Icom IC-746 Installation guide

IC-746 FAQ
Icom IC-746 FAQ
Frequently Asked Questions
About the
Icom IC-746 HF/VHF Transceiver
Coordinator
Dana Hoggatt
KB9SSS
[email protected]
Copyright (c) 2001,2002,2003 by Dana Hoggatt, all rights reserved.
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Recent Changes
2003.02.06 Added another QST article to the article list
2003.02.06 Added current vs voltage chart to power supply section.
2003.02.06 Added Q/A on zero-beating CW signals
2003.02.05 Added info on annotated copy of IC-746 Instruction Manual
2003.02.05 Added info on an Italian copy of the IC-746 Instruction Manual
2003.02.04 Added another SEND amp interface
2003.02.04 Added another microphone pre-amp circuit
2003.02.04 Added a Q/A about circuit schematics
2003.02.03 Added a Canadian repair center
2003.02.03 More info on LCD scratch removal
2003.02.02 Added ACC-2 pin-out diagram
2003.02.02 Added ACC-1 pin-out diagram
2003.02.02 Added MIC pin-out diagram
2003.02.01 Added errata about receiver selectivity
2003.02.01 Added extensive info on low RF output power
2003.02.01 More non-746 information links
2003.02.01 Add Q/A on intermittent audio
2002.12.04 Minor/trivial corrections/additions, too numerous/small to list separately
2002.12.03 Added another article
2002.12.03 First rough draft in document format
2002.11.29 Started converting ASCII format to document format
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Table of Contents
ICOM IC-746 FAQ........................................................................................................... 1
RECENT CHANGES....................................................................................................... 2
TABLE OF CONTENTS.................................................................................................. 3
1 ADMINISTRIVIA........................................................................................ 9
1.1 What is an FAQ?................................................................................................... 9
1.2 Where can I get a copy? ....................................................................................... 9
1.3 Where do I send feedback? .................................................................................. 9
1.4 What are the future plans for the FAQ? .......................................................... 10
1.5 What questions still need to be answered? ....................................................... 11
1.6 What does this abbreviation or TLA mean? .................................................... 11
2 GENERAL INFO...................................................................................... 12
2.1 Should I buy an IC-746? .................................................................................... 12
2.2 What are the IC-746's features?........................................................................ 12
2.3 How does the IC-746 stand up to the ______ ? ................................................ 12
2.4 Where can I buy/sell a used IC-746?................................................................. 13
2.5 How much is a used IC-746 worth? .................................................................. 13
2.6 Is there a dedicated HF net for the IC-746?..................................................... 14
2.7 Are there electronic copies of 746 instruction manuals?................................. 15
2.8 Are there electronic copies of the circuit schematics?..................................... 15
2.9 Are there electronic copies of 746 service manuals?........................................ 16
2.10 How do I fix the font substitution error in the PDF manual? ........................ 16
2.11 How does an IC-746s differ from an IC-746? .................................................. 16
2.12 What is the IC-7400? .......................................................................................... 17
2.13 What is the IC-746-PRO? .................................................................................. 17
2.14 Where can I find info on other Icom rigs? ....................................................... 18
2.15 Where is info on the 706, 718, 756, 765, 735, ... ................................................ 18
2.16 What articles have been written about the IC-746? ........................................ 19
2.17 Can I transmit 100w at 100% duty cycle on CW, SSB, RTTY, PSK, etc…? 21
2.18 I thought the LCD was blue, but photos show it as green?............................. 22
2.19 Can the IC-746 work on the 60m band?........................................................... 22
2.20 Can the IC-746 work on the Alaska Emergency Frequency?......................... 22
3 ACCESSORIES....................................................................................... 23
3.1 POWER SUPPLIES................................................................................. 23
3.1.1 What power supply should I use with the IC-746?.......................................... 23
Continuous vs. Intermittent Load ......................................................................... 25
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3.2 ANTENNAS............................................................................................. 28
3.2.1 What antenna should I use with the IC-746? ................................................... 28
3.2.2 What range can the automatic antenna tuning unit (ATU) handle? ............. 29
3.2.3 Will the internal ATU handle "random" wire antennas? .............................. 29
3.2.4 Will the internal ATU handle "long wire" antennas?..................................... 29
3.2.5 Are there any "tips" to using the ATU? ........................................................... 29
3.2.6 Can I use the internal ATU along with an external ATU? ............................. 29
3.2.7 Does the internal ATU work on receive?.......................................................... 30
3.2.8 Any other "gotchas" with the internal ATU? .................................................. 30
3.2.9 How do I use a "beverage" antenna?................................................................ 31
3.2.10 How do I use different antennas for receive vs. transmit?.............................. 31
Split VFO Method................................................................................................. 31
External Antenna Switcher Method...................................................................... 31
External RF Sense Antenna Preamp Method........................................................ 31
3.2.11 How do I measure SWR while in SSB?............................................................. 31
