Icom IC-746 Faq
Summary of IC-746
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Ic-746 faq icom ic-746 faq frequently asked questions about the icom ic-746 hf/vhf transceiver coordinator dana hoggatt kb9sss kb9sss@arrl.Net copyright (c) 2001,2002,2003 by dana hoggatt, all rights reserved. Page 1 of 113 2003-02-08.
Page 2: Recent Changes
Ic-746 faq 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 itali...
Page 3: Table of Contents
Ic-746 faq table of contents icom ic-746 faq........................................................................................................... 1 recent changes....................................................................................................... 2 table of contents............
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Ic-746 faq 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? ..........
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Ic-746 faq 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 ...
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Ic-746 faq 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 a...
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Ic-746 faq lcd driver transistor replacement .................................................................... 84 poor man's tcxo ................................................................................................ 85 upgrading stock ceramic if filter to a crystal filter ................
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Ic-746 faq page:42 incorrect page reference ................................................................................. 100 page:46 no alc adjustment for either am or fm ..................................................... 100 page:46 speech compressor............................................
Page 9: Administrivia
Ic-746 faq 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 tr...
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Ic-746 faq 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/mail...
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Ic-746 faq 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 ...
Page 12: General Info
Ic-746 faq 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 effor...
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Ic-746 faq 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 1...
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Ic-746 faq 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...
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Ic-746 faq 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 befo...
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Ic-746 faq 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, ic...
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Ic-746 faq 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...
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Ic-746 faq 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.Yaho...
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Ic-746 faq 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....
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Ic-746 faq 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 th...
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Ic-746 faq a product review article http://www.Arrl.Org/members-only/prodrev/pdf/pr9809.Pdf der neue von icom: ic-746 - mit 100w und dsp auf 11 bandern petermann, bernd, dj1to april, 1998, funkamateur, p.392 a product review article (german) a remotely controlled antenna switch thompson, nigel, kg7s...
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Ic-746 faq 2.18 i thought the lcd was blue, but photos show it as green? The screen is blue. The green color that shows up in many photos is caused by the camera flash, sort of an optical illusion. Non-flash photos always show the screen as blue. For an example, see n4wmx's 746 non-pro at: http://ww...
Page 23: Accessories
Ic-746 faq 3 accessories 3.1 power supplies 3.1.1 what power supply should i use with the ic-746? Short answer any good quality, communications grade, power supply rated at least 20 amps or more (continuous duty) should do just fine. However, most of us use larger supplies (for a variety of reasons)...
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Ic-746 faq http://www.Arrl.Org/members-only/prodrev/pdf/pr0009.Pdf transportability the larger the capacity, the larger and heavier the supply. If size and weight are critical for you, consider a "switching" supply as they are usually less than half the size of a "linear" supply. Electrical noise al...
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Ic-746 faq load capacity the size, weight, and cost of a power supply all tend to increase with its load capacity. Those factors encourage us to get the smallest supply we can. There are also factors that encourage larger supplies; such as noise, heat, accessories, etc... The ic-746 specifications l...
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Ic-746 faq everyone would agree that transmitting for 3 minutes at 20 amps till the repeater time-out cuts you off is not a peak. How short a time constitutes a peak and at what duty cycle? Without some sort of specification or standard, "peak" and "intermittent" could mean just about anything. Most...
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Ic-746 faq other and future rigs may have greater power demands (like the 756pro). Extra capacity now may avoid the need to upgrade your supply in the future. You might well spend most of your time in a low power situation (ssb qrp) and get by with less than 5a. But, in an emergency, you and your ge...
Page 28: 3.2
Ic-746 faq 3.2 antennas 3.2.1 what antenna should i use with the ic-746? Short answer any antenna you want. Long answer seriously. Any antenna will work with the ic-746, with the proper interfacing. People have even made contacts using dummy loads. Antennas are probably the most uniquely individuali...
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Ic-746 faq 3.2.2 what range can the automatic antenna tuning unit (atu) handle? Officially, the automatic atu in the ic-746 can handle swr mismatches of up to 3:1 on hf and up to 2.5:1 on 6 meters. In practice, many people get even wider ranges, a few as high as 7:1, but be wary of pushing the atu t...
