Excellent job Peter. Always fun trying to fit through hole components on a SMD board. They really did goof on this radios ALC circuit. Glad you came up with a fix for it. Mike
+MikesRadioRepair Hi Mike, yes through hole and smd is always fun :-). But in this situation no smd part would fit that's the problem.. Yeah fix works great. Thanks for stopping by 73
I just performed this mod on my icom 7100. It works quite well and the signal quality reports were good in the qso after I finished the changes. I was aware of this before, but I was hesitant to do it until I saw that this individual, who's technical skills I respect, showed that he had implemented it and, importantly, showed the justification for why it works. This gentleman posts superb videos. Anyone who gives him a thumbs down is just bent.
Nice video. I used to have this problem. Just checked it on my peak ready watt meter and I am getting an easy 100 watts with 52 percent MIC gain. Seems the E5 firmware fixed it for me. Glad I don't have to solder! Thanks for the interesting video
I made the 2 modifications and are now happy to have a really clear and undistorted SSB-modulation that really draws the attention on shortwave even if I hold the mike (HM-198) 40 cm from my mouth. and it can easily be calmed down by shutting off the compressor/reducing the mike-gain. Thank You again TRXBench!
@@tomch4467 The stock mic is not the best, I rearranged the wires if HM-219 to match the ic-7100 pins, radio works at 100 watts. Check your SWR to get full power, icom recommends 1.5:1. Have fun.
Hi Peter, greetings from Puerto Rico. Purchased my IC-7100 back on Dec 2016, the firmware update did not fix the RF out issue in HF SSB, I had been watching you videos, very informative & educative. Excelent video. Because of the low power in HF SSB I decided to perform very carefully the modification in my IC-7100 and the radio is working fine. Thank you for spreading the modification procedure ! 73's Tony-KP4IA
Hello Peter, One tech to another, Your modification does work indeed, overly so. 2uf to 3uf is far to much capacitance on that ALC voltage rail. What all of these videos do not comment on is that you loose total control of the power level control. As soon as you adjust power output past 15-20 watts setting the radio is hammering 120-130 watts in that essentially there is little to no ALC action with that much capacitance. Not to mention a monster axial cap is ugly against that beautiful SMT board. Next time you make this mod might I suggest using a .1uf (yes, point one (.1uf) ceramic 0805 cap tied in the same fashion from that ALC rail to ground. You will see the same ALC improvement, retain same linear control of the power output control function. And, yes your right, do not add that short wire....just the .1uf ceramic non polarized cap. Nice and clean.
Hi, do you realy think or tested that a 0.1µF capacitor over the R1522 is enough? I understand you tell no bridge over transistor Q1504, isn´t it? I did bridge it and I can not reduce power any more for example 10W without big peaks. That´s not good because my LD-MOS PA needs only 20W for full power output. Overshot is forbidden. 73 de Frank, DL2GRF
WOW, A you tube video I actually enjoyed ! Reminds me so much of when the guys from Europe would come over and do training with us on the Xray units. Thanks for the video, and your time !
I called Icom repair in Michigan and spoke to them about what Icom told them to do if anyone complains about low audio on the IC-7100. I was told to upgrade the firmware. I am happy to say that once I did the last three upgrades, my SSB audio was corrected to read near 100 watts on Hello, Audio, Hello Audio. No yelling involved, and MIC set at 65%. Comp on yielded the highest reading, Comp off was slightly less.
While I would not doubt the success of this mod, I would, however, be wary of overstressing *other* components. A few years ago, people were modding Kenwood TS-50s and bragging about 150 watts output. Then *POP*!! There went the finals! I would err on the side of caution...and take YOUR approach!:)
Nice modification. I would feel a little nervous though that the radio was now putting out too much power. But as usual thanks for making the video really interesting.
Hello Peter, the wright questions have been asked and answerd about modulation and IMD and if the PA is happy we are happy. Very nice mod, good explanation. I think you saved a lot of radio's for selling. Take care until next time. Henk
Peter. Just wanted to say thank you for all your videos. I find them very interesting and informative. And really appreciate you speaking English to include the wider audience like me. 73 Jon G4VFT
+The Radio Shop Thank you Buddy, well may be components tolerances which has not been calculated in developing.. LOL yeah looks like fly shit...:-) Take care friend
Great modification Peter! I don't own 7100, but I was really surprised as to how come ICOM itself missed this obvious ALC problem before market release. That's one reason, I never ever buy new models until they have been extensively tried by ham operators. 73, Kostas.
Pete I bought my 7100 a few months ago and it has the latest firmware in it from the factory, it's all up to date and the only way I can get up to 100 watts is to use the compressor, so after your mod the jumper and the cap I got full power plus some extra. With the compressor off I turn it down to 100 watts peak and it plays fine, it also drives my als 500 better without sounding over modulated, thanks for the mod and I love your videos, 73 kc8hxr/6
Fantastic Video Peter ... Many Thanks ... One question ... I presume the little Fly SH.T resistor was removed and that you bridged the 2 points with the lead of the Capacitor ... Mike M0csi ...