3.2.12 How do I tune up in CW without a key? .......................................................... 32
3.2.13 What about using an external, automatic, ATU? ............................................ 32
3.2.14 Can the TUNER button activate an external automatic ATU?...................... 33
3.2.15 Why doesn't the rig SWR meter match my external SWR meter?................ 34
3.2.16 Which SWR meter should I trust: internal or external? ................................ 34
3.2.17 How do I repair the detector diodes in the internal ATU? ............................. 35
3.2.18 How do I switch between more than two antenna ports? ............................... 35
3.3 MICROPHONES...................................................................................... 37
3.3.1 What is the best microphone to use with the IC-746? ..................................... 37
3.3.2 Can I hook up a different microphone directly to the IC-746? ...................... 37
3.3.3 Can I use a Heil microphone with the IC-746? ................................................ 38
3.3.4 How do I adjust the IC-746 for a Heil headset?............................................... 38
3.3.5 Do I need a pre-amp to use a Heil microphone? .............................................. 38
3.3.6 What are the pin-outs on the microphone connector? .................................... 39
3.4 KEYERS .................................................................................................. 40
3.4.1 Can I hook my straight key to the front "Elec Key" Jack?............................ 40
3.4.2 Can I connect my own Electronic Keyer to the IC-746?................................. 40
3.4.3 How do I wire up my paddles for use with the internal keyer?...................... 40
FOR A STRAIGHT KEY OR EXTERNAL KEYER:......................................... 40
TO USE THE BUILT IN ELECTRONIC KEYER WITH PADDLES: .............. 40
3.4.4 Can I use the internal and external keyers at the same time? ........................ 41
3.5 AMPLIFIERS ........................................................................................... 42
3.5.1 How do I hook up an Icom IC-PW1 RF power amplifier?............................. 42
3.5.2 What if I hook up more than just an IC-PW1?................................................ 42
3.5.3 How do I hook up a non-Icom RF power amplifier?....................................... 43
3.5.4 Do I really need an external amplifier switching relay? ................................. 43
3.5.5 Why do I need an external amplifier switching relay?.................................... 43
3.5.6 My SEND relay seems to be stuck, what do I do? ........................................... 47
3.5.7 Where can I get an external switching relay? .................................................. 47
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3.5.8 Can't I just use the ACC port to key my amp?................................................ 48
3.5.9 How do I build my own SEND relay isolation circuit/relay?.......................... 48
3.5.10 Why do I get IC-746 birdies when I turn on my IC-2KL?.............................. 49
3.5.11 How do I hook up a Yaesu Quadra (VL-1000) amp to an IC-746?................ 49
3.6 TNC ......................................................................................................... 50
3.6.1 How do I hook up a TNC to the IC-746?.......................................................... 50
4 IF FILTERS.............................................................................................. 51
4.1 How many optional IF filters can I install into the IC-746? ........................... 51
4.2 What optional IF filters are available for the IC-746?.................................... 51
4.3 Which optional IF filters should I buy?............................................................ 52
4.4 What is an IF filter's "bandwidth"? ................................................................. 52
4.5 What is an IF filter's "shape factor"?............................................................... 52
4.6 Why do filter "bandwidth" or "shape factor" matter?.................................. 53
4.7 What is considered to be a narrow filter? ........................................................ 53
4.8 What are narrow IF filters used for?................................................................ 53
4.9 Can an IF filter be too narrow?......................................................................... 54
4.10 What's the difference between IF filters from Inrad vs. Icom? ..................... 54
4.11 Which IF should I put an optional filter into? ................................................. 55
4.12 What's different between IF filters for 9Mhz vs. 455Khz?............................. 55
4.13 What are the 9Mhz IF filters best for? ............................................................. 55
4.14 What are the 455Khz IF filters best for?.......................................................... 55
4.15 How do I get the best results from TPBT? ....................................................... 55
4.16 How do I configure the IC-746 to use an optional filter?................................ 56
4.17 How do I configure the IC-746 to use a non-Icom filter?................................ 56
4.18 How do I use a CW filter in SSB mode to receive PSK31?............................. 56
4.19 Why is there only one optional 455Khz IF filter slot?..................................... 57
4.20 Any tips on installing 9Mhz Inrad filters?........................................................ 57
4.21 Where do I install a 2nd Inrad 9Mhz IF filter? ............................................... 57
4.22 Where can I find more information on filter characteristics?........................ 57
4.23 What are some popular filter combinations?................................................... 58
5 COMPUTER CONTROL.......................................................................... 59
5.1 How do I wire the IC-746 up for computer control?....................................... 59
5.2 What cables do I need?....................................................................................... 59
5.3 What are CT-17, OPC-478, OPC-662 all about?............................................. 59
5.4 Do I need a special cable to connect a CT-17 to an IC-746? ........................... 61
5.5 What is the control protocol for the IC-746? ................................................... 61
5.6 What is CI-V?...................................................................................................... 61
5.7 What is the CI-V address of the IC-746?.......................................................... 62