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Ic-746 faq many people use an external atu along with their ic-746. Usually, they leave the external atu switched to "bypass" and let the internal atu do its thing. For troublesome bands/antennas, they turn off the internal atu and engage the external one. Others use an external atu to match their a...
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Ic-746 faq a possible problem we haven't already mentioned may stem from the possible similarity between the ic-746 and the ic-756. The ic-756 users have been warned not to use either their "auto tune" or "ptt tune" features while on 6m. (even the manuals mention this, although in passing). Several ...
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Ic-746 faq the simple thing to do is to switch modes to either am or rtty briefly. After making your measurement, switch back to ssb. 3.2.12 how do i tune up in cw without a key? Usually you don't. You probably don't even want to be in cw mode without a key. Odds are, you're trying to tune up for a ...
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Ic-746 faq at-180 the at-180 is intended for use in the shack with near-resonant antennas; it will tune a maximum excursion of 3:1. The at-180 was designed for the ham bands only but should have sufficient band overlap to accommodate the mars frequencies. Here are the at-180 specifications: http://w...
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Ic-746 faq connecting and operating an ldg tuner is exactly the same; they even make a cable specifically for the task. Connecting and operating an sgc tuner is almost the same; you'll have to make your own interface cable. Instructions for that are at: http://www.Sgcworld.Com/products/couplers/icom...
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Ic-746 faq 3.2.17 how do i repair the detector diodes in the internal atu? ???? (mike) describes his experience at fixing blown detector diodes in the internal atu. The problem was that the auto-tuner would no longer tune up the antennas that it used to for me, and the swr didn't change on the anten...
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Ic-746 faq page 36 of 113 2003-02-08.
Page 37: 3.3
Ic-746 faq 3.3 microphones 3.3.1 what is the best microphone to use with the ic-746? In theory, your favorite microphone is the best choice, provided you hook it up and adjust it properly. Its basically just a matter of personal preference. The confusion lies in the definition of "best". Most users ...
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Ic-746 faq ohms impendence, and the impedance mismatch will exacerbate the signal level deficiencies. Some microphones operate at much higher impedances (as high as 100k) and, unmatched, will suffer from distortion in addition to signal level problems. Since you're already wiring up a new mic cable,...
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Ic-746 faq another good qst article on microphone preamps is: "adapting the astatic d-104 microphone for use with modern transceivers" qst, aug, 1999, p.34 a copy of which can be found at: http://members.Aol.Com/ampmicro/ another interesting design can be found at: http://www.Muzique.Com/ssm2166.Gif...
Page 40: 3.4
Ic-746 faq 3.4 keyers 3.4.1 can i hook my straight key to the front "elec key" jack? 3.4.2 can i connect my own electronic keyer to the ic-746? 3.4.3 how do i wire up my paddles for use with the internal keyer? Short answer yes, virtually any type of key/keyer can be connected to the ic-746 via eith...
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Ic-746 faq tip ring sleeve oooo ==== ]]]]]]} ---------> 3 cond wire to paddles (dit) (dash) (-) to set the radio to use the internal electronic keyer, you do have to go to the "key", "set" menu and tell it you will be using paddles. See page 23 and page 27 in the operation manual. While in cw mode p...
Page 42: 3.5
Ic-746 faq 3.5 amplifiers 3.5.1 how do i hook up an icom ic-pw1 rf power amplifier? The electrical connections are easy; just follow the diagram at the top of page 79 in your instruction manual. Then carefully read the instructions that came with the ic-pw1 because they can be confusing. Icom has in...
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Ic-746 faq if you introduce additional devices or alternative interfaces (such as the dx4win logging software using the "$10 radio shack" interface, talking to the ic-746 in ci-v address 56h) then the pw-1 can become confused and stop talking to the ic-746. One solution to the problem is to set both...
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Ic-746 faq this continues to be a process of discovery, so i'll present what we know in that form. Instruction manual page 79 of the instruction manual says that the send jack is rated for 16 vdc at 2a. Some rigs have failed while well within those specs. Others seem to survive conditions far in exc...
