Rig Woes
Alan Applegate (K0BG)
on
June 12, 2005
View comments about this article!
In recent weeks, I have seen several posts on eham.net regarding the Icom IC-706 series radios. These posts included requested information on wiring aftermarket microphones replete with an RJ45, powering ancillary equipment from the accessory and/or ‘tuner’ port, and amplifier switching. Since I have lived with several different Icoms of recent, I decided to publish this article in hopes of quelling some enthusiastic amateurs from making the proverbial $300 mistake.
While the following is directed toward the Icom IC-706 series, it can be applied to several other models and makes of radios. I admit that some (not all) of this is based on experience, and some of it on the very expensive lessons of others. In any case, if it saves just one luckless amateur, the effort was worth it.
I have responded to many posts dealing with replacing the stock microphone with an amplified one like a D104, and always in the negative. There are several very good reasons for this. Probably one of the best articles I have seen on this subject was published in these very pages, and written by Steve Katz, WB2WIK/6:
http://www.eham.net/articles/8069. Anyone contemplating such an endeavor, should read this article first. There are, however, a couple of other good reasons not to try it.
Every one of Icom’s various radios has 8 volts imposed on the microphone hot lead through a 100-ohm resistor. In addition, one of the pins has a direct connection to the 8-volt regulator. Shorting either of these to ground will result in failure of the 8-volt regulator--a very expensive fix!
With respect to the IC-706, the microphone jack is an RJ45 but not just an ordinary RJ45. There are some 40 different configurations of RJ45 male plugs. Some for solid wire (ethernet type), some for stranded wire (Icom 706), some for flat, silver satin telephone wire, and some for round wire. Those for the latter have a special strain relief, and are slightly longer than the telephone types. There are three different crimp tool dies required to accommodate them all. The crimping tool sold by Radio Shack is not adequate for any one of them except the flat ribbon type wire. And that is not all.
I don’t consider myself fat fingered, but I still have problems assembling the plugs. A good amount of manual dexterity is required to correctly place the wires in the RJ45, and correctly place the plug into the crimping tool. If you do it incorrectly, it could cost you a bundle to replace the 8-volt regulator. One recent poster’s 706 went into a scan mode when an aftermarket headset was plugged into it. This fact exemplifies how easy it is to make a mistake.
The rear panel of the IC-706 is just as inviting. The accessory jack, and the ‘tuner’ jack both have the nominal supply voltage inclusive on their pin outs (I’ll cover the ‘tuner’ jack in a moment). Pin 1 of the accessory socket of the IC-706 is 8 volts and it is directly connected to the regulator. It will fail instantly if this line is shorted to ground. If you think the RJ45 is hard to wire, wait until you try the accessory plug. And speaking of the accessory plug, Icom includes it with the radio. The wires are pre-attached via a short pigtail complete with the wires already stripped. Don’t even think about using it without properly sleeving these pigtails to prevent shorts.
Pin 8 has the nominal supply voltage applied, except it is about one volt lower than supply with no load, and about 2 volts lower at its rated maximum of one amp. Depending on the device(s) connected to this pin, it may or may not work as advertised due to the low voltage. This includes any device that uses the supply voltage and/or the band output voltage to remote switch an amp or antenna switch when the radio is operated mobile.
Pin 5 is the HSEND line. It goes to ground when the radio is keyed, or if taken to ground the radio transmits. Since the maximum sink current is 20 mils, it cannot be used to directly key an external amp. This is why an Ameritron ARB-704 amp interface or similar device is a recommended accessory. There is a caveat with this too if you’re operating mobile. You can’t use pin 8 (nominal supply voltage) to power the ARB-704, because of the inherent voltage drop through the radio. In other words, if must be directly connected to the supply, and not switched through the radio.
Some folks try to circumvent this by connecting the ARB-704 directly to the supply by using pin 1 of the ‘tuner’ port. Aside from the aforementioned voltage drop, shorting this pin will cause the switching transistor to fail, usually by shorting out. This will cause the circuit board trace to fail before the internal fuse blows. Now we’re REALLY talking repair moneys.
I have to say, there are a lot of amateurs who use the various accessory I/Os correctly, and without mishap. This is usually a result of purchasing ready-made devices and/or cabling. Bob Lewis, AA4PB (http://www.ham-kits.com), sells several different interfaces, which utilize the aforementioned ports to trick an SGC auto-coupler in thinking an AH-4 is connected instead. The difference is, they are well engineered and tested. There are several companies making tuning aides, which also use the ports. In other words, you can use them effectively, but you’ve just got to know their limitations, and yours!
Alan Applegate, K0BG
www.k0bg.com
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Rig Woes
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by W9GB on June 5, 2005
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Unfortunately, most amateurs have very little knowledge of Telecom and Electrical standard bodies (IEEE, IEC, USOC, NEMA, EIA/TIA) or correct terminology usage these days.
The "no one left behind" approach - or "dumb down" exams - does not increase the typical amatuer's practical knowledge of the current state of communications.
The Universal Service Ordering Code (USOC) system was developed by the Bell System and introduced by AT&T® in the 1970s to connect customer premises equipment to the public network.
These codes, adopted in part by the FCC, Part 68, Subpart F, Section 68.502, are a series of Registered Jack (RJ) wiring configurations for telephone
jacks that remain in use today.
http://www.blackbox.com/tech_docs/tech_overviews/usoc.html
So, the USOC codes were used for "work orders" to technicians (or sub-contractors) to assure that the jack would be installed and configured in a standardized and consistent manner.
This was a crucial "first standard" after the landmark legal rulings in the late 1960s and 1970s forcing AT&T to "open its telephone network" for the "interfacing" of third-party equipment (e.g. answering machines, non-AT&T telphones, alarm systems, radio autopatches, etc.).
So, the term RJ-45 is actually a specific USOC wiring CONFIGURATION for an 8-pin modular jack (telecom usage) - and is NOT referring to the 8-pin modular jack itself.