5.8 What computer software is available?.............................................................. 62
5.9 Where can I get computer software and upgrades?........................................ 62
5.10 Why doesn't computer software update freq when tuning the 746?.............. 65
5.11 How do I wire up the IC-746 for use with PSK31?.......................................... 65
5.12 Why isn't my computer control working?........................................................ 65
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6 PROBLEMS AND CLARIFICATIONS..................................................... 66
6.1 What's that funny rattling noise I hear when I first power on?..................... 66
6.2 What's that "click" I hear as I tune across certain frequencies?................... 66
6.3 Why doesn't the ALC meter work while adjusting the "mic gain"?............. 66
6.4 Why can't I set numbers into memory names, CW keyer, etc...? .................. 66
6.5 Why isn't my output power up at 100 watts?................................................... 67
Low DC supply voltage. ....................................................................................... 67
You have an IC-746s instead of an IC-746........................................................... 67
Blown Internal Fuse.............................................................................................. 67
The RF driver transistors may have failed............................................................ 68
The RF power amplifier transistors may have failed............................................ 68
Blown Output Detector Diodes............................................................................. 68
Your ALC circuit may have failed........................................................................ 68
SWR Foldback...................................................................................................... 68
Confused Meter Readings..................................................................................... 68
CW Break-In Turned off....................................................................................... 69
Internal adjustments set a little low ...................................................................... 69
6.6 How low can the IC-746 supply voltage be?..................................................... 69
6.7 The backlight in my LCD has stopped working. What's wrong? ................. 70
6.8 Is there some way to get the Icom-746 to generate DTMF tones?.................. 73
6.9 Why don't my "band edge beeps" match the US amateur bands?................ 74
6.10 Can I transmit all the way out to the "band edge beeps"? ............................. 74
6.11 Can I reprogram the "band edge beeps"? ....................................................... 74
6.12 Do we know anything about the "band edge beeps"?..................................... 74
6.13 How I reset back to factory default settings? ................................................... 75
6.14 What "birdies" does the IC-746 have? ............................................................. 75
6.15 How do I adjust the LCD display? .................................................................... 76
6.16 The Noise Blanker doesn't seem to do any good. What's wrong?................. 76
6.17 How do I get rid of ignition noise? .................................................................... 77
6.18 How do I adjust or make the NB work better?................................................ 77
6.19 How do I fix a loose rubber grip from the tuning knob? ................................ 78
6.20 Where should I go for repairs?.......................................................................... 78
6.21 How do I fix scratches on the LCD?.................................................................. 80
6.22 What can I do about sticky switches? ............................................................... 80
6.23 Why does the S-meter seem low on 2m FM?.................................................... 81
6.24 Why is my tuning shaft/knob loose and sloppy?.............................................. 81
6.25 Why is my audio cutting in and out? ................................................................ 81
7 MODIFICATIONS .................................................................................... 82
7.1 What TX/RX "mods" are there for the IC-746? ............................................. 82
7.2 What other "mods" are there for the IC-746?................................................. 82
6Khz wide IF filters .............................................................................................. 82
Safe 2m TX/RX Sequencing................................................................................. 83
Simple CAT interface ........................................................................................... 83
Separate 2m TX/RX Antenna Lines ..................................................................... 83
Increased MONITOR Volume.............................................................................. 84
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LCD Driver Transistor Replacement.................................................................... 84
Poor Man's TCXO ................................................................................................ 85
Upgrading Stock Ceramic IF Filter to a Crystal Filter ......................................... 85
7.3 Can I increase my RF power output beyond 100w?........................................ 85
7.4 I'm brave; what untested "mods" are there?................................................... 86
Replacing PIN Diodes in the Demodulator .......................................................... 86
Removing the BCB Attenuator............................................................................. 87
7.5 What "external" mods are there for the IC-746?............................................ 87
Remote, Direct Frequency Entry Keypad............................................................. 87
Cordless Headset Microphone .............................................................................. 87
Automatic Antenna/Amplifier Selection by Band................................................ 87
2m TX/RX Sequencer........................................................................................... 88
External Tuner Pulser ........................................................................................... 88
Unmuffling Icom Hand Mics................................................................................ 89
8 MISC........................................................................................................ 90