Maybe we are so lucky that this modification made the modulation really clean and "unstrangeled" that the ALC now works as it should and that the "SSB-drive" in the setup menu have to be set lower because the factory setting had to be set way to high to compensate for the flaw in the ALC-design. (of course it was factory-adjusted with a pure tone fed to the mic-line and not a voice.. and therefore whistling in the microphone always gives 100w+ power output, and therefore Icom did not detect the flaw as they use a tone)
+Lars Johansson Hi Lars, all tests before we released this were positive. We tested different cap values and found 10uF to be good. Mod is clean even with compressor. 73
Another excellent mod/repair. It amazes me that Icom (or any high tech company) would allow equipment to be built with an inherent problem like this. People pay hard earned money to own a piece of equipment that should work for years without an issue. Especially an issue that doesn't have to due with age and or, wear and tear from everyday use. More testing before release of equipment would solve unnecessary failure. Manufacturer should catch poor design before the item is released for sale. Excellently produced video as always.
Did the mod to my 7100, had VE6JF do the work for me (Briillant Guy), went from 17w peak to 97w. Thanks for the detailed video - could not have done it otherwise. !! (VA6QAS)
hi Peter,i know this video is old but i find it very helpful, i got a new icom 7300 that had the same issue right out of the box,i did the mod on it and i am very pleased with the end results,it was doing no more than 60 watts on ssb mode and now it does about 135 to 140 watts after the modification,i used a 4.7 microfarads 16v capacitor, will it work better if i had used a 10 microfarads capacitor as you used on the icom 7100? thanks for the great and useful videos Peter 73
So we have to consider that the Icom engineers knew about this, and they reduced the output power to correct a separate issue. If that was the case, the real issue might be that the increased power causes some other failure that Icom would be responsible for fixing on their dime. Only time will tell. So if somone makes this mod, and they give the radio a good SSB workout, if that causes a failure in some other related circuit, it would benefit all IC7100 owners to hear about it. I am not a heavy SSB user, and my main radio for SSB is the IC7600, my IC7100 was left for Dstar use only. Although, I have to say that Dstar on HF has been less than good on the IC7100, where SSB on HF using the IC7600 has been great on the same antenna. This MOD seams easy enough to make, but you have to wonder how it got past quality control at Icom. The only honest mistake could be if the original IC7100 had other parts, and at some point the quality of those parts had changed. The only way we could know that is if we hear from some of the first IC7100 owners and see if they had this same problem. The IC7100 has been out for a while, so a change in parts could be the cause of this RF problem. This is my opinion, so please don't flame me for it. Joe KQ4BX
+Joseph Massimino Other persons opinions are always welcome! I don't think that 7100 is having a weak Power stage that could burn if transmitting with normal levels on SSB. Maximum power output on other modes are really good on my 7100 and I can transmit for extended periods of time without detecting any unnormal sweating. I guess that Icom in some stage when designing the rig did not really consider the importance of finally testing the rig in real use before pushing the start button in the factory line. And the reason for this ALC-flaw can be as You said component(s) changing quality.. I am a real novice but as You I also try to understand how Icom could release a rig with this kind of serious flaw. When remembering the IC-2820 and it's low quality modulation that went really bad when Icom suddenly decided to ship the rig with the cheap China manufactured microphone, it looks like Icom don't care much about testing anything at all when changing the original setup.
In my past experience i have increase the power in 4 radios to 200 watts ///kenwwod ts-50 // ts-930 and ts -940 ,,, and ft 1000...and never have any problem with them until i sold them...but i was heavy criticize for doing this,and almost all of this guys says that i will fry my radio in no time...that never happens...i am glad that he post this video,if i ever purchase this radio i will do this modification for sure,i take the risk...i need those 100 watts baldly no Mather what...but i also agree with your comment ,is very true,i respect your point of view//////,after this mod is performed only time will tell...73
Thanks a lot for this great video (Again!!), did you try same workaround on ic746 (non pro)? I found the power in SSB to be 40 to 60 Watts while 110 in RTTY. I located IC971b on POCV line but I'm unsure how to adapt your work. rgds, 73's G
Hi Jerry, Great video. Very low average and peak power was the first thing I noticed when my new 7100 arrived. My solution was an amp but now I want to install in my truck. There is another RUclips video where the guy just did the jumper and not the capacitor. I thought your video said the jumper was for AM but his power went up on all bands SSB and the power delivery seemed more aggressive than your mod. What are your thoughts about just a jumper? Also, I am having trouble locating a radio shop to complete the mod. Do you know of any in the states? Thanks again for your videos. I am learning much. Brad
Hi David, I made the modification but after that the Radio no power output in HF, I have reversed the changes and same no power 0 Watts. Please let your recommendation to make a trouble shoot. TY
Nice Mod to the ALC, The only thing I would do is add some RTV to secure the cap to the board as this is a portable radio and is subject to some harsh handling and can cause the solder joints to break lose or the pad to come off the PCBThanks Keith N9QDS
I hope you put a dab of silicone rubber or equivalent on the capacitor where it meets the board or road travel movement from bumps will cause it to fail
hi, i am experienced electrical/electronic engineer, have the ic7100, would like to know is there any possible/expected damages in few years later after this modification done? and whats the different from your point of view if using 50uF or 100uF instead of 10uF capacitor? 73 de 9w8haz
You are a genius! I've watched several of your videos and have subscribed even though I'm not likely to ever try by myself. Im brand new to HAM radio and found this video by chance since I just ordered an ICOM 7100 like an hour ago. I don't have an LP-100A...how will I know if my 7100 is suffering from this problem?