Greg, w9gb
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Icom Engineering Standards
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by HA5RXZ on June 12, 2005
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OK, firstly, thanks for giving all of these technical details. Hopefully this will prevent some dead Icom rigs and their associated repair bills.
Now.
1) Who is the idiot within Icom who decided that using an RJ45 type connector on the front panel was a good thing? These plugs are a pain in the butt to wire up and are not resilient enough for normal operation, they are designed to be plugged into a network rack and kept there.
2) Who is the idiot within Icom who decided that placing an unfused 8 volt connection on the microphone socket was a good idea? I know that these modern mobile rigs are packed full inside but even a thermal fuse would save the day. I don't own one of these rigs but would someone knowledgable in these things care to put up a modification so we can correct the manufacturers mistake?
3) Who is the idiot within Icom who decided that placing an unfused connection on the accessory sockets was a good idea? See comments in (2) above so that I don't repeat myself.
4) Who is the idiot within Icom who decided that a line indicating that the rig was in transmit should only be able to sink a few ma? A power FET is about the size of my fingernail and can sink an amp or two, I'm sure that could squeeze one in somewhere.
My first rig was an Icom, my first multi-mode rig was an Icom and I used to be a fan of their products. If this is an indication of their current engineering standards they will not be getting my business again.
HA5RXZ
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RE: Rig Woes
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by KR4WM on June 12, 2005
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From experience:
1.A D-104 wired to an Icom 735 (my first radio) completely carbonized one of the inductors just inside the radio. It worked well enough that I did not realize it was damaged (with a D-104) but when I reinstalled the factory microphone in order to sell the radio, it was no longer working. Naturally, connecting the D-104 back up "fixed" things. I blamed the microphone as being bad. Further investigation found the burned inductor. After replacing it, things worked fine.
2. Plugging a "Y" adapter into the rear panel power port of my Ten Tec Orion for the purpose of powering the light bulbs in my tuner and a factory optional heat sink fan made an awful raspy buzzing noise on certain frequencies in the receiver. Since I hooked all this up immediately after the radio arrived, I never took the opportunity to test the radio without the cooling fan. This caused me to arrive at the "obvious" conclusion that there was some "factory defect" in the radio. After paying for two or three trips back to the factory (and keep in mind, you have to remove the fan so the radio will fit back in the box, so the technicians never tested the radio with the fan connected to it), I stumbled upon the cessation of the noise when I forgot to plug in the cooling fan when I reassembled my shack! When I plugged it in with the radio turned on, the noise immediately returned! DOH! There was _NOTHING_ in the owners manual telling me not to use this power port to run a fan- and why is it so conveniently located if it can't be used to power a *factory* fan option??? The cooling fan's wires are _just_ long enough to plug into that power port too! A phone call to Ten Tec verified that I should not have plugged the fan into this power port. Why? This should have been caught in engineering, but wasn't. Hooking the fan directly to the power supply cured the problem. The wires attached to the fan should have been 3 or 4 feet long and a warning placed in the box to ONLY connect the fan directly to your power supply.
The moral of the story is- things that seem obvious are not always thusly so.
-KR4WM
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RE: A.O. Rig Woes
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by WA6BFH on June 12, 2005
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So far reading both this article, as well as the responses to date, is like reading the first premises contained within a Michael Chrichton novel. I have more to add but, I’m sure that I will have more fun, and probably make better useful points by waiting awhile!
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RE: A.O. Rig Woes
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by KG4RUL on June 12, 2005
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I have to include RJ45 connectors (my FT-100D has one) in the same category as those damn SMA connectors on HTs! But, I can understand the engineering rationale for both devices - SIZE! As electronic devices get smaller, their interfaces to the outside world (key pads, switches, connectors, etc.) have to get proportionately smaller.
Unfortunately, the RJ45 is meant to be used in a environment where it is plugged in and left alone. Similarly, the SMA is not meant for frequent (un)matings that occur in real-world usage. And HT keyboards are not meant for human fingers.
So, let's lobby the engineers for SO239 connectors on our HTs along with keyboards the size of those used with an IBM PC. Let's have them put MIL-STD connectors on mike, power, speaker and other connections. They will be sturdy but, not very compact, portable or even good to look at.
Dennis KG4RUL
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Used 706 MKIIGs
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by W4XKE on June 12, 2005
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I have been tempted greatly by the many 706 MKIIG ads on classifieds boards. After reading Alan's article, I'm not so tempted to buy a used Icom! Thanks for the "heads-up" on these potential problems! Respectfully, Johnny, W4XKE
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RE: Used 706 MKIIGs
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by WB2WIK on June 12, 2005
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Nice writeup, Alan.
I think the problem started way before IC-706s were invented. I remember lots of ham, including me, wanting to turn a DX-20/HQ110 into an S-line and doing every possible modification short of engraving the Collins emblem on the panels to try to get there.
But back then, a poorly done mod probably didn't cause the rig to blow up, and if you had done a mod poorly and tried to sell the rig, the buyer wouldn't offer you much for it after seeing it.
Now, we have people turning FT-817s into FT-1000Ds, doing a crappy job, and dumping the gear on eBay.
WB2WIK/6
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RE: A.O. Rig Woes
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by K1CJS on June 12, 2005
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"I have to include RJ45 connectors (my FT-100D has one) in the same category as those damn SMA connectors on HTs! But, I can understand the engineering rationale for both devices - SIZE! As electronic devices get smaller, their interfaces to the outside world (key pads, switches, connectors, etc.) have to get proportionately smaller."
My friends, it is not only size that prompts the useage of these connectors it is, above all, COST! Look at the older mic connectors--bakelite or plastic and a metal barrel with a cord clamp on it. It is undoubtedly cheaper (both cost wise and otherwise) to use a bit of plastic with a few wires imbedded in it than those older connectors. Likewise the antenna connectors on the HTS--it is far less costly to use a knurled threaded barrel and a threaded stub than a mating male and female BNC connector.
Some say the prices of radios have come down over the years, and it is evident--in the parts used to make the radios.
