Icom IC-7100 mod low SSB power

| abril 8, 2016

Icom IC-7100 Modification Low power output on SSB

The issue with the low output of the IC-7100 busied myself now already more than two years long.

In the summer of 2014 I am, more or less, encountered by chance on the problem with the transmitter power. In mobile operation with two identical cars, with the same antenna and tuner, got my IC-7100 always by about two to three S points poorer reports as an IC-7000 in the other vehicle.

The phenomenon has repeatedly and over a longer period of time, whether mobile or stand while driving examined. Then more radios were tested a Yaesu FT-897 among others. It always gave the same result, the IC-7100 was run with every two steps worse, no matter what was used as a reference device. Comparative measurements of the output power with the other devices showed that the average output power (AVG) was always too low in IC 7100 with language.

The display shuttled around in slippers 20 watts, while the display is always at about 40 in the others – was 60 watts or higher. I want here no debate about PEP or the power meters used trigger, it is here one and only is a “comparative measurement” . It is also totally indifferent to which instrument I measure. Ultimately, always the one that “what comes back out.” Incidentally, in steady state operation with dipole antennas with signals of S 9 or above noticed the problem with little or no.

In mobile operation, however, the relatively inefficient antennas, it depends on each watt. There is a huge difference whether you will be heard as a mobile station with S3 or S5. The subject occupied me now over a longer period. There was on the device is still under warranty, it was in 2015 sent to the ICOM-Service, from where it is returned unopened with the same symptoms after 3 weeks. The Declaration of ICOM on the problem I want to spare me here.

The internet was now en masse complaints from around the world on this subject. Unfortunately, no one had to offer a reasonable solution, except a few smart sayings on the measuring methods. (See note above)

When visiting the HAM-Radio in 2015 was flatly denied by the present German and Japanese engineers the problem. Only after persistent prodding, and the presenting of the already made ​​correspondence, it had admitted that the problem is yet known. In Japan, one would also have been working on a solution. As this solution is then, however, looks, if there is a hardware or software solution and when, if they appear at all, that was not to elicit the ICOM people.

I followed thereafter its own way. Agent compared with several transceivers from various manufacturers cut the IC-7100 case from getting rotten. In language the wattmeter when IC 7100 max showed. 20-25 W, while the other devices are always in the tips of the 60 – 80 watts. All settings in the menu as well as various other microphones brought no improvement.

Then I took the service menu settings even more closely. It has the IC-7100 unfortunately little or no adjustment, since the service balance largely automatic. The analog time of trimming potentiometer is now over. Only the supplied audio input level can be changed.

After days of testing, with infinitely long series of experiments on the matching software, then I’m obviously come behind the secret. You have extremely far lower to the ALC to outsmart the automatic adjustment for matching the AF level. This is feasible only with a precise AF level transmitter. Even the slightest changes in the output level of 0.5 dB are included in the balance. So I managed the average output power of the IC 7100 to increase to about 80 watts.

Subsequent verification with a spectrum analyzer or a SDR radio showed no abnormalities in the signal. By the way, all the cleverness Meier who say could with another microphone to improve something – that are completely wrong, which brings nothing! ! ! Now that I have received several IC-7100 from other hams in the hand, I realized that the VHF range was adjusted sloppy on some devices. A device produced only a mere 5 watts in SSB. After readjustment whopping 50 watts could be measured in the speech peaks. The UHF range was strangely okay.

I just wonder how such poorly matched devices can ever leave the production. Where is actually the quality assurance? Presumably the customer. In the coming months, the IC-7100 has been tested extensively in mobile operation. With the result – it was as different as day and night. At 40 m were all belonged stations also work with 1KW, which was not possible before.

The end of 2015, I learned from a hardware modification, which published Marios SVØCL, chief engineer of ICOM, in Athens. Curious, I of course immediately tested. The result was stunning. Now the IC-7100 makes a spurt. In the speech peaks the watt meter shows loosely at 100 watts. Even after this conversion no undesirable by-products were observed.

My reports are now almost always at S 9 Now makes the IC-7100 real joy.

Meanwhile, I have modified several IC-7100 with great success. The owners are all very pleased with the performance.

Now for modification: You can find this on the Internet on YouTube some videos, but they are written in English or Polish and the picture quality is relatively poor.   Therefore, I have the whole issue of transmission power   of the IC-7100 worked for the German OM again and here released. Before you begin, you should also be absolutely clear about whether the modification also trust yourself. Good eye, a steady hand, a good soldering iron and a strong magnifying glass is essential.

Two modifications are possible. The first is almost double the average power with SSB.
A bridge from point (A) to ground.

The Second for “full power” required in addition to the jumper  a 10 uF / 16 V electrolytic capacitor (or tantalum), this is in parallel to R1522.

Icom IC-7100 Modification Low power output on SSB Icom IC-7100 Modification Low power output on SSB Icom IC-7100 Modification Low power output on SSB

Open the device by removers the bottom of the housing. Place the device on the table so that you can see the two connectors as in the photo in front of him.

The jumper is still relatively easy to install. However, the soldering of the 10 uF Elko is a challenge. The SMD resistor, through which the Elko is soldered is only slightly 1 x 2 mm in size! The soldering is very difficult and there is a great risk of a short circuit. Therefore, I have a better solution for soldering the capacitors.

In the pictures show how to the Elko solder safely. I have also been used tantalum capacitors with success. When mounting attention to the polarity. The solder joints are then always to check with a good magnifying glass and, if necessary, is excess tin to remove. The Elko should be a precaution fixed with some tape or a drop of superglue.

Icom IC-7100 Modification Low power output on SSB Icom IC-7100 Modification Low power output on SSB

For the conversion, I reject as usual any responsibility for any resulting damage. Allen, who are confident the modification, I wish a lot of success and fun with a ” new IC-7100 “. My special thanks go to Marios SVØCL, Thilo DL9NBJ, Lothar DL9NBD for their support in the many tests and Achim DC4NV for more information and proofreading.

Finally, you will find the measured values ​​before and after modification in two impressive Files

Both videos were recorded with the same text and with the same level. Sound is not played back.

Original:  Geringe Ausgangsleistung des IC-7100 bei SSB.

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