I know this is an old thread/video, I did the mod on my 7100, have a slight issue, wonder if anyone else has this.. I have the Icom AT180 and a diamond mobile antenna, with the mod'ed radio, when I key (very noticeable when I use the SWR test) the power and tune bounces very rapidly on the bar graph. when I use it to talk the tuner will cut in and out and then the tuner goes out of line alc exceeds the limit and then cuts power. remove the capacitor and all back to normal.. is this a bad capacitor, or rf getting back into radio. mod removed at moment, any thoughts? thanks
Hello Peter, thank you for this video that I have just discovered. If I understood the fault comes from the circuit which limits the power when the SWR is high. Do you confirm that after this modification the power circuit is no longer protected? Indeed I am going to use an IC-7100 with an AH-4 and I am afraid at the beginning of the tuning of the tuning box the ROS being high this destroys my RIG. What do you think of that?
I wonder if this modification does have any effect on ALC function also in DV and FM- mode? I hope it does because I hear many IC-7100's having issues like unclear blurry distorted characteristic sound when I listen to other ham operators.. It sounds like over aggressive limiting of the modulation level that adds "artifacts" to the modulation. So, could it be that this is the same reason why it limited the SSB-output so hard and that both problems will be taken care of when adding this modification? Or maybe just maybe this modification only affects the SSB and that Icom have made a similar error elsewhere in the design? (I imagine that the reason why Icom did not detect this error are because a signal tone-generator and not a real wider voice-like signal is used when designing and adjusting the level of modulation and setting when the limiter should start to work). The SSB power is ok when whistling, but when a wider signal is input, like a voice it gets limited way to early).
Peter, another great video. Did you check the output with a spectrum analyzer after the mod? Just wondering if you are now over driving the PA?? I probably would have used thin #30 wire to connect the new cap to the SM resistor. I would also glue down the new cap. Maybe you did all this or equivalent but didn't show it? 73's KA2ZOH
+Herbert Susmann Hi Herbert, yes of course, we tested this mod before release extensively. IM3 with compressor is 28-29db and without compressor 31-35db related to the avg single tones of 44dbm in test configuration. If you would like the calculation on PEP simply add 6db to my test figures. Yes cap is fixed with hot glue. Thanks for feed-back 73
+TRXBench I should have figured your usual thoroughness meant that this was already checked out. You never know with this stuff and since it wasn't mentioned in the video I thought I should ask so others might see your answer also. 73s
+Herbert Susmann Hi Herbert, no problem and nothing wrong with asking and rather more I should have mentioned it in the video so it was my fault. Thanks for your comments! All the best Cheers and 73
Well done Peter! Question: Where did you obtain the block diagram, schematic, and PCB layout? I would like a copy myself to review. I have a 7100 on order and I eager to perform this mod. Thanks again!
Hello Peter, nice work ! I have a question, why have you bridged the transistor ? Why not just put the capacitor to hold the voltage and make the alc slower , isn't that enough ? If the transistor is used for AM mode control shouldn't you have left it like it was ? Thanks and 73!
+CT1ELP Hi Pedro, it is important to get the right balance between speed and performance. The mod will work as well if you put in the bridge only but it is not so efficient. If AM is engaged the transistor is switched on that is like a bridge.. so no problem. Hope that helps 73
Hi Peter, A great mod on the ALC line. however, with the pa now producing about 135W + PEP how hard are the PA transistors being driven or maybe over driven? And also, It would have been nice to see the spectral purity of the transmitted signal. Maybe Icom had to limit the power to meet spectral purity specifications? A before and after video of the transmitted signal quality would have been nice to see, especially if the radio is to be used for Data transmissions FT8 RTTY SSTV etc? Last thing any ham wants is poor IMD and a splatter box!
Adding the jumper AND adding the capacitor breaks the AH-4 tuner functionality. The RF comes up slowly when the Tune Button is depressed and the AH-4 times out (rather rapidly). I left the jumper on across the transistor but removed the capacitor.
I'm confused as well. Just speaking into the mic to try and determine SSB performance doesn't work, it requires a 2 tone continuous signal. Plus I can't help but wonder what does the received audio sound like after the mod?
Maybe compliance and alignments at lab to avoid RFI or some spurious emissions. Now with better home technologies, CB-ers get away with high power amps. Some IC-7300 for example has 25 watts in AM while the IC-7100 has 30 watts, some state 40 watts?