8.1 Are there different versions of the IC-746?...................................................... 90
8.2 Can I operate 2m on reduced power?............................................................... 90
8.3 Where can I find plugs for the ACC connectors?............................................ 90
8.4 What are the pin-outs on the ACC-1 connector?............................................. 91
8.5 What are the pin-outs on the ACC-2 connector?............................................. 92
8.6 Does audio to pin 4 of ACC-1 trigger the VOX?.............................................. 92
8.7 Where can I get replacement power connectors? ............................................ 92
8.8 Where can I get replacement microphone connectors? .................................. 93
8.9 What is "Lo-Fi" SSB operation?....................................................................... 93
8.10 What is "Hi-Fi" SSB operation? ....................................................................... 93
8.11 How does one improve the fidelity of a received signal?................................. 94
8.12 How does one improve transmission fidelity?.................................................. 95
8.13 Can the IC-746 transmit at less than 5 watts? ................................................. 95
8.14 How do I turn on both HF pre-amps at the same time?.................................. 95
8.15 How do I adjust the 746 for best AM performance? ....................................... 96
8.16 Is the IC-746 suitable for CAP and MARS operation? ................................... 96
8.17 How do I adjust the Noise Reduction (NR)? .................................................... 96
8.18 How do I program a non-standard repeater offset?........................................ 97
8.19 How do I turn on repeater (PL) tones?............................................................. 97
8.20 How do “zero-beat” a CW signal? .................................................................... 98
INSTRUCTION MANUAL ERRATA ............................................................................. 99
Page:2 Incorrect Page References.................................................................................. 99
Page:6 External speaker and remote interface jacks are swapped. ........................... 99
Page:9 Incorrect page references................................................................................... 99
Page:15 BAND EDGE BEEPS simply do not work as expected................................... 99
Page:19 SSB TX Tone affects more than SSB ................................................................ 99
Page:22 TRANSMIT button does not transmit on CW................................................. 99
Page:27 Only one bar for CW sidetone level, not two.................................................. 100
Page:32 No ALC adjustment for FM............................................................................. 100
Page:33 Incorrect filter diagram.................................................................................... 100
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Page:42 Incorrect Page Reference ................................................................................. 100
Page:46 No ALC adjustment for either AM or FM ..................................................... 100
Page:46 Speech compressor............................................................................................ 100
Page:53 Enter numbers via keypad, not tuning dial.................................................... 101
Page:56 Incorrect Page References................................................................................ 101
Page:68 Unclear Voltage Specification.......................................................................... 101
Page:70 Overoptimistic SWR Specification.................................................................. 101
Page:77 Unclear UT-102 Installation Instructions....................................................... 101
Page:79 Incorrect SEND Relay Specifications.............................................................. 101
Page:84 Incorrect Bandwidth listing ............................................................................. 101
SERVICE MANUAL DISCREPANCIES...................................................................... 102
Identity of Q302 102
Identity of R1271 102
GLOSSARY ................................................................................................................ 103
CONTRIBUTORS + ACKNOWLEDGEMENTS .......................................................... 105
DISCLAIMER & COPYRIGHT .................................................................................... 108
REVISION HISTORY .................................................................................................. 109
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1 ADMINISTRIVIA
1.1 What is an FAQ?
1.2 Where can I get a copy?
1.3 Where do I send feedback?
Welcome to the IC-746 FAQ.
Short Answer
FAQ stands for "Frequently Asked Questions". It tries to cover common questions,
problems, and issues associated with Icom's IC-746 HF/VHF amateur radio transceiver.
The master copy is kept at:
http://groups.yahoo.com/group/IC746/files/IC746-faq.pdf
Mirrored copies (after a short delay) appear at:
http://www.qsl.net/kb9sss/IC-746/IC746-faq.pdf
http://www.skysdaughter.com/icom746-faq.pdf
You do not need a Yahoo email account to access the master copy, however, you will need a
logon account. Yes, that is a subtle but hopefully minor distinction. Not everyone is willing
to have a login account at Yahoo (even if it is free), which is one of several reasons for
maintaining the mirror sites.
Also, we post the FAQ monthly to:
news:rec.radio.amateur.equipment
usually sometime between the 1st and the 10th.
You can post questions/comments about the FAQ to the above newsgroup.
Long Answer
The format of this FAQ should become apparent right from the start. Questions are grouped
into related sections and subsections, roughly in the form of an outline.
When possible/practical, there will be both a short and long answer. The short answers will
try to be brief and to the point, typically about one paragraph. While correct, quick, and
immediate, it will often gloss over subtleties and details. The long answers will cover theory,
alternatives, dissenting opinions, and other supplemental material. We try not to
unnecessarily duplicate information between the answers (this one is an example of that).
Long answers may go on for several pages.
The questions that are addressed here (as well as the answers) come from several sources.
