 These four key call sign fields (YOUR, RPT1, RPT2 and MY) are the heart of D-STAR repeater operation and routing through the Internet.
Figure 4 The display shows many of the memory channel parameters on one screen.
across my base station display. D-STAR digital sends that information with each transmission, right along with your voice. I kept the IC-92AD turned on from 7 AM to near midnight several times, with a few short ragchews at 2.5 W, a little more listening, but mostly squelched receive. It

list is shared with other Gateways. Thats part of what MYCALL is for. So if I plug your call in to my radios YOUR field, my local repeater plays another game a D-STAR version of Wheres Waldo? It looks at its list to see what repeater, anywhere on the network, anywhere in the world, you keyed up last. Then it instantly routes my transmission to that repeater. I can also put a specific repeaters call sign in the YOUR field to manually route my transmission to that repeater. In that case, Id need to precede the call sign with a / that says this is a repeater call. And Id need to include the port letter, which Ill explain next. The middle two fields shown in Figure 3 are RPT1 and RPT2. RPT1 is almost always the call sign of the local repeater. In this example, its KI4WXS in Charlotte. But notice the B hanging out there on the end. Thats the port letter. ICOM has D-STAR repeaters for 144, 440 and 1200 MHz, and many installations have all three bands. They all share a single call sign. Since transmissions are routed by call sign, I need to enter the extra letter to specify which repeater I want my signal to reach. The convention is A for 1200 MHz, B for 440 MHz and C for 144 MHz. The RPT2 field in Figure 3 shows KI4WXS G. The G stands for Gateway. The current recommendation is that I leave the Gateway call sign in RPT2 pretty much all the time. When D-STAR first arrived, ICOM said to set that Lets Do Digital to Not Use if you werent going to actually Now Im going to tax your ability Figure 5 The HM-175GPS speaker/mic includes a GPS use the Gateway. Youll see that in the to absorb new stuff. The details of receiver, making a self-contained package. Its big, as manual. Thats changed, primarily D-STAR programming arent easy shown here with a more conventional speaker/mic. to support use of a device called the to grasp at first. I interviewed several DV Dongle, which lets hams access of the hams at the leading edge of D-STAR repeaters from their home D-STAR for my video documentary Digital call sign if I want to talk to you. For routine, computers over the Internet. Dongle users Voice for Amateur Radio.4 I asked each of local operation on repeaters or simplex, that (get over it, thats the name) can only hear them to demonstrate how to program a radio field holds CQCQCQ, but there are circum- stations that have the Gateway addressed for the various D-STAR functions. Doing stances in which Id put your individual call in RPT2. this off the cuff, each of my experts made sign. One example is call sign squelch. You Now, if you think about it, youve got the a mistake in one detail or another. What can tell your D-STAR radio that you only potential for a lot of call sign programming. chance do we mere mortals have? want to hear transmissions directed spe- as you route your signal to specific hams Lets all take a deep breath and give it a cifically to you a very personal squelch around the world. Fortunately, the memory try. Im only going to touch the basics. This control. So to open your speaker, I put your channels store the YOUR, RPT1 and RPT2 is a review, not an instruction manual. But call sign in the YOUR field. Neat trick. fields along with the usual frequency, offset, I am planning on producing a short, new If youll bear with me, Ill push that tone and mode. So for every combination of video that concentrates on D-STAR radio YOUR example a little further. D-STAR local repeater, distant repeater, and friends programming. The one will be free, hosted is a network of repeaters, linked by the call sign, you use a memory channel. Youll on YouTube, and it should be ready by the Internet through Gateways Linux based need to get creative in naming those chantime this review is printed. Check my Web computers running at the repeater sites. The nels. By the way, to use a Gateway, you have Gateway keeps a list of all the users who 4S.Ford,WB8IMY, ShortTakes Amateur have keyed up the repeater recently, and the to be registered. Thats done locally, through Radio Video News, QST, August 2008, p 64.

frequency and your memory name. In dualdisplay, you choose one or the other. Programming is easy, but with 800 memory channels on the A side, 400 more on the B side (the A and B sides are separate they dont share memory channels), and 24 more scan-limit pairs on each side, its going to take some time. Memory channels are especially useful for D-STAR, which Ill explain in a minute. So the software is a good investment. There is no national simplex channel for D-STAR, as 146.52 MHz is for FM voice. The D-STAR community is discussing the options, and the leading contender is 145.67, but that is used for conventional packet in some areas. The UHF discussion hasnt even gotten that far. Back to memory programming the BANK NAME doesnt refer to the financial institution from which you obtained a loan to buy the radio (if you loaded it up with the GPS mic, software, cables, a rapid charger and extra battery, you crossed the $1000 mark a while ago). With that many memories, you need a second level of management. Both the 91AD and 92AD have 26 memory banks, labeled A through Z. Each bank holds 100 channels. You can cherrypick individual memory channels and place them in banks. When you select a bank, youre limiting the radio to the 100 or fewer memories in that bank for scanning or manual tuning.
site www.ARVideoNews.com. To describe programming, Im going to shift perspective and write mostly in the first-person I do something with my call sign. Thats because the nomenclature of ICOMs programming is from that perspective. My call is KN4AQ. Your call is well, you know what your call is. Heres the key D-STAR operation is based on call signs. There are four call sign fields in every D-STAR radio. What I put in those fields controls where my signal is heard. The 91AD and 92AD present these four fields together on one screen labeled CALL SIGN (see Figure 3). The bottom field, MY, gets my call sign, KN4AQ, as long as Im using the radio. If I hand the radio to my wife, she switches it to KD4ACW. The top field, YOUR, is where I put your

