(IC-271) (IC-271) (IC-271) (IC-2710) (IC-2710) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-275) (IC-28) (IC-28) (IC-2800) (IC-2800) (IC-2800) (IC-2800) (IC-2800) (IC-2800) (IC-2800) (IC-2800) (IC-2800) (IC-2800) (IC-281) (IC-281) (IC-281) (IC-2AT) (IC-2AT) (IC-2GAT) (IC-2GAT) (IC-2GAT) (IC-2GAT) (IC-2GXAT) (IC-2GXAT) (IC-2IA) (IC-2IA) (IC-2IA)
IC-271 / 471 fuer 9k6 German language IC-271 sounds raspy in SSB/CW English language RAM Card Backup Battery Replacement Instructions English language Some modification for IC-2710 English language Crossband Repeater Operation for the IC-2710 English language PSK Transmit Audio Modification for ICOM IC275 & IC271 English language IC-275 Freq. steps mod. English language Band Expand for ICOM IC-275E/H and IC-275A/H English language IC amplifier oscillates English language Prevent PLL unlock at high ambient temperature English language Improve voice synthesizer and side tone audio English language Prevention of PLL unlock at 174 MHz English language Improve the stability of the center meter English language Noise coming from speaker during transmit with audio turned up English language Eliminate possible spurious emission when thermal switch has turned on during TX English language Frequency range & CTCSS tones English language Power control modification English language Restoration of pass band tuning 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 Splitting into RX- and TX paths English language ICOM IC-28A AND IC-28H ext frq English language The long, noisy squelch-tail of the Icom IC-28 English language Icom IC-2800h Extended RX Mod English language Icom IC-2800 Extended RX/TX Mod English language Icom IC-2800 Extended RX/TX Mod, Australian model English language IC-2800/HM98 tx-audio mod English language sensitivity ICOM IC-2800H English language IC-2800H cross band mode operation English language DTMF options card English language Screen saver Turn OFF option for IC-2800 English language Cross Band Repeat for IC-2800 English language Enable crossband function for IC-2800 English language Crossband repeat English language Extended Receive for IC-281 English language Extended Transmit for IC-281 English language Coverage IC-2AT 140-150 MHz English language Operation and L3 ADJUSTMENT English language Out-of-band transmit mod for IC-2GAT handheld 2M transceiver English language Step mods for IC-2GAT English language IC-2GAT to packet English language ICOM IC-A20 alkaline headset-adapter lost-in-the-soup English language The ICOM 2GXAT HARDWARE MOD English language Software mod, to open IC-2GXAT English language IC-2Ia mic mods English language IC-2IA lousey xmit audio fix English language IC-2IA mod. English language

31-01-2000

(AH-4) Icom, AH-4, AH-3 ( automatic antenna tuner ) connection to any radio.
Author: AA7OL Niko Takahashi - aa7ol@hotmail.com.MODIFICATION.NET
Icom AH-4 and AH-3 ( automatic antenna tuner ) connection to any radio
Both AH-3 and AH-4 are similar Here is a redesign of connection digram of the ICOM IC-AH3 and IC-AH4 by 5B4AEZ.
There is four wire control cable coming out beside coax cable. Control cable has White: Start tuning Green: Tuning in process RED: 12 V DC input Black: GND
Tuning Process 1. Put about 10 watts of power into tuner. ( CW )
2. After about 0.5 second, press start switch for a moment. ( use momentary contact switch ) 3. LED start blinking , which indicate tuning is in process. 4. After about 3 seconds or so, LED shut off, and tuning is completed, If tuning is successful SWR should be less than 1.2
Some radio start to reduce the power when SWR is high, this tuner takes at least 10 watts of power for tuner to work properly. Most of the 100 watts radio should not have any problem, since they still put out 10 watts or so, even with high SWR. But, it does not work with some QRP radio ( 5 watts or less ). Adjust power level, if necessary. You may extend control cable to 100 feet , it still work fine, you can put this tuner on top of tower. Let me know , how it worked aa7ol@hotmail.com.MODIFICATION.NET
This modification is read 1503 times.