This FAQ was originally created and hosted by folks on a Yahoo e-mail discussion group at:
http://groups.yahoo.com/group/IC746/
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They have extensive information on the IC-746, including bookmarks and a file download
area.
http://www.qth.net/ hosts a more generalized Icom e-mail list that covers all models, not just
the IC-746. You can lookup more information or subscribe to that list at:
http://mailman.qth.net/mailman/listinfo/icom/
There's a search engine for the above list, but it's accessed from a Hallicrafters site at:
http://www.w9wze.org/
Some of the info here originally appeared upon a bbs style on-line discussion group that used
to be at:
http://vartel.com/icom746/icom746index.html
(The site not been responding since Jan-2002)
There are also the following newsgroups:
news:rec.radio.amateur.equipment
news:rec.radio.swap
Specific comments or clarifications can be sent directly to the FAQ coordinator. "Content
submissions" would be greatly appreciated. However, general discussion/debate over the
answers is best done in a more public forum, like one of those mentioned above.
1.4 What are the future plans for the FAQ?
Starting in February, 2003, this FAQ went from a text ASCII format to Adobe Acrobat
(PDF) format. This is facilitating the inclusion of charts and diagrams, along with
bookmarks and hyperlinks. That process will continue. To view or print the document, you
will need a copy of the Acrobat Reader, available for free from:
http://www.adobe.com/products/acrobat/readstep2.html
Most of the power supply information should be separated out into a separate FAQ that is
applicable to all rigs. This fits in better with the new ICOM Resource pages at:
http://www.qsl.net/icom/
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1.5 What questions still need to be answered?
There are plenty of topics that still need or deserve to be covered. Here are some topics and
details we'd like information on (in no particular order):
• Levels and impedances of all audio connections (mic, phones, acc, etc...)
• We still do not have enough reliable reports to confirm which "birdies" (if any) actually
exist.
• How does one go about hooking the 746 up for PSK, TNC, and CI-V operations at the
same time?
• CW Zero-Beat confusion (as well as BFO and "reverse" operation)
• More information is needed on the front panel power switch and its interaction with the
extra pins on the T-connector in the back.
• More service and repair information
• Better explanation of band stacking registers
• Operating tips
• Instructions on how to use internal ATU
• Better explanation of COMP (gain, FM, etc...)
• Compare/contrast the 746 vs 746PRO
• Does the 746 exhibit a full power spike at beginning of TX?
We welcome and encourage submissions.
1.6 What does this abbreviation or TLA mean?
Hams use a lot of abbreviations and TLAs (Three Letter Acronyms), Toward the end of this
document, is a small glossary to some of the abbreviations we use in the FAQ.
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2 GENERAL INFO
2.1 Should I buy an IC-746?
Yes. Try it, you'll like it.
This FAQ is maintained by happy, loyal, and devoted IC-746 owners. What do you really
think we're going to say?
One thing nearly everyone (both loyalists and detractors) agrees upon is that you should
make every effort to try out a rig before purchasing it.
2.2 What are the IC-746's features?
For features, check out the IC-746 specifications from brochures available at your local
amateur radio equipment store, on-line documents at various vendor sites, or directly from
Icom's WWW site at:
http://www.icomamerica.com/
On-line copies of the IC-746 sales brochure are available at:
http://www.qsl.net/kb9sss/IC-746/IC-746-Brochure.pdf
http://groups.yahoo.com/group/IC746/files/IC-746-Brochure.pdf
Of particular interest might be the on-line copy of the instruction manual.
Most of the 746's problems or faults show up either in this FAQ (eventually) or in one of the
archives at:
http://groups.yahoo.com/group/IC746/files/IC-746-Brochure.pdf
http://mailman.qth.net/mailman/listinfo/icom/
2.3 How does the IC-746 stand up to the ______ ?
Probably the most objective, quantitative comparisons you will find are the QST product
reviews (freely available to ARRL members):
http://www.arrl.org/members-only/prodrev/
An Excel spreadsheet that allows side by side comparison of the technical specifications for
many HF transceivers can be found at:
http://groups.yahoo.com/group/IC746/files/HF-RIGS.xls
Simpler, more limited, comparison charts are available on the Amateur Electronic Supply
WWW site at:
http://www.aesham.com/compare/comp_hf.html
User written reviews can be both more personal and more detailed. They can also be more
biased. You can find plenty of them at:
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http://www.eham.net/reviews
This topic has come up several times on Yahoo's IC746 discussion group. One of the more
interesting threads along these lines starts with message 1012 and ends with message 1028.
I'm told that message 1023 is particularly good. Another good thread starts with 1049 and
ends with 1077.
http://groups.yahoo.com/group/IC746/message/1012
http://groups.yahoo.com/group/IC746/message/1023
2.4 Where can I buy/sell a used IC-746?
Usually when someone asks this on the internet, they are looking for an on-line swap page.