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Rig Woes
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by K7VO on June 12, 2005
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Alan, thanks for another excellent article. What it really comes down to is that you absolutely, positively have to do your homework before doing any modifications or interfacing two pieces of equipment from different manufacturers. Most of the errors (and expensive repairs) come from one of two things: 1) Charging ahead without adequate reading and research, and 2) Not being conscious of one's own limitations.
I, like many posters, dislike RJ-45 connectors on microphones. I have experience assembling them (making computer network cables at work in the past) and I know the different types and I even have the right tools. I know I can do it right and I *still* don't like them.
My brand new (bought at Dayton) Ten Tec Argonaut V still uses the old fashioned 4-pin round microphone connector. I appreciate that Ten Tec still uses the KISS principle on things like this. It takes real skill to mess up a 4-pin round mic. connector if you know how to solder. My Tokyo Hy-Power HT-750, introduced in the early 90's and sold until last year, used an old fashioned speaker/mic. connector for their HF/6m SSB/CW HT. You really don't need more connections to have a mic. that works.
I understand the convenience of having a mic. that can control the radio. How many Icom HM-56As and HM-103s have failed? Many? Most? Sometimes more gadgetry is just plan a bad idea.
Oh, BTW, easier tests aren't to blame. I was ignorant as a new ham under the old testing regime and I learned. The same happens today. Many oldtimers don't keep up on new technology and new standards either and they passed the old style tests. The reason people don't know is because they don't take the time to learn. Often they learn the hard way, with the $300+ repair Alan describes.
72/73,
Caity
K7VO/8
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RE: Rig Woes
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by KL0AN on June 12, 2005
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Nice call on the license thing Caity. I'm SO tired of hearing about the dumbing down of our hobby based on how people get thier licenses.
As for the microphone connector on the 706, I have 2 Icom 706's that I've bought used and both have the original mics with original connectors. I don't really see the need to modify this rig with a more powerful mic, in fact, I had to adjust the gain down a bit on mine. I guess some people just can't leave well enough alone.
My microphones get used quiet a bit, one riding in my snow plow truck and the other in my wife's Expedition. I think keeping the detachable faceplate in a location where it won't get hit all the time is the first step in the connection lasting a long time. My mics have been used in temps of -40f where the display on the poor radio has to warm up so you can see it and the mic cord is like hard rubber, still no problems. I'm almost considering picking up a 3rd 706.
73
Paul
kl0an
Anchorage, AK
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RE: Rig Woes
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by AC0H on June 12, 2005
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Excellent article. This is what I want to see on E-Ham.net. Not the mindless drivel and back biting.
I don't own an 706 and don't forsee purchasing one. It seems to me that the ONLY reason Icom and the others switched to RJ-45's was cost. The actual RJ-45 jack isn't appreciably smaller than the PC mount 8 or 4 pin connectors of old. I haven't noticed any of the $2000 and up HF rigs using an RJ but suspect it will come. Wouldn't it be ludicrous to spend big bucks on a new rig only to be presented with a cheap connector?
Contrary to voiced opinion I really don't mind doing my own RJ's when I have to. You do several hundred of them and it gets to be like tying your shoes.
I have my own gripes with Icom.
If I want to program my 2720 with a computer I have to take a laptop out to the truck, or buy a ridiculous "kit" that comes with the required 20" interface cable between the head and radio, along with a bracket I'll never use.
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RE: Rig Woes
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by AG4RQ on June 12, 2005
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K0BG states:
“Since I have lived with several different Icoms of recent, I decided to publish this article in hopes of quelling some enthusiastic amateurs from making the proverbial $300 mistake.”
“Every one of Icom’s various radios has 8 volts imposed on the microphone hot lead through a 100-ohm resistor. In addition, one of the pins has a direct connection to the 8-volt regulator. Shorting either of these to ground will result in failure of the 8-volt regulator--a very expensive fix!”
I agree with K0BG, the author of this article. I found this out the hard way with my first HF rig, an Icom IC-730, when I tried to wire a D-104 to it. I heard a click (the sound of a semiconductor self-destructing), smelled a little bit of smoke and my IC-730 was now a doorstop. I shorted the 8V regulator to ground. Strangely, the radio still received and transmitted – but on only one frequency per band. The VFO was gone. It became a parts radio. Coincidently, this was a $300 mistake. I had bought the 730 for $300 at the time.
I use the hand mic from the 730, which is an HM7 on my IC-718. The HM7 mic works quite well on the 718. I wouldn’t dare to try to wire the D-104 to my 718. I’m content to stay with the HM7, which performs better than the 718’s electret HM-36 hand mic.
K7VO states:
“Oh, BTW, easier tests aren't to blame. I was ignorant as a new ham under the old testing regime and I learned. The same happens today. Many oldtimers don't keep up on new technology and new standards either and they passed the old style tests. The reason people don't know is because they don't take the time to learn. Often they learn the hard way, with the $300+ repair Alan describes.”
Regarding Caity’s point, I don’t consider this a licensing issue, and it has nothing to do with someone’s failure to take the time to learn. I have a formal education in electronics and radio communications. I was a radio tech, and used to hold an FCC Second Class Radiotelephone license. You could say that I should have known better. Anyone can make a mistake and blow a radio sky high. I learned from my mistake with the 730 and won’t repeat it with the 718.
Thank you Alan (K0BG) for forewarning others not to make this mistake. I wish I could have read a thread like this before I tinkered back in 2000 and made a working radio into a doorstop.
Oh, and BTW, I have one of those stupid telephone jack type mic connectors (RJ45) on my dual band VHF/UHF IC-2340H. When the cheap plastic retainer broke off the connector, it cost me $35 for a new mic cord. If the rig had the standard 8-pin screw-on connector, ordering a new mic cord wouldn’t have been necessary. I would never buy another radio with a connector like that again!
AC0H states:
“Excellent article. This is what I want to see on E-Ham.net. Not the mindless drivel and back biting.”