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07-06-2001
(AT-160) Using the AT-160 with the IC-706MKII
Author: Dave Abshire Sr. - KG4KOX - KG4KOX@aol.com.MODIFICATION.NET
ICOM's IC-706MKII transceiver and AT-180 antenna tuner are designed to work together. However, ICOM's AT-160 is a very popular antenna tuner. Originally designed to work with the IC-728 and IC-729 transceivers (now out of production), the AT-160 will work with the IC-706MKII if the following instructions are followed: 1. (IC-706MKII only, not IC-706) The IC-706MKII will transmit on VHF constantly when connected to the AT-160. To stop this, remove the wire attached to pin 6 of the DIN connector within the OPC-104 cable. 2. Open the AT-160 and make sure the switch labelled "S1" on the circuit board is switched to the bottom, shown as "IC725/726" in the AT-160 instructions. 3. Make sure that the connections to the AT-160, using the OPC-319, OPC-104, or OPC-125C cables, are according to the AT160 instruction manual. ICOM America suggests using the OPC-599 adapter cable for connection of the OPC-104 to the IC706MKII. 4. Connect the radio to the transmitter terminal and connect an antenna to the ANT terminal. Make sure the antenna has less than a 3:1 SWR. Place the radio in FM, AM or RTTY mode and key the mic. The AT-160 will now tune properly. 5. The tuning button on the front of the IC-706MKII will not operate when using the AT-160 antenna tuner. This feature was designed to work with the AT-180. 6. Check the SWR presented to the radio. It should be less than 1.5:1. The AT-160 operates with the IC-706MKII as it would with the IC-725 or 726 transceivers. Included with the AT-160 instructions is a page dedicated to the antenna tuner's operation with an IC-725 and IC-726 transceiver. This is not the way the AT-160 operates with the IC-706MKII. 7. There is no way to turn the AT-160 off or place it into "thru" mode when operating with the IC-706MKII.

This modification is read 822 times.
(I290) Icom I290 scan modification
The objective of the modification is to implement a delay before scanning restarts when, in SCAN-STOP mode on BUSY frequency, the received signal disappears. The modification will then allow a frequency to be free for a while before scanning resumes. With this modification, it will be given a chance to a signal to come back within a few seconds before the scanning restarts. Now multiple QSOs or poor signals won't be truncated any more because of a too much impatient scanning ! WHAT TO DO: Very simple. On the SENSOR UNIT, just solder a jumper between:
the unused contact of switch S3 (the one corresponding to the TIMER OFF position of the circuit commanding the SEL pin of IC1) and the EMPTY signal of connector J3 (this is the extreme pin nearest S2 on the SENSOR unit)
ATTENTION, there are some errors on the electrical scheme that I possess reference A-0488 :
The S3 switch is represented in position TIMER OFF and not ON as written. You have to reverse labels OFF and ON. The signals BUSY and EMPTY on connected are reversed. EMPTY (SQ1) is on the extreme left pin of S3 and BUSY is on 2nd pin of this connector S3. In fact, the switch S2 is drawn in the BUSY position and not EMPTY.
HOW IT WORKS : The TIMER starts when pin SEL of IC1 goes to 0V. When the TIMER is running, the scanning is halted. The scanning also stops when the BUSY signal is low level (0V) on pin SQL of IC1. Let us suppose that a signal is received. Then BUSY goes to 0V and scanning halts. At the same time the EMPTY signal , which is the inverse of BUSY, goes to 5V and the TIMER remains off. If the received signal disappears BUSY goes high and EMPTY low, then the TIMER is enabled and starts running. It also maintains the scanning in halt mode. If, at the end of the TIMER delay, no signal has come back then the scanning restarts. If a signal comes back before the end of the TIMER delay then the BUSY signal returns to 0V and maintains the scanning in halt mode. In the meantime the TIMER will run until the end of its delay without any action on the process. The TIMER delay is chosen with the R32 potentiometer on the SENSOR UNIT. The minimum value is about 4 to 5 seconds which is perfect for this working mode. Small modification. great effect ! Gabriel F6DQM @ FF6PTT.FRPA.FRA.EU
This modification is read 407 times.
(IC-02) Band expansion modification for IC-02AT
FOR SERIAL NUMBERS ABOVE 34000 BY LTC STEVE PETERS, CAP 1. Remove back from radio (5 screws) and bottom plate (4 screws). 2. Carefully remove radio chassis from front case by pulling out top of radio and lifting slightly (to remove battery contacts from bottom case). Be extremely careful of ribbon cable and heat sink compound on power amplifier module. 3. Remove diode D2 from matrix board. 4. Add diode D4 (any small diode 1N4148; 1SS211 5. The following is a schematic of the matrix board:

(IC-271) IC-271 / 471 fuer 9k6
es kommen doch noch anfragen wie man die 271/471/(1271?) geraete von icom fuer 9600bd umbaut. hier nochmal allgemein: fuer den empfang geht man an den pin 9 des ics MC3357 auf dem main-board. fuer die rx seite wars das schon. fuer tx verfolgt man den weg vom evtl. vorhandenen tone-unit zum main-board. dort sollte die leitung ueber einen widerstand an eine varicap-diode gehen. das ist auch der punkt an dem man das modem anschliessen muss. es ist sehr ratsam direkt an die diode eine ferritperle mit einer windung anzuloeten, und dann erst auf das g3ruh modem zu gehen. (gleichniss "pferde vor der apotheke" HI) das wars auch schon. diese allgemeine umbauanleitung kann fuer die 271er und 471er geraete (a/e/h) benutzt werden. danach haben einige andere oms auch ihre geraete umgebaut. (ihr solltet erstmal meine englische anleitung lesen HI) hier jetzt speziell fuer den 471h. fuer den empfang braucht man nur eine 2pol. stecker(weibl) den man auf den j-14 (der bei mir unbenutzt war), auf dem mainunit, aufsteckt. fuer den sendezweig geht man mit dem signal, auch auf dem main-unit, am besten an die kapazitaetsdiode d4. und zwar an den knotenpunkt r271-c18-d4-c17. die zuleitung sollte mit einer ferritperle abgeblockt sein. ich hoffe mit diesem schaltungsvorschlag konnte ich jemandem helfen. vy 73 de detlef dd1eg p.s. dieses geraet benutze ich auch um via uosat-d qrv zu sein.
This modification is read 676 times.
(IC-271) IC-271 sounds raspy in SSB/CW
05-08-1998 Hello dear OM, thanks for reading this bulletin. I have an Icom IC-271 since several years. Recently the sound in SSB or in CW sometimes becomes raspy, both in TX as well as in RX. The problem is intermittent and also the 'raspyness' varies. I already found some hints at the Icom America website, where they describe a similar problem. They advise to replace electrolytic capacitor C2 and replace 2 plastic trimmer caps by ceramic ones. I tried this, but it did not cure the problem. Is there anyone out there who has had this problem and knows the solution? Please send me a reply or send an email to amunters@xs4all.nl Thanks in advance, 73 de Allard PE1NWL Amsterdam, Netherlands
This modification is read 733 times.
(IC-271) RAM Card Backup Battery Replacement Instructions
Author: ICOM In the early 1980s Icom America marketed a group of transceivers and radios that utilized the latest state-of-the-art computer technology to enhance the operation of the radios. This technology improvement allowed hams to afford a reasonably priced high performance transceiver which until then was only available on units costing much more. Features now available to the hams included: higher frequency stability, better frequency resolution, digital frequency display, almost instant recall of saved frequencies (memory channels), quick mode signal processing and built in tones and offsets for the rapidly emerging repeater operation. Implementation of all these features required a CPU with associated logic circuitry. In the early 80s, the most cost effective way

(IC-2710) Some modification for IC-2710
Maximum supported frequency range:
VHF, 118-135.995 MHZ RX, 136-174 MHZ TX & RX UHF, 320-399.995 MHz RX, 400-479 MHz TX & RX UHF, 849-869 MHZ & 894-950 MHz RX
See product literature for frequency limits from factory. Please note, these are the "tunable" frequency ranges only. The receivers are optimized over 20-30 MHz ranges which have been centered around the ham bands at the factory. Performance outaide the ranges defined in the product specification is not guaranteed. AM/FM mode selection (118-135.995 MHz or 320-399.995 MHz RX only:
Select an appropriate frequency (left side display only) Push and hold the left side MONI(SQL) switch for about ONE second to toggle AM mode ON or OFF. The symbol "<" appears to the right of the frequency when AM mode is enabled
Frequency range modification:
Remove Power and Antenna Leads remove the bottom cover of the radio (See section 16, Page 65 of instruction manual). Viewing the bottom of the radio, orient the chassis with the fan to the right (front of radio to the left) refer to the drawing and locate the identified components on the main board in the lower left of the radio
To ennable receive on all supported frequencies:
Cut jumper "W-18"
To enable only some RX frequencies:
Remove "D-134" to enable receive on 300 & 800 MHz frequencies, or Remove "D-132" to enable receive only 300 MHz frequencies
To enable extended transmit ranges:
For extended VHF TX range, remove "D-135" For entended UHF TX range, remove "D-136"
This modification is read 1166 times.