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Ic-746 faq more searching did turn up information for the sy-12-k relay, which lists a contact rating of 1 a @ 24 vdc or 0.5 a @ 120 vac (resistive). We can infer that the omr-109 specs are most likely less than these. Http://www.Fceu.Fujitsu.Com/pdf/sy.Pdf unfortunately, we still do not have many a...
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Ic-746 faq switching rates explored closer examination of the maximum switching rates reveals a possible problem. Suppose, for example, i transmit at only 1 word per minute. We average 5 characters per word, 3 dit- dahs per character, and 2 switches per dit-dah. So, cw at 1 wpm will generate 30 rela...
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Ic-746 faq are driven by transistor q1302. The transistor is not a hardy as the relay, with obvious consequences. Summary we have now identified many possible failure conditions for the send relay. * too much voltage * too much current (switching or carrying) * v/c spiking from inductive loading * a...
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Ic-746 faq http://www.Qsl.Net/icom/download/fes.Pdf http://johnjeanantiqueradio.Com/gary.Htm you could build a very simple solid-state switcher like: http://www.Qsl.Net/icom/ampcontrol.Html http://www.Qsl.Net/dxlab/amp%20control%20circuit.Jpg 3.5.8 can't i just use the acc port to key my amp? An ico...
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Ic-746 faq http://www.Qsl.Net/k0bx/amp.Html another example is here: http://www.K6xx.Com/radio/ic706amp.Pdf and yet another example: http://www.Yccc.Org/articles/al1200relay.Html 3.5.10 why do i get ic-746 birdies when i turn on my ic-2kl? The ic-2kl is at fault, not the ic-746. A noisy, 12 volt swi...
Page 50: 3.6
Ic-746 faq 3.6 tnc 3.6.1 how do i hook up a tnc to the ic-746? Check out the wiring diagrams available at: http://www.Packetradio.Com/tnc-to-radio.Htm page 50 of 113 2003-02-08.
Page 51: If Filters
Ic-746 faq 4 if filters 4.1 how many optional if filters can i install into the ic-746? There are two (2) slots for optional filters in the 9mhz if, and one (1) slot for an optional filter in the 455khz if. 4.2 what optional if filters are available for the ic-746? Available filters for the 9mhz if ...
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Ic-746 faq the inrad 306 is listed on their www site, and is electrically compatible, but might not fit in the available socket. The icom crystal filters with an "a" suffix (fl-44a, fl-52a, fl-53a) all have 6mm lower case heights than the equivalent filters without the "a". Icom calls them "low prof...
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Ic-746 faq inrad publishes basic performance curves of most of their filters on-line. An example of a typical curve is: http://www.Qth.Com/inrad/graphs/116.Gif ab4oj has a complete set of passband curves for icom's filters on his www site at: http://www.Qsl.Net/ab4oj/icom/filters/filters.Html severa...
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Ic-746 faq 4.9 can an if filter be too narrow? Yes, an if filter can be too narrow, but sometimes, that can actually work to your advantage. We'll describe only a few specific situations as examples. When the if filter's bandwidth is less than the bandwidth of the desired signal, then part of the si...
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Ic-746 faq radio itself. Reported assembly times range from 1-4 hours per filter, depending upon the skill and care of the installer. Finally, some claim that there is an insertion loss to the inrad filters vs. The icom filters. However, it's been demonstrated that dropping the noise level also drop...
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Ic-746 faq starting with both filters in their center, detented, position (widest effective bandwidth), and tune in your desired signal as accurately as possible. Grasping both if shift knobs simultaneously, simply turn and adjust for the best sound. If you have a nearby, interfering signal, then yo...
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Ic-746 faq 4.19 why is there only one optional 455khz if filter slot? Nobody knows for sure, but the most popular speculation is that it made the radio cheaper. 4.20 any tips on installing 9mhz inrad filters? Neatness counts. Good soldering skills are a must. Most of the hams who have installed one ...
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Ic-746 faq 4.23 what are some popular filter combinations? "popular" does not necessarily equal "best". Don't do something just because it's popular. Read the above material so that you can make an informed choice. For example, one of the "best" optional filters for an ic-746 is a 2.4khz wide crysta...