I agree 100%. The mindless drivel and backbiting is the reason why I seldomly post to any threads on eHam anymore. I will usually just answer elmering questions and stay away from the kinds of articles that are prone to endless heated debates and mudslinging. I don’t even waste my time reading any of that junk anymore.
73 de Mark
AG4RQ
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Rig Woes
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by KE4ZHN on June 12, 2005
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Good article and information. After reading this, one has to wonder why the engineers didnt design some sort of protection for these accessory pins with low voltage on them. Perhaps money wise, this is what the designers figured. Its cheaper to just warranty rigs that get blown up by mistake rather then add some protection on many thousands of radios. And rigs that get fried out of the warranty period, Icom gets to make a tidy little profit repairing these things. Either way, we as the consumer lose on this one. Amateur radio isnt the only thing that suffers from this mentality of producers of manufactured goods. Quality always suffers to profitability.
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RE: Rig Woes
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by KF4VGX on June 12, 2005
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I have my own gripes with Icom.
If I want to program my 2720 with a computer I have to take a laptop out to the truck, or buy a ridiculous "kit" that comes with the required 20" interface cable between the head and radio, along with a bracket I'll never use.
....................................
Amen ! it's a bit pricey also !
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In fairness...
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by KZ1X on June 12, 2005
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The 8P8C (often called an RJ-45) connector is capable of being put on PC boards via automated processes. It is smaller than the round 'Foster' type connector, yes, and less costly as a component also. But the primary reason it's used is the ability to be assembled by automated equipment. This translates to a higher quality product and lower cost to the customer.
There is a huge engineering / marketing challenge to building ham rigs. Traditionally, some fractional percentage of hams will want to make non-factory-optioned connections to their radios, and ironically, the less expensive the radio, the more people will want to dig into it!
Trouble is, it's VERY complicated and costly to make a sophisticated circuit idiot-proof when making it accessible to the outside world AND it's even worse to try and make such connection available using human-usable connectors.
As a design engineer, if given the choices faced by Icom as described in this thread, I'd have made similar choices to theirs. Example: It's beyond the scope of the product requirements to be able to source 8V at xx mA to the mic jack, with an auto-reset polyfuse and have the circuit also 'safe' from INPUT voltages, et cetera; if they did that, the interface circuit would be more complicated than the receiver!
No, it's not perfect, but the world isn't, and learning one's own knowledge and skill limitations can be a costly process. (Ever crash a car? Why?)
As in all human interactions, try to put yourself in the other guy's shoes: mechanical and electronic designs are a series of tradeoffs. You can't blame someone (or a whole company) for making what are reasonable choices in view of the known variables.
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Rig Woes? I like my Icom IC-706mkiiG!
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by VE7ALQ on June 12, 2005
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I have several Icom IC-706mkiiG transceivers, two Icom AT-180 fully automatic antenna tuners, and an ARB 70412 buffer to my Yaesu FL2100z (twin 572B tube) linear. I have the ACC going out from the back of the IC-706 to the AT-180, and daisy-chained off the second ACC connector in the AT-180 I have a cable going to the ARB 70412. Everything is pulling the ACC 12 volt line. No problems. I have the IC-706 output going to the AT-180 which then either goes directly to the antenna, or is deselected (momentary punch of the "Tune" button on the IC-706) to use the IC-706 with the kilowatt amplifier. Thus the AT-180 does not see high power, and the Yaesu FL2100z, having a "PI"-network is capable of matching quite a range in VSWR without resort to an outboard tuner.
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RE: Rig Woes
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by KL7IPV on June 12, 2005
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I agree the RJ-45 is a lousy connector but I haven't had any problems using them nor adding mikes using one I added. In the same vein as the small jacks and parts, there seems to be no protection for a momentary reverse voltage on the power plug. It MAY fail if hit with 12NEG/POS DC where it should be POS/NEG. The 703 I just sent to Icom for repair (I expected it to need repair when I bought it) showed that someone hit it with the wrong polarity voltage and took the PA and transformer out. The radio was still new but the guts were gone. Not $300 but the idea is the same, one needs to know what and how before they plug these little guys in....or PHOOM - it is history. Great article and timely.
73,
Frank
KL7IPV
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RE: Rig Woes
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by AC0H on June 12, 2005
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<<"But the primary reason it's used is the ability to be assembled by automated equipment. This translates to a higher quality product and lower cost to the customer.">>
The PCB mount 8 pin mic connector that came with my Elecraft K2/100 is fully installable by machine. I can guarantee the 8 pin mic connectors on all modern HF rigs were installed by machine, save the connector on my K2. I put it there manually.;-)
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Rig Woes
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by WA2JJH on June 12, 2005
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YIKES ALLEN.....thanks for warning. Many of us have made purchases and mods that went poof.
I am finding there is simple much "BAD" third party electronics around. Ham radio epecially.
Every ham should come foward with possible product
warnings. If a pattern is clear, do not let others allow faulty merchandise into their shack.
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Woes Me
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by WA6BFH on June 12, 2005
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I just loved the references to putting a D-104 microphone on an Icom IC-706! Doesn’t the IC-706 want to see about 500 or 600 Ohms from the microphone?
Also ya know, Astatic made a microphone in the same era as the D-104’s that had the audio roll-off designed for SSB. Everyone really loved “the look” though of that D-104!
The D-104 was a good microphone, for high level “AM”, and a transmitter that wanted to see Hi-Z
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Rig Woes
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by AD5KL on June 12, 2005
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I've had this in the back of my mind for a bit, glad to be forewarned. I have a 718 that I was looking to wire up my old D-104 (from way back in my Children's Band days.)
Guess I'll just hang with the stock mic for a while, or pick up a Heil.
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Rig Woes
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by WA1RNE on June 12, 2005
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>>> I have responded to many posts dealing with replacing the stock microphone with an amplified one like a D104, and always in the negative. There are several very good reasons for this....... Anyone contemplating such an endeavor, should read this article first. There is, however, a couple of other good reasons not to try it.