@@k2icc That still doesn't answer the question of why a radio manufacturer who markets and sells a transceiver touted to have 100 watts RF output can't do what it's advertised to do without modification. Nearly all 100-watt transceiver put out at least ONE-HUNDRED WATTS (or better), yet this model falls short. Just makes no sense why that is.
@@greenrefrigerator Unless people like you and me bring those things up, no one will listen to it or will care, to be honest. There is a lot going on. In plain words, a certain percent of power at a certain mode, could be considered legally what they state. For example, my internet provider sells me up to 400 Mbps. So, I don't get 400 Mbps, but close to 380, and still legally stated. So, they could state, due to some kind of whatever spurious or this or that, the reason for the values. This guy on the test knows what he is doing, so he can do what most can not do, as the equipment needed to prove the radio has certain amount of power, and that on a new radio can void the warranty, etc.
Hi Peter. Thank you for your video. I did this mod a long time ago after watching your instructions and it really works. This is really a great radio and I'm sure with new versions Icom has incorporated your modification in the latest design. I will check the latest Service Manuals and tell you if I find it. Thank you again. Well done well presented 73! de ZS6PVT
Peter - have you listened to the audio quality after you made the mod to see if there was any indication of distortion or did it remain clean? 73 - Dino KL0S
+Dino Papas Hi Dino, yes you can be assured we have a 100% clean modulation even with compressor on an mic gain on 100%. We have extensively tested it before release. IM3 products are also clean. Thanks for asking and for stopping by! 73
Hello Peter, I'll be doing the 'Fly Sh-t' mod at the radio club tomorrow. Thank you for the info and I'll let you know how we get on. 73 from Colin 2E0KOL.
This Radio is perfect! Here is the respond from Icom about the TX low power. Thank you for contacting Icom America. Icom's position is that the model 7100 is operating according to it's specifications and it's design. The firmware that you mentioned only allows the meter to operate with a faster sampling rate, it does not provide a "cure" or "fix" because (in Icom's opinion) the radio is not broken. We do not support the modification of the radio, and Icom could not do any such modification however, if the operator chooses to have it modified, that would be their choice. We appreciate your understanding.
And that is why I refuse to ever spend my money on a new Icom, I will only buy used and put my money in private hands, I greatly dislike Icom's attitude.
I Bought a IC 7410 and I sometimes wonder if I should have purchased a 7100 . I see or I don't think it has a built in antenna tuner, that is a con I am perfectly happy with my radio I only like the Dstar option and the uhf vhf option. Maybe some day I will purchase a IC-9100 that has it all. I guess I have some deciesions to make. I will really hate to get rid of my 7410 it has been flawless. N3SXW
So does the 7300, mine went up to 127w pep from a previous max of 96w pep and everyone noticed how much richer was the bass in my audio after the ALC mod.
Hello. Mounted 10 microfarads, on the transmission there are bad spitting sound on self-control. Mounted 1 microfarad was excellent ALC. Put 1 microfarad!
I just bought an Icom-7100 because I wanted a new radio for my vehicle. Bought 12-Dec-2021. I also bought the optional HM-151 microphone. Full 100 watts output without compression. This was transmitted into a dummy load. I also sent the microphone to have Bob Naggy modify the element, add an ounce of extra weight to it and he also drilled the hole larger in the mic face and put more of a filter behind it. It now keeps the breathing and spitting sound away. I do not understand why my radio and others transmit the full 100 watts out while others complain. There is an upgrade to the firmware in 2016 but I think it was before this video was uploaded. I understand and have tested the stock HM-198 and find it really is not a good match to the radio. The optional HM-151 is and after the modification to it, it is excellent. Don't modify the radio because it has a poor stock mic!
Wonder what the peaks of the ssb envelope look like... Seems the peaks would be clipped & only limited by the PA's maximum voltage capability without the ALC reducing drive... Are you able to do a follow-up video showing the output on a scope with this modification? A theory I have is that one could 'trick' the ALC threshold by doing a 're-alignment' of the output power calibration procedure on the ic-7100 using 130 watts & scaling it for the lower power calibration points to accomplish similar ends, while also keeping the ALC intact. I guess I'm lucky though, my ic-7100 produces it's rated output, but I agree that the ALC on SSB is finicky w/ certain settings.