Page 59: Computer Control
Ic-746 faq 5 computer control 5.1 how do i wire the ic-746 up for computer control? 5.2 what cables do i need? 5.3 what are ct-17, opc-478, opc-662 all about? The ic-746 is computer controllable through a serial interface, but it is not rs-232. This is both good and bad. Bad, because you can't just ...
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Ic-746 faq kd6uu posted detailed schematics and instructions on eham.Net: http://www.Eham.Net/articles/1588 and then wrote an excellent updated follow-up article at: http://www.Qsl.Net/kd6uu/icomci.Html designs have been published in both qst and cq magazines. "everything you always wanted to know a...
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Ic-746 faq physically stack the two transistors atop each other with the two emitters twisted together. This helps to keep the volume down. A little heat shrink tubing may help here and there, but use it very sparingly; it adds volume and a smart layout really doesn't require any. Use a highlighter ...
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Ic-746 faq http://www.Geocities.Com/w2eny/civ/ http://www.Geocities.Com/w2eny/icom_cable/ w7fg vintage manuals has listings in their catalog for both the ct-17 level converter and for the ci-v communications interface on their www site at: http://www.W7fg.Com/ 5.7 what is the ci-v address of the ic-...
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Ic-746 faq last word we know of (january 2001), icom had no plans to update/fix/enhance the rs-746 software. Rt systems software ok, so icom refers us to rt systems at: http://www.Rtsars.Com/ however, as of may 2001, rt systems does not have a 746 control program. They told n8avx (in february 2001) ...
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Ic-746 faq xmlog the freeware logging software produced by w1ect also talks directly to the ic-746. You can learn more at either the www site: http://www.Xmlog.Com/ or at the yahoo e-mail group site at: http://groups.Yahoo.Com/group/xmlog tr log one of tr-log's claims to fame is that it will run on ...
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Ic-746 faq http://www.Plicht.De/ekki/software/pme.Html mixw http://tav.Kiev.Ua/~nick/mixw/mixw.Htm 5.10 why doesn't computer software update freq when tuning the 746? Civ transceiver, when enabled, forces the radio to report its frequency whenever you qsy, and to report its mode whenever you change ...
Page 66: Problems and Clarifications
Ic-746 faq 6 problems and clarifications 6.1 what's that funny rattling noise i hear when i first power on? Often, it’s the internal antenna tuning unit. The relays make audible clicking/rattling sounds. 6.2 what's that "click" i hear as i tune across certain frequencies? The clicking noise you hear...
Page 67
Ic-746 faq 6.5 why isn't my output power up at 100 watts? There are quite a few possibilities. Here are a few that have been discovered over the years. Low dc supply voltage. As shipped, the ic-746 really wants a full 13.8 v dc to yield full output power. While the rig can operate at voltages as low...
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Ic-746 faq the rf driver transistors may have failed. The driver stage is common for 2 meters and hf. The two driver transistors (2sc1972) are right under the top cover. You can easily measure the voltage on the basis, or feel the temperature of the 100-ohm basis resistors. 2sc1971 transistors are m...
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Ic-746 faq try setting option 10 “meter peak hold” to give you a better idea of your peak power output. Or better yet, monitor your output on a scope with a standard two-tone test. There are excellent instructions on using an oscilloscope to make pep measurements at: http://www.Qsl.Net/ab4oj/peptest...
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Ic-746 faq the above chart is available on the www at: http://groups.Yahoo.Com/group/ic746/files/ic746-power.Jpg 6.7 the backlight in my lcd has stopped working. What's wrong? Short answer your problem is probably one of the display driver transistors on the s-logic board behind the display. It will...
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Ic-746 faq variable by the dimmer function on the radio, then this transistor is probably ok. Q303 and q304 are the next most likely candidates. These 2 transistors are in push-pull configuration to drive the x-former (base is 180deg phase shift by the x-former) refer to pages 6-1, 9-1, 10-1, and 11...
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Ic-746 faq no dust behind the plastic screen is a pain. Get yourself a small can of workshop compressed air or co2 if you can. Vk4tzl (glenn) reports: "the actual repair is relatively easy...Assuming that q302 is the problem. The whole repair took me one hour. Removing the front panel from the radio...