>>> Every one of Icom�s various radios has 8 volts imposed on the microphone hot lead through a 100-ohm resistor. In addition, one of the pins has a direct connection to the 8-volt regulator. Shorting either of these to ground will result in failure of the 8-volt regulator--a very expensive fix!
Alan;
Your last sentence in the above exerpt is a good warning; naturally, you don't want to short any internal supply voltages to ground.
Instead of making the Amplified Microphone Project into a scary movie, why not provide the warnings but also suggest some pre-amp circuits that can be tailored for the response of the particular mic element along with some suggested construction details?
i.e. Shure, Heil, cheapie electret condenser types- and yes, even a D104. Contrary to the High End Heil crowd, it is not a bad sounding mic when set up properly. (like most things)
There is nothing "mystical" about adding a preamplified microphone to this rig - including a D104.
I have used a D104 with my IC-740 for over 21 years which uses an almost identical wiring scheme, including the same 8 volt bus (via 100 ohms or some similar value for current limiting purposes) and have received excellent audio reports from all over the world.
(The output lead is also the collector pull up ia the 8 volt bus for a single transistor output buffer.)
The challenges with using a stock D104 is mounting the preamp in the base and of course, wiring it correctly - which is where your warning comes into play - and making sure the preamp is constructed properly, i.e. good board layout techniques, and use of ferrite beads and bypassing to stop RF feedback.
Take a look at the pre-amp circuit Icom uses in the IC-740's hand mic and desk mike. This circuit will work surprisingly well with many rigs, including the Icom 706 series. It can be "tweaked" for different microphone elements or another similar circuit can be used.
Just like other circuits - like the amplifier keying circuit, you need to use care. If you reverse connect the 12 volt supply leads to this radio, the reverse protection diode goes up in smoke and might damage other nearby wiring and components from the heat.
If you know how to read a schematic and plan carefully, this project can be fun and very rewarding, especially when you hear nice clean audio coming through the station monitor.
Going by some posts I've read over the years on eHam, I'd be more concerned about new hams attempting to build their first 20 ampere linear power supply project to run the 706.
I would NEVER discourage someone from building one, but there is a certain amount of planning required -including a known good design, knowledge of good construction practices and the ability to use some basic test equipment to insure the project works before connecting it to the rig, such as full load and ripple tests.
The same approach can be used for this mic project.....
73, Chris
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RE: Rig Woes
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by WA6BFH on June 12, 2005
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Chris, however well executed, don't you find something flipp'n hilarious about putting a D-104 on an IC-706?
The microphone is probably heavier than the radio!
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RE: Woes Me
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by WA1RNE on June 12, 2005
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John;
Yes, the 706 and most other rigs today use a 600 ohm input Z.
The pre-amp is actually being used as a current buffer or impedaaance transformer with some gain, taking the D104's hi-Z, low current output and feeding it to a JFET, then a bipolar transistor buffer that can easily drive the 600 ohms.
Some folks have used just a single JFET which can be done but depends on the JFET selected and may not provide the required gain and can be a bit limited when trying to set up a feedback loop with a specific response characteristic.
73, Chris
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RE: Rig Woes
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by WA1RNE on June 12, 2005
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John, not at all. It does the job well and in my opinion is worthy of being used with ANY rig.
It sounds good to me and most everyone I talk to, it sits on the desk at the right height for most people, the grip-to-talk stand is comfortable to use and locks if needed and it adds the look of a professional looking piece of communications gear.
Like a lot of things, the real "problem" is mis-information and mis-application.
Chris
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RE: Rig Woes
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by WA6BFH on June 12, 2005
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Oh sh!t dude! You're doing this?
Ok, no big deal.
Yes, absolutely -- a fine microphone for the application!
hehe, John
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Rig Woes
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by NG1I on June 13, 2005
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Well that makes up my mind......no ICOM and I'll stick with Kenwood, the TS-2000 when the time shortly comes.
However, Kenwood's TM-G707 dual band mobile comes with that stupid RJ plug which I hate but you can buy a Kenwood adapator so you can attach a Kenwood desk mike on to it for inside home use.
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Rig Woes
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by KG8JF on June 13, 2005
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I have two comments abot this post: I tried to assemble a LAN cable with a crimper and parts. I gave up. The job was impossible. I was unable to hold the eight wires in place while I tried to make the actual crimp.
It appears as though ICOM are doing all they can to make aftermarket accessories unuseable in their gear. I tend to buy Yaesu HF gear and I own two ICOM HT's which I am happy with
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RE: In fairness...
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by K1CJS on June 13, 2005
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"The 8P8C (often called an RJ-45) connector is capable of being put on PC boards via automated processes. It is smaller than the round 'Foster' type connector, yes, and less costly as a component also. But the primary reason it's used is the ability to be assembled by automated equipment. This translates to a higher quality product and lower cost to the customer."
The 'Foster' type connector is also capable of being installed by automated equipment, it simply required a small PC board mounted at a right angle to the main board with the connections between the two boards machine soldered as well.
The RJ connector doesn't require this. Cheaper connector + fewer parts and boards = less cost. In the end, it all comes down to how much can be saved in the manufacture of the rig.
Most hams are cheap, demand cheaper rigs, and are getting what they want. Why do you think some of us are looking for quality? Why are some of us turning our backs on the big three? Why are we turning to other manufacturers even though the cost is more?
Some of us are just sick and tired of being nickled and dimed to death!
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Rig Woes
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by WA4PTZ on June 13, 2005
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Geez.....this and many more horrors of reality are
why so many older hams try to learn as much as they
can about electronics so that they can make informed
and intelligent decisions. Also, so we can make
strange and unusual items work on our radios if we
want and hopefully not make mistakes based on the
misinformation of others who may be less informed
or downright wrong.
I have discovered in my many years that if I ask a
question and I get the same of a similar answer from
several folks that I know or trust then I will use
that information, else....I do my own resaerch.
This is a learning hobby...if you don't want to learn,
find another hobby, or...don't whine when you take
bad advise.
73 - Tim
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RE: In fairness...