12-11-2000

(IC-2710) Crossband Repeater Operation for the IC-2710
Author: Kevin - Kastle@aol.com.MODIFICATION.NET
Cross Band Repeater Mode:
First, verify D-139 is not present (for non USA Versions only)
To ENTER Cross Band Mode:
Set the desired frquency, tone, & offset on both bands Press [VHF} and [UHF] main knobs and the [SET L] key at the same time (An "L" will appear on the display) For zero hang time, also press the [LOW] key with the above three key command.

To EXIT Cross Band Mode:

Press [SET] to exit Cross Band Mode
Remote Operation (UT-49 DTMF Decoder Unit Required for Remote Operation) 1. Set the sub band frequency to receive a control signal (DTMF code). q The optional tone squelch function can be used for the sub band to increase remote control reliability. Password Setup 2. Program a 3-digit password into the sub band's code channel 5, if desired: (default is 000) a. Push the desired band's tuning dial. *Each band has separate code channels. b. Push [DTMF] 2 times to turn the pager function ON. * "P" appears in place of the 100MHz digit. c. Push {(VOL)SET] to select the code channel setting display. d. Rotate the selected band's tuning dial to select the desired code channel, 0-5. * Code channel P cannot be used for programming. e. Push [(SQL)MONI] or [(VOL)SET] to select the digit to be programmed. f. Rotate the selected band's tuning dial to set the digit. g. Repeat e and f until the last digit is programmed. h. Push [DTMF] to set the code channel for "receive inhibit" or "receive accept." * When "receive inhibit" is set, "SKIP" APPEARS. * Code channel 0 cannot be set as "receive inhibit." i. Push the selected band's tuning dial to exit the setting display Remote Operation Continued (UT-49 DTMF Decoder Unit Required for Remote Operation) 3. Select the main band by pushing a tuning dial, then set the desired frequency for operation. 4. Push [DTMF] one or more times unil "REMO" appears to select standby for the remote control. 5. Set the operating frequency of the controller transceiver equal to the sub band frequency of the the IC-2710H. * Make sure a tone frequency is set when using the optional tone squelch function with the IC-2710H. * The external DTMF remote does not accept a control signal on the main band frequency. 6. From the controller transceiver, transmit the DTMF code as follows:

This modification is read 3237 times.

From: Roy Rodgers

17-07-1999
(IC-2800) Icom IC-2800 Extended RX/TX Mod, Australian model
Hi all you lucky IC-2800H Owners, I have owned mine for 4 months now and have just performed the expand RX/TX mods and it works very well indeed. PLEASE NOTE: THE J.PEG PICTURES ATTACHED TO THIS FILE SHOW THE AUSTRALIAN MODEL RADIO, there are two diodes less in the AUS MODEL than what is shown in the radio that is already circulating on the Internet. Remove the large single screw that holds the only cover on, be careful when lifting this cover off with a small bladed screwdriver because it is held quite tight with spring loaded contacts down both sides, once this is done turn radio so fan end is facing toward you and locate CPU under tin shield at fan end and link W13 is to the right of CPU. The two J.PEG PICTURES should be easy to follow and you can zoom and print them using PAINTSHOP PRO or COMPUPIC.
My radio will now RX 800 TX 479

118 - 136 is AM RX ONLY

I have not check its RX or POWER SPECS since I performed the mods but from the reports that I have had it would seem that it works very well. Now after the mods are finished you have to reset the CPU in a different way to that described in the instruction manual, with the radio OFF hold down the left and right BOTTOM or fourth menu buttons and turn the radio on, it should now be reset, expanded and ready to be programmed because all memory information will be erased. I take no responsibility for these modifications if you stuff up but if you use a good quality soldering station and are careful it is
not a hard mod to do,..but my next project could be a different story I also own a new IC-Q7E HANDHELD and I am going to have a go at modifying it as well, if that is successful also I will post that on the NET and WW PACKET with pictures.
For those who maybe interested I use a SONY MAVICA FD71 digital camera.This information has been supplied by David Spicer, VK7ZDJ 5a Helen Street, ULVERSTONE, 7315.
Tasmania, Australia. email: vk7zdj@southcom.com.au.MODIFICATION.NET
This modification is read 2191 times.