+DDSPL15 Hi, we tested this mod before release extensively. IM3 with compressor is 28-29db and without compressor 31-32db related to the avg single tones of 44dbm in test configuration. If you would like to have the calculation on PEP simply add 6db to my test figures. Audio was tested on the air crisp and clean. Thanks for watching 73
+TRXBench At what power output was this conducted at? I wouldn't expect IMD to increase w/ this modification if the output power remains below the maximum voltage swing of the PA; THD can even decrease slightly as you get closer to maximum voltage swing on a Class AB amplifier. However, without ALC limiting, the only thing preventing a clipped output is the maximum voltage swing capability of the PA, unless one manually turns down RF gain to prevent the peaks from trying to exceed maximum voltage swing of the PA.I guess the IC-7100 could also do RF output limiting via Id current sensing, but I'm unsure of this and the peaks of the SSB envelope could be just as clipped depending on how it is implemented in the DSP and/or CPU. The PA output devices in the IC 7100 are rated at 70 watts w/ a 12.5 Vds, they are in complementary Class AB configuration which could "safely" allow for 140 watts PEP output under IDEAL conditions; my guess for the reason why 140 watts was the peak output you measured was likely due to some sort of programmed 'fail safe' hard current limiting of the output devices, thus no more current, no more voltage swing. If this Id current based RF output limiting is being implemented via the DSP by reducing IF output gain in a similar manner to how the ALC functions, then I guess the PA output could still be relatively clean on the peaks so long as the DC power input voltage was sufficient to maintain Vds voltage headroom. All of this is just a guess though, but I'd bet even w/ this mod that you won't see more than 22 amps of Id, which happens to be the maximum spec for the radio & likely programmed to be the limit as well. Did you look at the SSB envelope on a scope w/ audio, or perform any maximum power transient / pulse IMD measurements? I hope I'm not coming off to be negative about your video or your work as I do enjoy your channel; I just want to make sure everyone understands the full picture of what this modification may be doing to their transmitted signal :)
Hello, very good work and explanation, congratulations. I have a question about IC 7100 and this change made is about updating firmeware released by ICOM to resolve this low power, I do not comment your I was curious to know if would have to make its modification along or not the update of ICOM, thanks.
+Carlos F Jr Hi Carlos, you should do the firmware upgrade in any case first and see how it works. Our experience is that the difference is not that huge. After that you can go for the hardware mod. Thanks for watching and feed-back 73
Great video as usual, while I don't own the radio in question it's always informative to see the schematics and learn a little more. Would it have been easier or neater to add a ceramic MLC part instead of the electrolytic I wonder?
I have to respectfully disagree, there are many ceramic 10uF capacitors available, in fact the values go up to 220uF 25V and possibly higher, however I did make a small mistake, I missed off a C, I should have typed MLCC.
Clint, off course you are right where was my brain LOL. And yes it is possible to use those caps. I simply don't have them on stock :^) . So completely my fault sorry. Cheers
@@TRXLab Most definitely not true, they are readily available. A Kemet 10uF ceramic 805 SMD 16V capacitor - RS part number 691-1161 cost 10p each, currently 5000 in stock, 1 day delivery here in the UK - and many other makes also available. But as has been mentioned, 10uF is far too high a value to achieve what is required.
Excellent job Peter. Always fun trying to fit through hole components on a SMD board. They really did goof on this radios ALC circuit. Glad you came up with a fix for it.
Mike
+MikesRadioRepair Hi Mike, yes through hole and smd is always fun :-). But in this situation no smd part would fit that's the problem.. Yeah fix works great. Thanks for stopping by 73
You always do a great job on these videos Peter. Thanks for doing these for us..
I just performed this mod on my icom 7100. It works quite well and the signal quality reports were good in the qso after I finished the changes. I was aware of this before, but I was hesitant to do it until I saw that this individual, who's technical skills I respect, showed that he had implemented it and, importantly, showed the justification for why it works. This gentleman posts superb videos. Anyone who gives him a thumbs down is just bent.
Thanks for the kind words! 73
Nice video. I used to have this problem. Just checked it on my peak ready watt meter and I am getting an easy 100 watts with 52 percent MIC gain. Seems the E5 firmware fixed it for me. Glad I don't have to solder! Thanks for the interesting video
Hi Laurence, thanks for the feed-back. Very good that it worked with the new firmware for you! 73
I made the 2 modifications and are now happy to have a really clear and undistorted SSB-modulation that really draws the attention on shortwave even if I hold the mike (HM-198) 40 cm from my mouth. and it can easily be calmed down by shutting off the compressor/reducing the mike-gain. Thank You again TRXBench!
Hi Lars, I'm glad that the modification turned out that good for you! Thanks for watching 73
ICOM has corrected this issue. The IC-7100 I bought 4 weeks ago has full SSB output. It was one of the first things I tested.
Dave, thank you for posting this. I was considering a purchase and I am happy to hear this has been corrected in manufacturing.
@@andrejstefanovski
I bought one 3 month ago and it's transmitting stated watt.
what a rig I tell ya!
How can you tell if the one I purchased two years ago has been corrected
@@tomch4467 look at your power meter on radio to see if it swing's to 100 watt
@@tomch4467 The stock mic is not the best, I rearranged the wires if HM-219 to match the ic-7100 pins, radio works at 100 watts. Check your SWR to get full power, icom recommends 1.5:1. Have fun.