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by AD5X on June 13, 2005
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The 8P8C/RJ-45 connector is used by others as well as by ICOM. Look at the TS-480, FT-857D and the FT-817 as other examples.
The excellant point made by this article is to make sure you know what you are doing when you start connecting things to the accessory or mic jacks. I almost always put fuses in-line with any places that I think shorting a contact can cause problems, just to be sure. I buy lots of 1/4 and 1/2 amp pico-fuses for my homebrew projects (and I HAVE blown them occasionally!).
Phil - AD5X
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Woes Me
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by WA6BFH on June 13, 2005
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Yea ya know I think I figured out where I have gone wrong with these RJ type connectors, I have been trying to solder them all these years!
Seriously, some folks were commenting about how they are difficult to avoid “on most of the mobiles now available”. Of these “mobiles” were a number of ‘4 digit’ model radios from the usual suspects, uh I mean manufacturers.
In classes and on nets for many years now I have told new Ham’s and prospective Ham’s to stay away from FM only radios. Not to say that radios such as the IC-706, and the FT-100D etc use these connectors too but, at least they are capable of SSB!
Another interesting thing that has happened about this “stay away from FM only radios” -- in several instances neophytes have come back with an additional question, “are hand-held radios Ok”?
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Rig Woes
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by N8ZT on June 13, 2005
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I've found an easy way to work with the so-called "RJ45" connectors and avoid the problems discussed so far, and take advantage of their cheap cost.
First, start at the RJ45 connector, NOT by wiring the device. Either crimp it on yourself, including all 8 wires, or buy a pre-made Ethernet patch cable (CAT5 or better). Don't sweat which wire goes to what pin yet! If using a premade patch cable, go ahead and cut it in half or at whatever length you need.
Next, get an RJ45 to screw terminals surface mount jack, such as item # 111-300149 from telephoneparts.com ($3.50). Trace the wires inside that jack to the screw terminals, and label them on the jack's face and each screw as 1-8. This is a VERY handy little test rig now!
Plug your cable in process into the test rig. Using a VOM or other continuity tester, determine which pin in your cable corresponds to each wire. WRITE THIS DOWN as it can be easy to mix it up during your project. Make sure no pins are shorted in your new cable! If they are, cut off the RJ45 and start over. If you have a factory mic, plug it in, and confirm (or discover) how it behaves against any schematics you might have.
For the wires in your cable that you won't be using, cut them to around 0.5 or 1 inch and fold them over the main cable, one at a time, taping over each one with electrical tape spaced half over the single wire and half directly on the CAT5 outer jacket. This isolates "stray" wires, and ties them off so they don't short things like that 8 volt regulator and fry it. That is also why we kept all 8 wires in the RJ45; in my experience a full one of those is much less likely to have anything slip than one in which you try and connect only a few pins!
Now you should only have the wires you actually plan to use remaining. Connect these to your device (APRS controller, mic, TNC, computer interface, whatever the case may be!) and then RE-TEST on your test rig to confirm that: No pins are shorted, PTT is where it should be, and the resistance across your mic and mic ground makes sense. Make sure you check V+ against ALL the other pins with PTT open and closed (And any other switches or buttons). Once you have tested it clean this way, it should be safe to plug your device into radio.
Using this method I've made many adopters for my Kenwood 2M, and I also worked with my friend Bob, KC8UIQ, to adapt a surplus Navy Talker's chest mic into a hands free mic for his '706, and he loves it, both for the cost savings verses other options, his affinity for that particular mic, and also for the sense of accomplishment of having "done it ourselves".
I have converted my station at home to use RJ45 switchboxes, specifically two part # 105 0060 from Cyberguys.com ($11.96 each) to select my mic and rig quickly and easily. I have built an adapter cable for an Icom desk mic and have plugged in my Kenwood DTMF hand mic and a Rigblaster nomic to the first switch. I run a standard Ethernet patch cable to the second box (I/O to I/O jacks), and then I have my home Kenwood, Icom, and Alinco rigs plugged in. The wiring is all done on the Kenwood standard (it and the Rigblaster are the only devices natively using RJ45s), and the other rigs have a cable I made using the techniques above to have an RJ45 on one end and a 8 pin Foster on the other. When I find the time I plan to build an adapter box to convert one of three possible headsets to home station use, and the other for use with one of my Icom 2M mobiles for special events. Using RJ45 connectors doesn’t have to be hard, and in fact I often find them quicker, easier, and cheaper than the other types of connectors!
Hope it helps some other people out there!
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Rig Woes
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by KE4DRN on June 13, 2005
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Hi,
Yes, good article.
If more of us would take the time to read the manuals and the schematics like the author, no high dollar repairs would be required.
I disagree on the other comment on 'dumb down'. I guess AT&T dumbed down the standards so anyone can interface telco equipment ?
Even experts make mistakes, Hubble telescope mirror subcontractors, etc.
The D104 is a nice mic.
73 james
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RE: Rig Woes
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by AE4X on June 13, 2005
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"Chris, however well executed, don't you find something flipp'n hilarious about putting a D-104 on an IC-706?
The microphone is probably heavier than the radio!"
My thoughts exactly! I never understood why some want to merge old outdated technology with hi-tech radios. Just a silly practice!
I saw someone a while back asking the same thing but with an IC 756proII. Now why would you ever want to mate a D-104 with such a radio!?!
It's like getting GPS fitted in a Chevy Cheyenne. (an "in-reverse" analogy). It just doesn't go!
Anyway...never liked the D-104. Like talking into a lamp and looks like one too.
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RE: Rig Woes
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by WA1RNE on June 13, 2005
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Yup, that's right.....if one guy decides to twist a couple of wires together without planning out the project first, blame the mic......
.....and while your at it, tell thousands of other hams they made the wrong choice - for the same reason you did.
Kind of silly in that context, huh?
If the D104 is so bad, why did the author of this article make specific reference to it??
Seems to be an "ugly" but still very popular choice....