23-08-1999

(IC-2800) IC-2800/HM98 tx-audio mod
From: PA3HGT@ON6AR.#AN.BEL.EU When you own a ICOM 2800H with the HM98 mike , use this nice trx in the mobile like i do, receive sometimes complains about the hollow modulation and pick up too many backgroundnoise ? Then maybe this is the solution too eliminate this problem. Solder a capacitor between 10 - 47 nf paralell on the mic-element. If you opened the HM98-mike , you can see that the audio cannot applied properly to the mike-element. To change that , you've too drill a small hole of 1mm so that the audio is applied into the center of the mic-element.
This modification is read 2312 times.

31-10-1999

This modification is read 536 times.
(IC-3) Low audio speaker mike on IC2A, 3A, 4A OR 02AT
This modification is read 367 times.
(IC-32) Out of band mod for the IC-32AT
This mod allows the unit to RX-TX outside both ham bands, plus function as a crossband repeater! BE CAREFUL THAT YOU DON'T INADVERTENTLY TRANSMIT! DISASSEMBLY 1. 2. 3. 4. Remove the battery. Loosen but do not remove the two screws holding the PTT switch plate. Remove the 4 screws on the back of the radio. Now remove the front of the HT by carefully lifting the bottom edge and then pulling it down so it clears the top of the HT. Be carefull as there is a ribbon cable attached. 5. Unplug the Speaker/Mic plug from the main chassis to allow the front conver to be fully opened.
MODIFICATION (Refer to figure 1.) 1. 2. 3. 4. Remove D907 Remove D913. Move D912 down to next pad. (D???, bottom location) Add diodes Da and Db (1N914 or Equiv.).
VCO ADJUSTMENT 1. Unplug and remove the PTT/FUNCTION circuit board and lay it aside. 2. Remove the top circuit board by removing the screws located in each corner of the board. These are the ones that are recessed and not the ones on top of the board. 3. Carefully pry up the circuit board until it can be folded out. Plug in the PTT/Function button circuit board cable. 4. Hook up the battery and reset the CPU by holding down the "Function" and "A" buttons and cycling power off and on. 5. On the bottom circuit board are located the two VCO's (refer to figure 2). The left hand VCO is for VHF and the right hand VCO is for UHF. Located just to the left of the UHF VCO is a resistor standing on end. Hook the V. O. M. positive lead to the top of this resistor. The negative lead goes to ground. 6. Under aluminum tape on each VCO is the adjustment point. Normally, the VHF VCO will not require adjustment. The VHF adjustment is L554, the UHF adjustment is C510. Adjust the desired VCO for a +.5vdc reading for the lowest frequency you wish to tune on that band. Don't forget to retape the holes on the VCO's. 7. Disconnect the battery and carefully reassemble the radio. DON'T PINCH ANY WIRES! CROSSBAND REPEATER COMMANDS 1. Enter one VHF and one UHF frequency into each VFO. (Offsets won't work.) 2. To enable crossband repeater, hold down "FUNCTION" buttom and key in, [C] [6] [D]. Then release "FUNCTION" button. 3. To disable crossband repeater, wait until handheld is in receive only and then hold down "FUNCTION" button and key in, [D] [C]. Then release "FUNCTION" button. *** Once handheld retransmits a signal from opposite band you cannot disable crossband function untill squelch closes and handheld quits transmitting! *** Figure 1