There are, of course, plenty of other options. Most dealers have used/demo equipment.
Hamfests are a traditional favorite, as are "swap nets" on HF.
That said; the two largest forums on the internet for amateur radio gear are the USENET
newsgroup
news:rec.radio.swap
and the infamous eBay auction site.
http://www.ebay.com/
"Amateur Radio Trader" is both a magazine and a WWW site devoted to amateur radio
classifieds:
http://www.amradiotrader.com/
(site not responding Jan-2002)
Yahoo has a small auction site as well:
http://list.auctions.shopping.yahoo.com/23761-category.html?alocale=0us
After those, you have your choice of dozens of dedicated swap sites on the net. A few of
them are:
http://www.arrl.org/RadiosOnline/
http://www.qrz.com/forum/
http://www.eham.net/classifieds/
http://www.k1dwu.net/hamtrader/
AC6V maintains an entire list of swap pages as part of his excellent ham links/resource site.
http://www.ac6v.com/swap.htm
2.5 How much is a used IC-746 worth?
Unlike used cars, there is no official "blue book" for ham equipment. Only YOU can decide
this.
Your best bet is to peruse the archives for
news:rec.radio.swap
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over the past 6 months or so.
You might also check out one of the following sites
Electronic Boneyard Prices:
http://www.geocities.com/CapeCanaveral/Hall/8701/ham/boneyard.htm
E-Bay prices:
http://aade.com/hampedia/prices.htm
Virtual Hamfest - Recent Prices:
http://www.vhamfest.com/prices.html
(site not responding Jan-2002)
Ham Shopper:
http://www.hamshopper.com/
Good luck.
2.6 Is there a dedicated HF net for the IC-746?
Yes, one was started in October 2001.
It convenes 20M SSB near 14.2525 Mhz +/- QRM, on Sunday evenings at 9:00pm Eastern
time (6:00pm Pacific).
The folks that run the net shift it along with Daylight Savings Time in the U.S.A. Therefore,
during "standard" time (last Sunday in October to the first Sunday in April) the net starts at
0200 UTC Monday. During "savings" time (first Sunday of April through last Sunday of
October) the net starts at 0100 UTC Monday.
For the curious, not all of the U.S.A. participates in "daylight savings time". Likewise,
portions of Europe participate, but on a different timetable. A wealth of information on DST
can be found via Yahoo at:
http://dir.yahoo.com/Science/Measurements_and_Units/Time/Daylight_Saving_Time
or within the AC6V link indices at:
http://www.ac6v.com/opaids.htm - CLOCKTIME
or directly from NIST (the National Institute of Standards and Technology) at:
http://www.time.gov/
The folks in the Yahoo IC746 e-mail group try to maintain a net calendar at:
http://groups.yahoo.com/group/IC746/calendar
Yes, you have to be a member of the e-mail group to access their pages, but as a fringe
benefit, you'll even get an automatic e-mail reminder on the day of the event.
Doug, N7BNT, located in Vancouver, WA is usually Net Control, and "K.C." KG9JP in
Phoenix, AZ is usually helping out and hosting the chat room.
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There is usually a IC746 chat room set up on Yahoo Internet Messenger. Click on the "Chat"
button, go to "Hobbies and Crafts", click on the "User Rooms" tab and join in! If you need a
relay to check-in to the net, this is the place to go... The chat room should be up about 10
minutes before net.
We've heard of a few other HF nets devoted to Icom equipment in general. They meet at:
Sunday, 1700 UTC, 14.315 Mhz ssb
Sunday, 2100 UTC, 14.317 Mhz ssb
2.7 Are there electronic copies of 746 instruction manuals?
YES! A PDF (Adobe Acrobat format) version of the IC-746 Instruction Manual is available
on the IC746 Yahoo Group WWW site at:
http://groups.yahoo.com/group/IC746/files/IC-746-Instruction-Manual-Extra.pdf
This version of the manual has a full set of TOC bookmarks, hyperlinks for all intra-
document page references, and comment bubbles for all known errata.