WA!RNE
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RE: Rig Woes
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by AA4PB on June 13, 2005
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I suppose it depends on which model of the 706 you are talking about. Perhaps design changes have even been made for newer production runs of the same model. My maintenance manual for the IC706MkIIg shows that the only components between the DC input power connector and pin-3 of the tuner connector is a set of relay contacts and a 4A fuse. The switch transistor controls the relay coil. With this circuit I can't see why there would be a 1V to 2V drop unless some in-line connector has a high resistance contact. At 4A it would take 0.5 ohm of resistance to cause a 2V drop. This is the same power source that supplies all of the radio except for the finals. If the voltage is low at the tuner connector then it must be low throughout the radio.
Given the circuit shown in the maintenance manual, I don't see how shorting that particular output to ground would do anything other than blow the 4A fuse which would cause loss of power to everthing except the finals.
Since Alan has experienced these problems I'm quite sure they exist. It would be interesting to know what the circuit differences are and when the occurred. I wonder if Icom made any other changes to protect the 8V regulator - not something I really want to test with my radio :-)
External interfaces are something really difficult to completely protect. You never know when someone is going to short an output to ground or a ground pin to +12V battery. I notice that both Icom and SGC have started including series resistors in the output lines of some of their newer devices - presumably because they have experienced damage from such problems.
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RE: Rig Woes
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by VE7ALQ on June 13, 2005
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I mate a Vibroplex Original "Gold" Bug to my Icom IC-706mkiiG, and use this combo as my base station. Works great, even though the Vibroplex weighs as much as the IC-706. Use optional filters for 500 Hz and 250 Hz.
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RE: In fairness...
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by KG2V on June 14, 2005
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Heh - I want lemo connectors on everything - there is a connector... (Yes, the metal ones please)
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Rig Woes ( a challenge to inventors)
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by K3BM on June 14, 2005
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I very rarely post to here, but the comments on
the RJ-45 connector really hit close to home.
I would challenge you inventor/innovator types,
to create a snap-in RJ/45 to 8 pin converter.
It could be wired for any ICOM / Yaesu or any
rig using an RJ-45 for the mic. Then you would
have built in strain relief and wouldnt have to
worry about the wiring problems.
Please dont flame me if such an animal exists,
but please tell me where I could get a few.
73, Bob K3BM
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RE: Rig Woes
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by WB2WIK on June 14, 2005
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>E: Rig Woes Reply
by AA4PB on June 13, 2005 Mail this to a friend!
External interfaces are something really difficult to completely protect. You never know when someone is going to short an output to ground or a ground pin to +12V battery. I notice that both Icom and SGC have started including series resistors in the output lines of some of their newer devices - presumably because they have experienced damage from such problems.<
It's actually a UL rule that any user interface connector providing a source of current must be fused. Not that this is a "law" or anything, but it is good sense and costs almost nothing. I'm surprised the IC-706 doesn't have a fuse between the 8v regulator and the front panel mike jack. Every cheap home PC has the keyboard and mouse lines protected by resettable fuses; you short out the line, the fuse trips. Wait a minute, it resets so you can try it again.
Lack of such a feature might imply the manufacturer likes having stuff returned for repair so they can charge for service...
WB2WIK/6
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RE: Rig Woes
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by AA4PB on June 14, 2005
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Once again, looking at the IC-706MkIIg service manual, the 8V regulator is a TA7808. This regulator is "supposed" to have both short circuit and over temperature protection built in. Normally you can short the output of one of these to ground without causing any damage. I don't know why a MkIIg would experience immediate regulator failure by shorting the 8V output line unless Icom got ahold of some bad regulator ICs. I've tested other 78xx series regulators for both short circuit and over temperature and they worked as advertised - no damage. I would not normally consider it poor design practice not to fuse the output side of one of these. Of course the input side is protected with the 4A fuse.
This is of course shorting the 8V line to ground - not connecting it to some other voltage source like 13.8V.
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RE: Woes Me
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by WA6BFH on June 14, 2005
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Chris, I know I said I would leave this alone but, come on now! You know darn well, just as I said before, that people use that microphone because of the way it looks! It can sound like sh!t, and probably does, and they will still say it is the coolest thing since sliced bread!
<Yup, that's right.....if one guy decides to twist a couple of wires together without planning out the project first, blame the mic...... >
Well, if one chose a microphone based upon it’s real performance, there are a number of electret microphones made by Panasonic that sell for about $3.95 each, where you can get any audio response that you want. You could even use the Astatic microphone that the company designed for SSB, not the older D-104 that they designed for “AM” -- both of which don’t hold a candle to the little electrets!
<.....and while your at it, tell thousands of other hams they made the wrong choice - for the same reason you did.
Kind of silly in that context, huh? >
What wrong choice? We are supposed to be “electronics experts” right? That’s what you agree to when you get the license. We are also supposed to be able to deal with the tremendously complex engineering problems posed by -- yikes …… a connector!
<If the D104 is so bad, why did the author of this article make specific reference to it??
Seems to be an "ugly" but still very popular choice.... >
Because he is probably amongst the crowd that thinks to be a real root’n toot’n Ham radio operator, ya gotta use a really cool look’n microphone like the D-104!
Maybe even a Golden Eagle! Oooooh Yeeessssssssssss!!!!!!!!
I think I may have to get some clean shorts!
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RE: Woes Me
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by W6TH on June 14, 2005
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.
Japanese engineers know what electronics is all about and learned electronics from books and Ph'ds. Keep what comes with your radios and nothing more will improve it. These are communication microphones. Might be better to alter the audio system for higher or/and lower response.
The condenser microphone was developed in 1916 by E. C. Wente at Bell Labs. It was improved over the next 10 years and became in 1926 the Western Electric 394-W microphone used to produce the first generation of sound motion pictures.
Great post, but I will never sell my D104, I love the looks of a lollypop.
.:
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D-104 on the 706? Why?
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by W5HTW on June 15, 2005
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For some odd reason, the microphone that came with my 706 still works, and works well. I'm scratching my head trying to figure why I'd want to fix what ain't broke, and put a D-104 on there. I haven't come up with an answer.