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Ic-746 faq while we can't yet prove the above assertion, data compiled by wa0kwk from voluntary usage reports (brightness level, operation time, problems and repair, etc...) would seem to support the theory. The raw data is at: http://groups.Yahoo.Com/group/ic746/database?Method=reportrows&tbl=2 of ...
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Ic-746 faq http://www.Farcircuits.Net/dtmf1.Htm have some circuits that might be adaptable. Perhaps someone could base a design upon the ns tp-5089? Http://alds.Stts.Edu/datasheet/dtmf/ns-tp5089.Pdf http://www.Boondog.Com/%5ctutorials%5cdtmf%5cdtmf.Htm another approach is to let your nearby pc gener...
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Ic-746 faq while nobody has figured out what the band edge beeps correspond to, we have been able to rule out several possibilities. They do not correspond to the amateur radio frequencies in japan. For that matter, they do not correspond to the ham allocations in any of the iaru regions. They are n...
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Ic-746 faq 6.15 how do i adjust the lcd display? Page 66 of the instruction manual describes how to change both the lcd contrast and the lcd backlight. Push menu to select m2. Push button to select lcd. Push buttons to select lighting or contrast. Turn the tuning knob to adjust value. 6.16 the noise...
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Ic-746 faq 6.17 how do i get rid of ignition noise? Someone should write a book on this topic. (oh wait, someone did, see below) here are some of the suggestions that have been made in the past. • clean the battery contacts • run the power leads inside a grounded shield (possibly an old coax braid) ...
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Ic-746 faq the ic-746 service manual does have an adjustment procedure for the nb on page 5-10. Icom tech support provided w7gj with a pdf copy of that page around jun-25-2001. That pdf file is now available from several places. Http://www.Bigskyspaces.Com/w7gj/ic-746.Pdf http://groups.Yahoo.Com/gro...
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Ic-746 faq local: (602) 371-0555 fax: (602) 371-0522 paul hanson & associates paul hansen & associates 2411 robert nash ct. Tucker, ga. 30084 phone: (770) 939-1320 houston amateur radio supply george phone: (281) 355-7373 while not "authorized" by icom, the following repair shops have excellent repu...
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Ic-746 faq phone: (770) 939-1320 tim moes email: tcmmoes@yahoo.Com watertown, sd radioworld http://www.Radioworld.Ca/ email: service@radioworld.Ca 4335 steeles ave w. Toronto, ontario canada, m3n 1v7 phone: 416-667-1000 fax: 416-667-9995 and of course, you could always just run down through the list...
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Ic-746 faq 6.23 why does the s-meter seem low on 2m fm? While this is apparently common on many modern multimode rigs, we do not know precisely why. The s-meter sensitivities published in the qst product review did not show a problem on 2m. (6m is a different story, but nobody seems to complain abou...
Page 82: Modifications
Ic-746 faq 7 modifications 7.1 what tx/rx "mods" are there for the ic-746? "mod" is slang for "modification". Most people who ask about modifying their radio are looking for ways to make the ic-746 transmit or receive additional non-amateur rf bands. The 746 already has general receive coverage from...
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Ic-746 faq safe 2m tx/rx sequencing ah6le has modified his ic-746 to provide safe sequencing for eme work. Http://www.Ah6le.Net/radiomods.Html simple cat interface ok2wy has a "simple cat / programming interface for icom rigs". Rumor has it that he has also designed an in-board step attenuator. Http...
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Ic-746 faq dielectric. This will make it a lot easier to construct the input and output cables without melting insulation. The male pc connector is designed for crimp termination, but it can be soldered as well. I just stripped the center conductor of the coax and (carefully) soldered it into the ce...
Page 85
Ic-746 faq poor man's tcxo n0uk (chris) came up with a "poor man's" tcxo that substantially reduces frequency drift, particularly for 2m. He discovered that the cooling fan, which runs during transmit, draws air right across the local oscillator. The resulting temperature drop causes the lo to drift...
Page 86
Ic-746 faq most hams feel that raising the rf output power above 100w is a bad idea for a variety of reasons: • you can exceed the power ratings on the output transistors. Even if they don't blow out right away, they can eventually due to the long-term electrical and thermal strain. There's nothing ...