During the first week of November, 2001, Icom made an electronic copy of the original IC-
746 Instruction Manual (along with many others) available on their WWW site at:
http://icomamerica.com/support/documents/index.html
A backup copy of the above manual is available from several locations:
http://groups.yahoo.com/group/IC746/files/IC-746-Instruction-Manual.pdf
http://www.qsl.net/kb9sss/IC-746/IC-746-Instruction-Manual.pdf
Additionally, the FCC posted the IC-746pro instruction manual (and various other
documents) at:
http://gullfoss2.fcc.gov/cgi-
bin/ws.exe/prod/oet/forms/reports/Search_Form.hts?mode=Edit&form=Exhibits&application
_id=740578&fcc_id=AFJIC-746PRO
Backup copies of both parts of this manual are also available:
http://groups.yahoo.com/group/IC746/files/IC-746pro-Instruction-Manual-1.pdf
http://groups.yahoo.com/group/IC746/files/IC-746pro-Instruction-Manual-2.pdf
Another good place to look for on-line manuals is:
http://www.mods.dk/
Hey, we even found a copy of the IC-746 Instruction Manual in Italian.
http://www.marcucci.it/download/
While Icom has relaxed a little in providing these documents, they are still protected by
copyright. Please, treat them accordingly. Remember, Icom is doing us a favor.
2.8 Are there electronic copies of the circuit schematics?
We know of some for the IC-746-PRO, but not for the IC-746. Check out:
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http://hamradio.online.ru/sch_eng.html
for a wide variety of schematics.
2.9 Are there electronic copies of 746 service manuals?
No such copies are known to exist, although they would quickly become popular if they did.
As of May 2001, Icom had no plans for releasing one. Additionally, Icom considers any
such external productions to be a violation of their copyright. Ray (the product manager at
the 2001 Hamvention) was very firm on this.
Hard copies are available through any Icom retailer as well as through the W7FG Vintage
Manual WWW site at:
http://www.w7fg.com/
2.10 How do I fix the font substitution error in the PDF manual?
When trying to read the PDF version of a 746 Instruction Manual with the Adobe Acrobat
Reader, some people encounter the following three dialogs on page 10 of the document (PDF
page 12).
A font required for font substitution is missing.
An error has occurred that may be fixed by installing the latest version of the Japanese
Language Support package.
Unable to find or create font "Ryumin-Light-Identity-H". Some characters may not
display or print correctly.
The error is not fatal. There are about dozen places in the manual where text in diagrams
will show up as a series of dots.
You can get rid of the error by downloading the appropriate Asian font package directly from
Adobe's support pages. As of November 2001, the appropriate link was:
http://www.adobe.com/support/techdocs/2a156.htm
2.11 How does an IC-746s differ from an IC-746?
Japan has a 3rd Class license that is power limited (sort of like the defunct US Novice class).
The IC-746s is identical to the IC-746, except that it caters to this limited operating class. It's
output power is limited to 10w on HF and 20w on VHF.
Nobody has yet reported a "mod" for this rig to bring its power up.
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2.12 What is the IC-7400?
2.13 What is the IC-746-PRO?
These are both successors to the IC-746. The IC-7400 is the Japanese version while the IC-
746-PRO is the English version. We don't know yet what else (if anything) differentiates
them besides their name.
There are two ways to look at the IC-746-PRO. Some view it as a beefed up IC-746 while
others view it as a watered down IC-756-PRO. On the outside, it looks and operates very
much like the IC-746. The controls are similar enough that you confuse the two. However,
the inside (RF chain and DSP) is more like the IC-756-PRO than anything else.
Here are some features that the IC-746-PRO has over the IC-746:
• 32bit DSP with 24bit ADC
• Selectable digital filters (50+)
• Sharp or Soft filtering (via DSP)
• Digital TPBT
• Manual digital notch filter (in addition to ANF)
• Twinned Digital APF (great for RTTY?)
• DSP based RTTY decoder
• Adjustable digital noise blanker
• Digital TX/RX equalization (instead of analog)
• Digital speech compressor (instead of analog)
• Digital voice recorder
You'll notice how prominently the DSP plays in this rig.
One thing the original 746 has over the 746-PRO is an additional IF stage, thus its TPBT is
actually going through two offset IF filters. The 746-PRO achieves its TPBT via the DSP. It
is argued that the DSP filtering more than makes up for the lack of the extra filter and is more
programmable/flexible. It is counter argued that DSP filtering is not as effective as
traditional IF filtering (the 746-PRO instruction manual even eludes to this) and that
insufficient filtering early on overtaxes the DSP.
Both are excellent rigs and only time will tell just how effective DSP really is. Perhaps
someday Icom will make a rig with both.
Here are some of the features the IC-756-PRO has that the IC-746 does not.
- Dual watch receiver design
- Real-time spectrum scope
Additionally, the IC-746-PRO retains the basic form factor, LCD, control layout, and bonus
2m capabilities of the IC-746.