But I know this. During the mid to late 60s and the early 70s, most CBers wanted either a "power microphone" or a D-104. Or both, which resulted in the power D-104.
Is this simply a carry-over from that? "Gotta have that D-104 lollipop on the radidio." I'm not being sarcastic here. The fact is, the D-104 has to be modified to work with these new radios. So it isn't even a D-104 anymore, huh? Just looks like one. Kinda like painting your Volkswagon to look like an IROC racer.
I don't work for Icom, so I am not trying to redesign the Icom radio. I'll go with what the designers said - I'll use their microphone.
But less I be called appliance operator, I did go into the radio and modify it to operate a small DC relay, which in turn operates the amplifier. And I do use D-104s on the boat anchors, which fits their era.
I simply don't understand the need to put a 50 year old microphone (we had one on a BC614 speech amplifier into a BC610-E transmitter in 1959) on a state of the art radio in the 21st century. There are much better microphones for the job available at reasonable cost.
Ed
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RE: D-104 on the 706? Why?
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by N6BOA on June 16, 2005
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LOL - ok, um, what mistakes could one of us "products of a dummied-down licensing structure" make with a used Alinco DX-70TH???
Seriously, anyone?
73 de N6BOA
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RE: D-104 on the 706? Why?
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by W2LYS on June 16, 2005
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So what would be a good solution... I'd like to have a boom mike and a footswitch with my 706...
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RE: D-104 on the 706? Why?
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by WA6BFH on June 17, 2005
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LYS, if you don't mind 'just throwing bucks at it', get the Heil microphone of your dreams, and wire her up!
Or, select a few of the Panasonic microphones I suggested, and see which element has the audio response you prefer. You can get the boom hardware, and an old mic. housing at a variety of electronics stores, or swapmeets
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Rig Woes
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by KA1CSU on June 17, 2005
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I have the IC-706MKIIG, FT-90R and FT-817 among other gear. They all use modular connectors. As someone pointed out above, there are Kenwoods with modular connectors too (at least one and we are sure to see more, especially in smaller protable radios).
I have had 2 modular connector failures. Both were retaining clips that broke off (one I continued to use for several months with a ruberband holding it in place). Both because I was careless and both were after years of use not that it was a factor. One was due to improper storage with small wires that got under the locking tab and pulled it off when I tugged on the wires - again, poor storage choice. The other a similar end but due to carless storage on day with some other components in the glove compartment and an agressive tug when I knew better.
I repaired one - it took some effort to get the wires in place on the cord for the FT-90R so I could crimp it, but I did get it fixed using a mounted magnifying glass to help with the process. It took some effort and patience getting the wires in place. The MOST difficult part for me was confirming that the wires were in the correct slots before the crimp - my eyes are not so young. Works fine now. I have yet to bother with the Icom mic because I use the Heil headset. Now that I think of it, I will do it when I get done with this post just so I have a backup if needed.
As to the use of a power mic (if I am correct in my understanding of some comments): I have always had great signal reports on my 706mkIIg. I started using the stock mic and switched to the Heil 706 headset for the convenience of a headset/mic and the ability to cut of audio to the external speaker (by using a plug in the ext spr in back) so the XYL can sleep or listen to the radio while I 'play' radio on long trips.
Given the adjustments available in the radio and the microphones I have used, I don't see the need for another microphone - maybe if I wanted/needed a desk mic for home or portable use I would see it different? I have worked world wide with the original mic and the headset and had no problems. Nothing but excellent signal and audio reports. One Russian opp (I think he was Russian) essentially called me a liar for saying I was mobile - I was stunned - so much so that I didn't even think to honk the horn, roll down the window or turn the fan up to generate some evidence for him!
Maybe I just a loud moth with a voice that just naturally sounds so great on the air! LOL - the more I think of it, now ROTFL.
I, for one cannot wait for the IC-7000. Saw it at Daton. Looks like a great rig with improvements on the current 706 model. Kenwood has a couple HF rigs I am considering (and the 2000 is a nice thought too!). I Also like the looks of the FT-897 and could consider something on the order of an FT-857. However, I really like the Icom and look forward to playing with the IC-7000.
By the way, I heard from a reliable source at Icom in Daton that the recent price increase of the 706 is specifically due to changes in cost and exchange rates, not any of the other reasons that I have seen suggested from time to time in various sources since the increase
Anyway, Thanks for a great article and some excellent response.
To anyone who missed the key point as I see it: Know your equipment strengths, limitations and weaknesses. AND know your own! There isn't a lot of 'perfect' out there (really, none from my perspective - not even the great new rigs in the 10k+ range, although they are obviously great radios with some excellent features). It is not Icom that is a 'problem.' There is clearly enough information presented above to demonstrate issues with all manufacturers. All radios have issues - the world is not a perfect place and most cannot agree on what perfect is or would be. This is generally because people have different needs, prefernces, skill levels (technical and otherwise), etc.
Again, thanks for an excellint article and some excellent feedback, as usuall. I learned a lot about various 45 type connectors and more. I was also reminded to check the specs and design before attempting to use non standard equipment or modifications. Maybe that is part of the reason I have had good luck with my radios... except for the occasional out-to-lunch error as with the FT-817.
(an accidental powersupply short to my unfused counterpoise while foolishly moving the radio in a protable setup while plugged in and powered up - I was sure I had the battery terminals covered but the counerpoise found a way - my failures - not Yaesu/Icom/Kenwood - they con only make them just so idiot proof - I am not an idiot, but I did an idiotic thing!)
... I generally do check carefully before I start playing with things. However, a reminder and specific details as pointed out above are always welcome. I would have prevented the minor damage to my 817 had I fused it like I knew I should and/or had I used common sense while movin the setup.
73, Paul
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RE: Rig Woes
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by KC9AGG on June 20, 2005
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speaking of connectors, how does one wire a 13 pin din plug ? on instruments in the lab, most manufacturers use little pins which slip over the contacts to allow a wire to be soldered or crimped...what am i missing for this one? good article, thanks.
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