This modification is read 542 times.
(IC-475) Prevent a decrease in RF power output in high ambient temperatures
Note: 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. Bulletin #: 24487-001 Procedure Replace R55 on the RFYGR board (currently 22 ohm 1/8 watt) with a 33 ohm 1/8 watt resistor.
This modification is read 517 times.
(IC-475) IC-475 Freq. steps mod
This modification is read 545 times.
(IC-475) Power control modification
replace R87 (470k) with 100k cut "POCO" wire (pin 3, P1/J1, MAIN, orange) at the plug (P1) connect the "POCO" wire to gate 2 of Q13 (e.g. via top of R87)
adjust R250 (SWR protection), R256 (low power level) & R259 (high power level) fully counter-clockwise. (this will give you full SWR protection, but cancels the ALC in normal operation). put the front plate RF PWR in full output position (clockwise) and adjust R82 (Q13 output attenuator) until you have the nominal output power (initially the output power will be higher because you removed the regulation, but the PA will be saturated). the balance between FM, CW & SSB output can be adjusted with R137 (CW carrier level) & R105 (FM carrier level). other interesting adjustments: R135 (mixer balance i.e. SSB carrier suppression), R133 (TX BFO output level).
This modification is read 534 times.
(IC-475) Restoration of pass band tuning
This modification is read 525 times.
(IC-475) Splitting into RX- and TX paths
(IC-475) Modification of cw pass band (BFO)
For readjusting the BFO you need another transceiver (TRX2) with correct tracking. 1. Receive on TRX2 and transmit in CW. Adjust the VFO (with the RIT off !) of TRX2 until you have the desired side tone in CW mode. (e.g. 800 Hz - can be found by beating the tone with the side tone oscillator). 2. Transmit on TRX2 and adjust Ly (CW-R) until you have the desired side tone in CW mode. (you are setting the ~800Hz
difference between CW-R & CW-T). 3. Adjust Lx (CW-T) for preferred USB/CW receive passband. You might have to repeat the tuning once again, as there is some interaction between the adjustments (diode switching for high impedance RF circuits are not perfect !). If you would like to adjust the LSB passband, this should be done by adjusting the capacitor C, before adjusting the coils.

Das spart einen mords Haufen Arbeit, weil man am 475H nur sehr beschwerlich an die Buchse in der Rckwand hinkommt. Um diese Leitung umzumnzen mu man am Connector J13 den Pin 4 abklemmen, das ist eben diese Leitung zu Pin5 der Erweiterugsbuchse, und sie an PIN9/IC 6 anlten. FERTIG. Dazu braucht man nur den unteren Deckel des Gertes zu ffnen. J13 sitzt nur ca. 3 cm vom IC6 entfernt, und wenn man die Leitung an PIN 4 (schwarz isoliert) knapp am Stecker abzwickt oder aus dem Stecker herausbastelt reicht es problemlos bis zum IC hinber. Die dazugehrige Abschirmung auf Pin5 / J13 lt man natrlich dran. Das RX-Signal liegt jetzt logischerweise an PIN 5 der AQSBuchse am Gert, nicht an PIN 11, wie von DG5EM ursprnglich beschrieben. Fragen bitte an DH1SAJ @ DB0RBS, MYBBS DB0SAO ist z.Zt. ohne LINK 73 de Jochen, DH1SAJ @ DB0RBS
This modification is read 507 times.
(IC-490) Modifikation af IC-490 for 9K6
1. The back section is fixed by four screws through the side plates. Remove those screws and bend the back section as far as the wiring allows. You will see the screw heads when the top and bottom cover of IC490 have been removed. 2. 470 nF = 0.47 F The capacitance could be higher, but there are space limitations inside the rig underneath the IC490 Main Unit print. For the time being you will not need the connection with varactor D3 for any satellite, but you may need it for a 9600 baud terrestrial net. It will, however, be feasible to prepare that connection as well when the AF/FM and AF/SSB connections are being built. 3.
+12V -------+ 4.7 k X 850 k X 0.47 F +----> SSB out to 9-pin connector #3/IC3 / SSB in ->-------*cable-----+-- BC337 or similar NPN transistor 0.47 F 150 k X -
*cable from 0.47 F condenser on the Main Unit to the amplifier located at an empty spot within the rig You will need the above amplifier only when SSB signal level at #3/IC3 will not be sufficient for your TNC. I am not familar with TAPR 1200 baud psk modem. 4. As you know doppler shifts UO-14 frequency downwards only from rise to set. Often 435.077 ---> 435.058 MHz. Consequently IC490 needs down commands only. It will get such a command each time the calculated frequency drops by 1 kHz. My program calculates the current frequency, not doppler shift only. I initally tune my Rx to the frequency I know UO-14 has, when rising above horizon. I dont need to hear UO-14 at that moment. In fact I know UO-14 frequency any time without listening, just by looking at the monitor. When I tune my Rx at that frequency I know that UO-14 is there. The control system then steps the frequency down as frequency calculation tells it to do. I think you will not need the diagram for the circuitry since your tracking program apparently does not tell the above things. You would find Finnish speaking fellows at the subsidiaries of Finnish companies, like EPL-Kone Pty, in your country. That would unfortunately not solve the program problem. Pate OH2SN @ OH2RBI