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Plenty of sales and technical information is available (including downloadable pictures and
brochures) from Icom's WWW site at:
http://www.icomamerica.com/
There is a Yahoo discussion group devoted to the IC-7400, as well as a group devoted to the
746 series in general.
http://groups.yahoo.com/group/IC7400
http://groups.yahoo.com/group/IC746/files/IC-746pro-Instruction-Manual-2.pdf
Icom has not yet made a copy of the IC-746-PRO instruction manual available in electronic
form, however, the FCC has. You can access it and other information at:
http://gullfoss2.fcc.gov/cgi-
bin/ws.exe/prod/oet/forms/reports/Search_Form.hts?mode=Edit&form=Exhibits&application
_id=740578&fcc_id=AFJIC-746PRO
And a nice ham-written synopsis appears at:
http://www.qsl.net/ab4oj/ja7ude/ic7400.html
http://www.qsl.net/ab4oj/icom/ic7400/ic7400.html
2.14 Where can I find info on other Icom rigs?
2.15 Where is info on the 706, 718, 756, 765, 735, ...
This FAQ is devoted to the IC-746. As of November 2001, we do not know of any FAQ's
devoted to other Icom models. However, as of Jan-2002, a project was underway to start
accumulating and centralizing Icom information at:
http://www.qsl.net/icom/
While the coordinators of this list already have their hands full, they would be glad to advise,
help, and collaborate with people interested in maintaining other FAQs.
Much of the generic information in this FAQ is applicable to other Icom rigs, but please, use
common sense when trying to apply it.
For general information on other Icom rigs try:
Icom's WWW site at:
http://www.icomamerica.com/
Icom e-mail discussion group at:
http://www.qth.net/
Usenet newsgroup:
news:rec.radio.amateur.equipment
The Icom Amateur Radio Information Pages at:
http://www.qsl.net/icom/
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The definitive collection of "mods" for all makes and models of amateur radio equipment is
at:
http://www.mods.dk/
Yahoo Groups hosts more than 40 e-mail/WWW discussion groups related or devoted to
Icom equipment. Here are some of the more than 50 Icom related groups there.
http://groups.yahoo.com/group/icomr2
http://groups.yahoo.com/group/ICOMR3
http://groups.yahoo.com/group/ic706
http://groups.yahoo.com/group/ICOM706
http://groups.yahoo.com/group/IC-706Mk2G
http://groups.yahoo.com/group/IC-756PRO
http://groups.yahoo.com/group/ic756pro2
http://groups.yahoo.com/group/IC-Q7
http://groups.yahoo.com/group/IcomRadio
IC-751 information pages
http://www.sweb.cz/ok1fig/ic751a.htm
http://www.qsl.net/ab4oj/icom/751a_pbt.html
http://www.qsl.net/ab4oj/icom/icom.html#IC751A
http://www.piexx.com/cgi-bin/piexx.cgi?p=ICOMProm&cart_id=1452031.27134
http://www.piexx.com/cgi-bin/piexx.cgi?p=ux14&cart_id=4031494.24744
IC-765 information pages
http://www.execulink.com/~dstalk/
Last, but certainly not least, AC6V has a wealth of links and resources on amateur radios.
http://www.ac6v.com/swap.htm
2.16 What articles have been written about the IC-746?
Add Remote Control to your ICOM Transceiver
Hansen, John, W2FS
February, 2003, QST, p.41
Adapt a mundane infrared TV remote to control your rig.
ICOM IC-746PRO HF/VHF Transceiver (product review)
Lindquist, Rick, N1RL
May, 2002, QST, p.72
A product review article
http://www.arrl.org/members-only/prodrev/pdf/pr0205.pdf
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A Microphone Adapter for the IC-706
Davidson, Taylor, N4TD
May, 2002, QST, p.38
Describes a microphone preamp/control project that could be easily adapted to the IC-746.
A Quality Sound Card Interface for ICOM Rigs
Lewis, Bob, AA4PB
March, 2002, QST, p.31
A great way to capitalize upon the ACC ports.
Feedback in
May, 2002, QST, p.78
Solving Sound Card Microphone Problems
Covington, Michael A., N4TMI
June, 2000, QST, p.61
Shows a tiny, phantom powered, microphone preamp
Automatic Amplifier Selection for the ICOM IC-746, IC-736 and IC-706MKII
Transceivers
Hewitt, Paul, WD7S
May, 2000, QST, p.33
Operating via the ACC connector (thus bypassing the SEND relay), this project provides
automatic amplifier keying (with ALC selection) based on the Icom band signal.
An External-Amplifier C ontrol Circuit for the IC-706 MK2
Hauff, Fritz, W3NZ
September, 1999, QST, p.80 (Hints+Kinks)
The IC-706 and IC-746 have nearly identical external amplifier interfaces/issues, so most of
the information is relevant.
A Direct Frequency Entry Keypad for ICOM Transceivers
Hansen, John, W2FS
December, 1999, QST, p.38
Adds an external keypad via a PIC and CI-V.
ICOM IC-746 MF/HF/VHF Transceiver (Product Review)
Wolfgang, Larry, WR1B
September, 1998, QST, p.70
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