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Ic-746 faq removing the bcb attenuator a few folks have noticed that the ic-746 is less sensitive below 1.6mhz. This appears to be due to an additional attenuator being switched in to protect the first rf amplifier from overload by comercial broadcast transmitters. Some theorize that removing the ex...
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Ic-746 faq wd7s wrote an article for the may 2000 qst entitled "automatic amplifier selection for the icom ic-746, ic-736 and ic-706mkii transceivers". Hewitt, paul, wd7s may, 2000, qst, p.33 k6xx has similar circuitry described on his www site at: http://www.K6xx.Com/radio/icbsciv.Html another copy...
Page 89
Ic-746 faq unmuffling icom hand mics w0vd had problems with muffled audio; so he opened up all of his icom hand mics and removed the heavy wad of felt that was in front of the mic elements. He's receiving much better audio reports now. The felt was probably there to prevent "popping" from consonants...
Page 90: Misc...
Ic-746 faq 8 misc... 8.1 are there different versions of the ic-746? Yes, there are at least two distinct versions of the ic-746. While most of the indications are circumstantial, one definitive piece of evidence are the two different procedures for modifying the transmit/receive range. Another defi...
Page 91
Ic-746 faq 8.4 what are the pin-outs on the acc-1 connector? Page 72 of the instruction manual has the full scoop. Here is a brief description. 1 rtty high > 2.4 v dc low current 2 gnd 3 hsend input/output for hf-6m when grounded, transmits goes to ground when transmitting ground level: -0.5 to 0.8 ...
Page 92
Ic-746 faq 8.5 what are the pin-outs on the acc-2 connector? Page 72 of the instruction manual has the full scoop. Here is a brief description. 1 8 v 2 gnd connected directly to pin 2 on acc-1 3 hsend connected directly to pin 3 on acc-1 4 band band output voltage varies from 0 to 8 v dc 7.5 v 160m ...
Page 93
Ic-746 faq bux commco sells equivalent cables/connectors that are cheaper. You can find more info at: http://www.Buxcommco.Com/ better solution rather than finding another icom connector, many folks put inexpensive connectors on the cables of all their rigs and power sources. That way they can use a...
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Ic-746 faq "hi-fi ssb" audio is a hot topic within ham radio. Everyone wants the best transmitted audio they can get, however, not everyone agrees upon what "best" is. The issues become even more heated once you add concerns over excessive bandwidth usage and splatter. The characteristics/capabiliti...
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Ic-746 faq 8.12 how does one improve transmission fidelity? Here is a checklist of several possible actions (not in any particular order). • using tcn, set the "ssb tx tone" control to h. (ssb tx tone affects all voice modes) • turn off comp (compression). • use a higher quality microphone. • use mi...
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Ic-746 faq 8.15 how do i adjust the 746 for best am performance? The 746 performs well on am for general communications. However, many operators choose (and fall in love with) am for the sound. For this, the 746 can fall a little short of expectations. Start by improving your audio fidelity as descr...
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Ic-746 faq 8.18 how do i program a non-standard repeater offset? Repeater offsets are just a special (convenience) case of general "split" operation. If you need to set up such a repeater without changing your default/normal offset, then here's what you do (as outlined on page 35 of the instruction ...
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Ic-746 faq 8.20 how do “zero-beat” a cw signal? Zero beating ensures that your cw signal is being sent at exactly the same frequency as the received signal. First, make sure that rit is turned off. Then, use one of the following two techniques: • adjust the frequency of the radio to where the pitch ...
Page 99: Instruction Manual Errata
Ic-746 faq instruction manual errata know errors in the instruction manual, by page number. Page:2 incorrect page references (12) af control references p.12, should be p.11 page:6 external speaker and remote interface jacks are swapped. Page 6 has the external speaker and computer remote connectors ...
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Ic-746 faq page:27 only one bar for cw sidetone level, not two in the cw -> key -> set menu, there are 2 options that control the cw sidetone: options 1 and 2. Option 1 sets the sidetone level via the displayed bar. However, option 2 is only an on/off setting; there is no level bar (contrary to what...