DRAWBACKS/FLAWS Extended VHF receive requires modification (see below). Poor sensitivity above 162 MHz. Noise blanker does not work on AM. Very irritating pulse noise on AM while the car's engine is on. The blanker works well on other modes (except FM, where it is not needed). Not good for listening to AM while driving. A rather serious flaw in my opinion, since my $40 CB has a noise blanker that works well. Poor QSK (full break-in) capability. Not recommended for high-speed CW operators who want QSK. Use semi-break-in instead. No CW narrow filter. You can install one as an extra-cost option or use an external CW filter or DSP unit. The built-in speaker provides surprisingly good audio for its size, but you will probably want to use an external speaker. The speaker can be connected to the face plate or to the rig itself. Automatic repeater offset is not programmed into the rig. You need to program -600 or +600 yourself through the menu system. This is not a problem if you store your favorite repeaters into one of the 100 memories. The S-meter is inaccurate below S9. Above S9, it is quite accurate. High prices for accessories (typical of just about all other vendors)
The AH-3 antenna tuner is shipped with an unshielded cable, which picks up a lot of auto engine noise. You need to make your own shielded 4-wire cable. The AH-3 also blocks signals above 54 MHz. It also only works for HF, not for 6m or 2m. Expect performance and receiver sensitivity similar to other rigs in this price range. This is a low-end rig in terms of price. For price vs. performance, this is probably the best amateur radio of all time. However, it will not outperform your $4000 rig. You probably won't win contests with it. You will have a lot of fun and own a nearly ideal rig for mobile work.
HINTS AND TIPS 1. Take time to read the manual. The menu system will be bewildering unless you read the manual. One you get used to it, you will find the rig to be amazingly easy and fun to use. 2. You need to set the mode to wide FM to receive FM or TV broadcasts. Tune to the station, press the MODE key until the front display shows FM, then press and hold the MODE key for 2 seconds. WFM will appear in the display, and you will hear the station with nice audio. 3. Don't use the noise blanker on AM. It will not be effective and may distort your audio. 4. Don't use the QSK feature. 5. The rig gets very hot while transmitting. Keep the top of the radio clear to allow air circulation.
This modification is read 3247 times.
(IC-706) Enables out-of-band transmit for 1.6 MHz to 54 MHz
Enables out-of-band transmit for 1.6 MHz to 54 MHz. This does not enable extended VHF transmit This does not enable AM or FM broadcast band transmit. Your memories will be cleared after this modification, since you need to reset the CPU. 1. Open the top of the radio by removing the 3 top screws and 2 side screws. Look at the radio with the front panel facing you. 2. Gently pull up the speaker and set is aside without damaging the speaker or the wires that attach it to the rig. 3. Note the silver rectangular box near the middle of the PCB marked something like "9 MHz SSB Filter". 4. Move your eyes up from this filter toward the back of the radio. Just before you get to the "D 108" marking, you will see two tiny diodes, two blank spaces, and one additional diode. They look something like this:

Attenuator protecs strong signals from distorting (20 dB); FUNC + 0 BOOT: Partial: MODE + POWER --> DIAL --> ENT (no changes in memory) All: CLR + POWER --> DIAL --> ENT 73s de Milton Teuner - PY3PSI SWL: ZZ3-0149 py3psi@gw.ab6qv.ampr.org.MODIFICATION.NET
This modification is read 1916 times.