Hi Peter, greetings from Puerto Rico. Purchased my IC-7100 back on Dec 2016, the firmware update did not fix the RF out issue in HF SSB, I had been watching you videos, very informative & educative. Excelent video. Because of the low power in HF SSB I decided to perform very carefully the modification in my IC-7100 and the radio is working fine. Thank you for spreading the modification procedure ! 73's Tony-KP4IA
Thanks for your feed-back! It is good to have here different results collected as it gives a full picture. So again thank you. All the best and 73
Hello Peter, One tech to another, Your modification does work indeed, overly so. 2uf to 3uf is far to much capacitance on that ALC voltage rail. What all of these videos do not comment on is that you loose total control of the power level control. As soon as you adjust power output past 15-20 watts setting the radio is hammering 120-130 watts in that essentially there is little to no ALC action with that much capacitance. Not to mention a monster axial cap is ugly against that beautiful SMT board. Next time you make this mod might I suggest using a .1uf (yes, point one (.1uf) ceramic 0805 cap tied in the same fashion from that ALC rail to ground. You will see the same ALC improvement, retain same linear control of the power output control function. And, yes your right, do not add that short wire....just the .1uf ceramic non polarized cap. Nice and clean.
Hi, do you realy think or tested that a 0.1µF capacitor over the R1522 is enough? I understand you tell no bridge over transistor Q1504, isn´t it? I did bridge it and I can not reduce power any more for example 10W without big peaks. That´s not good because my LD-MOS PA needs only 20W for full power output. Overshot is forbidden. 73 de Frank, DL2GRF
WOW, A you tube video I actually enjoyed ! Reminds me so much of when the guys from Europe would come over and do training with us on the Xray units. Thanks for the video, and your time !
Thank you. Did you work for an European company??
I called Icom repair in Michigan and spoke to them about what Icom told them to do if anyone complains about low audio on the IC-7100. I was told to upgrade the firmware. I am happy to say that once I did the last three upgrades, my SSB audio was corrected to read near 100 watts on Hello, Audio, Hello Audio. No yelling involved, and MIC set at 65%. Comp on yielded the highest reading, Comp off was slightly less.
Hi Joseph, very good that it works with the new firmware in your case. Upgrade first is what I always recommend . Thanks for comment 73
Okay.
While I would not doubt the success of this mod, I would, however, be wary of overstressing *other* components. A few years ago, people were modding Kenwood TS-50s and bragging about 150 watts output. Then *POP*!! There went the finals! I would err on the side of caution...and take YOUR approach!:)
Didn't work on my radio
Nice modification Peter! Very well done.
+Nicholas Hyer Thank you Nicholas. 73
Thanks Peter. That "fly shit" was funny. It is also accurate. lol Those things are so tiny nowadays.
+Robert Calk Jr. LOL yeah it is also accurate.. Thanks for watching Robert 73
Nice modification. I would feel a little nervous though that the radio was now putting out too much power. But as usual thanks for making the video really interesting.
Hello Peter, the wright questions have been asked and answerd about modulation and IMD and if the PA is happy we are happy. Very nice mod, good explanation. I think you saved a lot of radio's for selling. Take care until next time. Henk
+FEY Hi Henk, thanks for feed-back 73
thank you for this video! I had the same problem, sent it back to the dealer and it was returned modified.
What did they do?
Thanks for the video, I always learn a lot from these.
Glad that you like it, thanks 73
Peter. Just wanted to say thank you for all your videos. I find them very interesting and informative. And really appreciate you speaking English to include the wider audience like me. 73 Jon G4VFT
Hi Jonathan, thanks for the kind words and thanks for watching 73
Nice job on that Peter. They really had that one cranked down.Fly shit, I loved it. Laughed so hard. Take care my friend.
+The Radio Shop Thank you Buddy, well may be components tolerances which has not been calculated in developing.. LOL yeah looks like fly shit...:-) Take care friend
Outstanding as usual Peter.
Great job done, Peter! Happy new year
Thank you Kirk! Happy new year!
Great modification Peter! I don't own 7100, but I was really surprised as to how come ICOM itself missed this obvious ALC problem before market release. That's one reason, I never ever buy new models until they have been extensively tried by ham operators. 73, Kostas.
Hi Kosta, thanks for stopping by. Yes you are right it is always good to wait until a radio has proved that it works.. 73
Pete I bought my 7100 a few months ago and it has the latest firmware in it from the factory, it's all up to date and the only way I can get up to 100 watts is to use the compressor, so after your mod the jumper and the cap I got full power plus some extra. With the compressor off I turn it down to 100 watts peak and it plays fine, it also drives my als 500 better without sounding over modulated, thanks for the mod and I love your videos, 73 kc8hxr/6
Ahh very good glad that the mod was helpful to you and thanks for your report! 73
I passed the url of your video to some of my local radio club members as some have this radio and could be good for them to see the modification.
+BeachSandInspector Technologies Hi, thanks for feed-back and for passing over to your friends. All the best 73
OMG ... this is a salvation for this great RIG .. i sell my new one 7100 because he has low modulation deflection ... tanks a lot
+DJ Caverna Haroldo Bradaschia Neto Hi Neto, thanks for feed-back now you can buy your rick back :^) Thanks for watching 73
It is amazing what you can do when you know how well done :)
Thank you John, well time and bad documentation is always the limiting factor... 73
Jeder video die ich sehe ist wie eine neue lektion !
Sehenswert !
All videos to see it is like a new lesson !
Worth seeing !
You're awesome man, I love that you break down and explain everything and why you do things. Thanks!