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Ic-746 faq page:53 enter numbers via keypad, not tuning dial while the diagram specifically highlights the numeric keypad on the radio; the "instructions" fail to mention that numbers and the decimal point are entered via the keypad instead of the tuning knob. Page:56 incorrect page references in th...
Page 102: Service Manual Discrepancies
Ic-746 faq service manual discrepancies the "service manual" is supposed to be the best, final word on the electronics within the ic- 746. However, the data it contains isn't always consistent. Here are the known discrepancies. Identity of q302 q302 on the s-logic board is a driver transistor for th...
Page 103: Glossary
Ic-746 faq glossary here are short expansions of some of the more common acronyms you'll encounter when reading about the ic-746. This document is not a dictionary; these are not definitions. A more comprehensive and detailed listing of terms can be found at: http://www.Qrz.Com/i/hamspeak.Html acc a...
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Ic-746 faq rit receiver incremental tuning rtty radio teletype rx short for receive or receiver ssb single side band swr standing wave ratio tcn tone control - ssb transmit cutoff tcxo temperature compensated crystal oscilator tpbt twin pass band tuning ts tuning step tx short for transmit or transm...
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Ic-746 faq contributors + acknowledgements there are two kinds of contributors to this faq: direct and indirect. Direct contributors have written entire passages that have been incorporated nearly verbatim. Sometimes, they are specifically authoring something with the faq in mind. Also, they are ind...
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Ic-746 faq kj6h tod kk5dr matt e. Kt0k greg brown kt3d dennis f. N0at ron n0gmp dave n0rc rod cerkoney n0uk chris c. N1ege steve n1jm john merrill n1lf les rayburn n1zqu sean n3jja jim nuytens n4aiw fred n4tj tom johnson n4umj eddie bryant n4wmx robert n5nw marty n5pht gary stone n6tgk stephen m. N7...
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Ic-746 faq wn2sqc ken wu1t damon c. Sv1ens ?? Greece mike foerster if anything, then the sheer number of people involved (more than 100 contributors from more than a dozen countries) should illustrate the collaborative effort involved in producing this faq. Thanks to everyone involved. Page 107 of 1...
Page 108: Disclaimer & Copyright
Ic-746 faq disclaimer & copyright this article is provided as is without any express or implied warranties. While effort has been taken to ensure the accuracy of the information contained in this article, the author and contributors assume no responsibility for errors or omissions, or for damages re...
Page 109: Revision History
Ic-746 faq revision history 2002.11.26 added q/a on quadra amp hookup 2002.11.25 updated info on band decoders 2002.11.22 more info on researching rig prices 2002.11.20 more info on lcd repairs 2002.11.19 added/updated article information 2002.11.19 more info on ct-17 interfaces 2002.11.19 added mor...
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Ic-746 faq 2002.06.03 added q/a on non-standard repeater offsets 2002.06.03 updated info on internal+external atu usage 2002.06.03 corrected amplifier question numbers 2002.06.03 added q/a about 100% duty cycle 2002.05.06 added a few more www links 2002.04.20 added another magazine article 2002.04.0...
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Ic-746 faq 2002.02.01 added m/e p:19 - ssb tx tone affects am/fm 2002.01.31 added q/a about cap/mars compliance 2002.01.31 added q/a about future of faq 2002.01.21 updated info on 746 net 2002.01.12 rearranging and updating "mods" info 2002.01.11 added info on "cordless headset" mod 2002.01.10 teste...
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Ic-746 faq 2001.10.30 added q/a on ic-746s 2001.10.24 added q/a on multiple keyers 2001.10.24 started a small glossary 2001.10.23 clarified q/a about heil mic adjustments 2001.10.23 added q/a about dynamic microphones 2001.10.22 updated info on different versions 2001.10.21 added info on acc pin-out...
Page 113
Ic-746 faq page 113 of 113 2003-02-08 2001.05.25 more information on power supplies 2001.05.24 added q/a about dtmf tones 2001.05.23 added q/a about numeric programming 2001.05.22 added q/a about antennas 2001.05.21 added q/a about electronic manuals 2001.05.20 updated info on rig modifications 2001...