27-11-2001

(IC-R10) ICOM R10 Receiver Modification to Provide S-Meter Output
Author: Doppler Systems Inc.
April 21, 2001 A Technical Application Note from Doppler Systems Inc. Acknowledgements This application note was submitted by Lt. J.G. Peter Arts from USCG Boston and was based on instructions originally received from Phil Godbold of Adur Communications in England. Introduction The purpose of this application note is to describe the modification of an ICOM IC-R10 receiver to provide received signal strength indication (RSSI) through the ring terminal of the external speaker jack for use with various Doppler radio direction finders. The modification consists of soldering a resistor between two internal contacts on the radio IC board. Items Required
ICOM IC-R10 Communications Receiver Radio Shack 2711321 1Kohm ( watt) Resistor Radio Shack 274375B Stereo Signal Splitter Y Adapter Plug Insulation Spray or Small Heat Shrink Small Philips Screwdriver Soldering Iron with Fine Nib Heat Sink Clamp
Case Disassembly Instructions Note - There are three different size screws used to connect the R10 Receiver. When removing screws, keep the one short, one medium, and five long screws separate. 1. Manually remove battery cover.
2. Using small screwdriver, remove 7 mounting screws (locations shown in below diagram). 3. Carefully open receiver case to expose electronic circuitry (see photograph at end of instructions). 1Kohm Resistor Jumper Preparation
1. Form resistor leads to fit the intended application as shown in the following figure, i.e. a jumper between the Signal Meter output terminal "SM" and the speaker output terminal "QS." 2. After forming the resistor leads, cover the leads with insulated sleeving or insulation spray. 3. Using soldering tools, "tin" each lead end. Resistor Installation 1. Using soldering tools, apply a small amount of solder (tin) both the "SM" and "QS" copper pads which are located on the circuitry behind the battery compartment. Refer to the below figure. 2. Using soldering tools, carefully mount each 1Kohm resistor leads (one to the "SM" terminal, the other to the "QS" terminal). Also see photograph at end of instructions. Avoid excessive or prolonged heating. Case Reassembly; 1. Carefully mate the R10 receiver case together, taking care not to jam any rubber plugs or the flex circuit. 2. Re-install the seven (7) screws in the same locations which they were removed from, i.e. 1 short, 1 medium, and 5 long screws (see figure). Do not over-tighten these screws. 3. Manually install battery cover to the receiver. Installation of Y Adapter Plug

+ 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9
+ SCAN Priority Scan/Ch Scan + S.CH Channel Masking + CLEAR End progamming mode
--------------------------------------------------------------------------Channel select: Standard method (up/down Frequency: Hold [FUNC], Press [5], enter [FUNC] Rx CTCSS: Hold [FUNC], Press [2], enter [FUNC] Tx CTCSS: Hold [FUNC], Press [1], enter [FUNC] arrows or CH# + [ENTER]) 6 dig freq, [ENTER], release 2 dig code, [ENTER], release 2 dig code, [ENTER], release

Offset Freq:

Hold [FUNC], Press [4], use [#] for up offset, [*] for down offset, then enter freq to offset by (ie: [#] [0] [0] [0] [0] [0] for no offset, [#] [0] [5] [0] [0] [0] for the standard +5MHz UHF offset), [ENTER] Timeout Timer: Hold [FUNC], [8], Release [FUNC] Tx Inhibit: Hold [FUNC], [9], Release [FUNC] Special Channel Number: Hold [FUNC], Press [7], enter the special channel number (17-99), [ENTER], Release [FUNC]l Data Transfer MASTER: Hold [FUNC], [BEEP], Release [FUNC] Data Transfer SLAVE: Hold [FUNC] with power off, turn on, release [FUNC]
Helt to fint the U16 jumper >Questions: > >The file implies that the U16 must have a jumper in a certain spot, in >order for it to be user-programmable. Where should this jumper be? 3/4 way down the left side of the logic board which is inside the front cover. >The file contradicts itself: when a new frequency is being inserted, >should it be entered as five or six digits? The frequency must be inserted in six digits. The decimal point must return to be a valid frequency entry. Also you must hold the function button while entering the frequency and then press enter before releasing the function buttion. Date: 07-01-2001 Subject: Extra info The mods for the Midland series 70-254A/B/C and -154 radios are the same as for the Icom IC-U16 series! Make sure the jumper on the BOTTOM of the logic board is removed before trying programming the unit. Drew Date: 21-07-2001 Subject: More info Just a short note to let you know that THE ICOM IC-h16 is the VHF equivalent of the IC-U16 and programs the same way. The Midland 70-154 is also the same as the IC-H16. Also, the Midland units call the FUNC button SHIFT. In either case it is the button closest to the top of the radio above the PTT. Date: 28-12-2001 Subject: ICU-16 Battery Would like to know where can i find a cheap place in California to buy a Battery for the ICU-16 radio mine isnt working at all

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
_____________________________________________________ -------| | | CPU-1 | | | ---------------------.<: <-D1. D2-> V D3->. V. V <-D? ---------| |fuse | | ----------------| | | CPU-2 | | | -------| | |--| | | P | | T | | T | | | |--| | | | | | | |