Magnificent work/mod. Thank you.
Fantastic Video Peter ... Many Thanks ... One question ... I presume the little Fly SH.T resistor was removed and that you bridged the 2 points with the lead of the Capacitor ... Mike M0csi ...
Maybe we are so lucky that this modification made the modulation really clean and "unstrangeled" that the ALC now works as it should and that the "SSB-drive" in the setup menu have to be set lower because the factory setting had to be set way to high to compensate for the flaw in the ALC-design. (of course it was factory-adjusted with a pure tone fed to the mic-line and not a voice.. and therefore whistling in the microphone always gives 100w+ power output, and therefore Icom did not detect the flaw as they use a tone)
+Lars Johansson Hi Lars, all tests before we released this were positive. We tested different cap values and found 10uF to be good. Mod is clean even with compressor. 73
Vielen Dank Peter für die detaillierte Beschreibung. Exzellentes Video !
Vielen Dank Harry HNY 73
Another excellent mod/repair. It amazes me that Icom (or any high tech company) would allow equipment to be built with an inherent problem like this. People pay hard earned money to own a piece of equipment that should work for years without an issue. Especially an issue that doesn't have to due with age and or, wear and tear from everyday use. More testing before release of equipment would solve unnecessary failure. Manufacturer should catch poor design before the item is released for sale. Excellently produced video as always.
+4Q2 42Q Hi, yes I agree it is really a shame... Thanks for comment! 73
Did the mod to my 7100, had VE6JF do the work for me (Briillant Guy), went from 17w peak to 97w. Thanks for the detailed video - could not have done it otherwise. !! (VA6QAS)
Not seen a lot of you recently are you going to do more, I am missing your uploads
hi Peter,i know this video is old but i find it very helpful, i got a new icom 7300 that had the same issue right out of the box,i did the mod on it and i am very pleased with the end results,it was doing no more than 60 watts on ssb mode and now it does about 135 to 140 watts after the modification,i used a 4.7 microfarads 16v capacitor, will it work better if i had used a 10 microfarads capacitor as you used on the icom 7100? thanks for the great and useful videos Peter 73
So we have to consider that the Icom engineers knew about this, and they reduced the output power to correct a separate issue. If that was the case, the real issue might be that the increased power causes some other failure that Icom would be responsible for fixing on their dime. Only time will tell. So if somone makes this mod, and they give the radio a good SSB workout, if that causes a failure in some other related circuit, it would benefit all IC7100 owners to hear about it. I am not a heavy SSB user, and my main radio for SSB is the IC7600, my IC7100 was left for Dstar use only. Although, I have to say that Dstar on HF has been less than good on the IC7100, where SSB on HF using the IC7600 has been great on the same antenna. This MOD seams easy enough to make, but you have to wonder how it got past quality control at Icom. The only honest mistake could be if the original IC7100 had other parts, and at some point the quality of those parts had changed. The only way we could know that is if we hear from some of the first IC7100 owners and see if they had this same problem. The IC7100 has been out for a while, so a change in parts could be the cause of this RF problem. This is my opinion, so please don't flame me for it. Joe KQ4BX
+Joseph Massimino Other persons opinions are always welcome! I don't think that 7100 is having a weak Power stage that could burn if transmitting with normal levels on SSB. Maximum power output on other modes are really good on my 7100 and I can transmit for extended periods of time without detecting any unnormal sweating. I guess that Icom in some stage when designing the rig did not really consider the importance of finally testing the rig in real use before pushing the start button in the factory line. And the reason for this ALC-flaw can be as You said component(s) changing quality.. I am a real novice but as You I also try to understand how Icom could release a rig with this kind of serious flaw. When remembering the IC-2820 and it's low quality modulation that went really bad when Icom suddenly decided to ship the rig with the cheap China manufactured microphone, it looks like Icom don't care much about testing anything at all when changing the original setup.
+Joseph Massimino Hi Joseph, I agree with Mats comment! Thanks for watching 73
+Mats Bladh I fully agreed! Thanks 73
In my past experience i have increase the power in 4 radios to 200 watts ///kenwwod ts-50 // ts-930 and ts -940 ,,, and ft 1000...and never have any problem with them until i sold them...but i was heavy criticize for doing this,and almost all of this guys says that i will fry my radio in no time...that never happens...i am glad that he post this video,if i ever purchase this radio i will do this modification for sure,i take the risk...i need those 100 watts baldly no Mather what...but i also agree with your comment ,is very true,i respect your point of view//////,after this mod is performed only time will tell...73
Thanks a lot for this great video (Again!!), did you try same workaround on ic746 (non pro)? I found the power in SSB to be 40 to 60 Watts while 110 in RTTY. I located IC971b on POCV line but I'm unsure how to adapt your work. rgds, 73's G
Hi Jerry,
Great video. Very low average and peak power was the first thing I noticed when my new 7100 arrived. My solution was an amp but now I want to install in my truck. There is another RUclips video where the guy just did the jumper and not the capacitor. I thought your video said the jumper was for AM but his power went up on all bands SSB and the power delivery seemed more aggressive than your mod. What are your thoughts about just a jumper? Also, I am having trouble locating a radio shop to complete the mod. Do you know of any in the states?