and show up on the compass your repeaters Gateway Addisplay that shows the direction ministrator. Youll be able to and distance between radios track him or her down through (see Figure 1). And that was dstarusers.org. very cool. I was following Ken, There is news on the GateKC4YOZ, up to the Charlotte way front. Until recently, weve D-STAR repeater site, and we all said that you cant link regot far enough apart that I could peaters in D-STAR in the same read his bearing and distance. way as IRLP and Echolink If GPS has you thinking all network communication APRS, Ill warn you that Dwas between individuals. Now STAR data is not on-air comyou can, two different ways. patible with AX.25 packet ICOMs G2 Gateway software data. Theyre both digital, but now permits connections bethe similarity ends there. The tween as many as 10 individual 91AD and 92AD do have repeaters. The Administrator D-STARs low speed data sets up the conference and Figure 6 My position, course and speed, as reported on FindU.com, courtesy of the Dplus program running on the capability. A 1200 bps data users must put a conference Charlotte D-STAR Gateway. signal rides along with every name in the YOUR field. And voice transmission. You need a the third-party Dplus program lets the Administrator connect the repeater only after receiving an EMR transmission computer and another optional cable to use to a conference server. Users dont have to with my volume up once was I able to then it theres no access to this data via the do anything special. Everyone on all the hear them with my volume down. After that, radios controls or display. There are several conferenced repeaters hears everyone else. EMR worked every time. Try this before third-party programs already available for using this data stream for text messages That wasnt so hard, was it? Weve still you rely on it! and small file transfers, and more on the got to cover two more features, and that GPS GPS on D-STAR way. Again, this data is not AX.25 packet microphone. The IC-92ADs GPS speaker-mic (HM- compatible. Turn Up the Volume! 175GPS) shown in Figure 5 comes with There is a bridge between D-STAR and The last two features Ill describe are the built-in sticker shock. Were not used to the APRS networks. A third-party applicaBreak-In and Emergency modes, common paying $350 or more for a speaker/mic, but tion called Dplus runs on the Gateway. It to the 91AD and 92AD handhelds, and the of course this one has a GPS receiver and can pick off your GPS data and forward it it plugs conveniently into the radio with no to the APRS network via the Internet. Your ID-800H and IC-2820H mobiles. location shows up on APRS displays, and These transmit modes allow you to be adapter or power cables. The mic is large and heavy for a hand- on Internet sites like Find-U (see Figure heard by D-STAR stations who are using any of the various forms of selective squelch held. Itll tug hard at the collar of your shirt 6). The manual falls short here. I was suc(call sign squelch, which I described earlier, if you clip it there. And GPS is its only trick. cessful using instructions supplied by Ken, and Digital Code Squelch (DCS), which There are no up/down buttons or volume KC4YOZ. I suggest contacting your local is similar to analogs CTCSS). Just turn control. You might expect some extras D-STAR experts. on BREAK-IN with a keypad button on the for the price, but this mic is designed for IC-91AD, or in a menu on the 92AD, and emergency responders in the field, so KISS In Conclusion The IC-92AD is a very capable, complete everyone on the channel hears you, regard- applies. It has one illuminated yellow button to turn the GPS on and off. That button radio for analog and digital VHF/UHF opless of their squelch settings. lights up while the GPS is acquiring satellite eration. The only significant downsides I Emergency mode is even cooler. What do you do when a conversation on signals and blinks when it has a lock. Under found are the mediocre transmit audio, the the radio interrupts something youre doing open sky, it took about a minute to lock. It price and the complexity (youll need some a phone call, writing an article on your took longer but did get a lock indoors in local help to get the most out if this radio). If youre into emcomm or search and rescue, computer, sleeping? You turn the volume some single-story, wood-frame buildings. I turned to the manual (for the first time!) the GPS mic is a great addition. down. And there it sits until you remember Manufacturer: ICOM America, 2380 to turn it up again. If I activate EMERGENCY before trying to use the GPS function. I understood the instructions up to the point 116th Ave NE, Bellevue, WA 98004; tel 800MODE (again, keypad on the 91AD, menu on the 92AD), I can reach into your radio of telling me to plug in the mic. Then it lost 872-4266; www.icomamerica.com. me under the heading Sentence formatand turn your volume back up! I felt a little strange as I experimented ter setting. While ICOMs manuals are with this, almost like I was dialing 911 just usually above average, they all fall short to see if it worked. Only problem was, it in explaining general D-STAR operation. didnt work! I tried all four of my D-STAR Without some prior knowledge, they leave radios. I turned their volume down, then you hanging. I gleaned enough from the manual to transmitted to them with a radio in EMR. They stayed quiet. The manual was just as let me poke around the menus and get the silent, referring to the specified volume GPS functions turned on in both the 92AD level without telling me how to specify handheld and my IC-2820 mobile. It turns that level (or even who specifies it, because out that you need very little from the manual apparently it isnt me). I experimented, and to get GPS data to flow between these radios