Thanks again for your videos. I am learning much.
Brad
Hi David, I made the modification but after that the Radio no power output in HF, I have reversed the changes and same no power 0 Watts. Please let your recommendation to make a trouble shoot. TY
Hello. This modification also works on VHF ssb ??
Do you have a pic that shows the right lead soldering position better?
Robert, viele Dank für die Modifikations Anleitung. Es hat alles wunderbar funktioniert.
73 de Franz
Nice Mod to the ALC, The only thing I would do is add some RTV to secure the cap to the board as this is a portable radio and is subject to some harsh handling and can cause the solder joints to break lose or the pad to come off the PCBThanks Keith N9QDS
+Keith Schreiter Hi Keith, you are absolutely right but of course the cap has been fixed with hot glue! Thanks for fee-back 73
Brilliant ,, my ic7000 only does 60 pep. Cheers Shane
Hi Shane, good luck with the mod. All I have done are working perfect. 73
If surface mounted components get any smaller Peter, we'll need Electron Microscope spectacles in order to do repairs! LOL!! 73s Good Buddy.
+Nina Evans Hi Nina, lol you are right I almost need a electron microscope by now lol. Thanks for watching 73 and all the best
Icom 756pro3 the same problem. I wonder how to fix it on this rig? Someone does know?
I hope you put a dab of silicone rubber or equivalent on the capacitor where it meets the board or road travel movement from bumps will cause it to fail
Hi Peter thank you for another brilliant video
Can I ask you- what is the SSB monitor unit on the bench?
what does it do ?
thank you again- 73
+Nut Lock Hi, thanks for feed back! Regarding the SSB monitor you already have the links from the kind gents.. 73
hi, i am experienced electrical/electronic engineer, have the ic7100, would like to know is there any possible/expected damages in few years later after this modification done? and whats the different from your point of view if using 50uF or 100uF instead of 10uF capacitor? 73 de 9w8haz
Thanks for this video . Great Job
+Grant Fullen Hi Grant, thanks for stopping by 73
As always a great video
Thank you
+DENNIS N Always glad that you like it Dennis! Thanks for always giving me a feed back! 73
So what if I have no output at all on ssb? That is my issue. It works fine on digital modes but hf ssb phone mode I have nothing.
You are a genius! I've watched several of your videos and have subscribed even though I'm not likely to ever try by myself. Im brand new to HAM radio and found this video by chance since I just ordered an ICOM 7100 like an hour ago. I don't have an LP-100A...how will I know if my 7100 is suffering from this problem?
Hi Gerry don't worry the latest units do not suffer from this issue..
I know this is an old thread/video, I did the mod on my 7100, have a slight issue, wonder if anyone else has this.. I have the Icom AT180 and a diamond mobile antenna, with the mod'ed radio, when I key (very noticeable when I use the SWR test) the power and tune bounces very rapidly on the bar graph. when I use it to talk the tuner will cut in and out and then the tuner goes out of line alc exceeds the limit and then cuts power. remove the capacitor and all back to normal.. is this a bad capacitor, or rf getting back into radio. mod removed at moment, any thoughts? thanks
what does signal look like on the spectrum analyzer now?
dear , is the ic-7300 is the same modification? it seems to be the same unit?? i need your helping
BR
Hello Peter, thank you for this video that I have just discovered. If I understood the fault comes from the circuit which limits the power when the SWR is high. Do you confirm that after this modification the power circuit is no longer protected?
Indeed I am going to use an IC-7100 with an AH-4 and I am afraid at the beginning of the tuning of the tuning box the ROS being high this destroys my RIG. What do you think of that?
After the mod the AH-4 doesn't work properly.
I wonder if this modification does have any effect on ALC function also in DV and FM- mode? I hope it does because I hear many IC-7100's having issues like unclear blurry distorted characteristic sound when I listen to other ham operators.. It sounds like over aggressive limiting of the modulation level that adds "artifacts" to the modulation. So, could it be that this is the same reason why it limited the SSB-output so hard and that both problems will be taken care of when adding this modification? Or maybe just maybe this modification only affects the SSB and that Icom have made a similar error elsewhere in the design? (I imagine that the reason why Icom did not detect this error are because a signal tone-generator and not a real wider voice-like signal is used when designing and adjusting the level of modulation and setting when the limiter should start to work). The SSB power is ok when whistling, but when a wider signal is input, like a voice it gets limited way to early).
+Mats Bladh Hi Mats, all over the air tests also on FM sounds crisp and clear without any problem. Thanks for stopping by 73
like OMG he said Fly shit...
i never laughed that good in a long time.. thanks for the comedy :-)
+Scott Edick LOL, you are welcome, glad you like my comedy :^)! 73
+TRXBench We use the very same expression about those fly poops : )) LOOL
Wondering if this is still a problem I don't have a pep meter so couldn't test
Peter, another great video. Did you check the output with a spectrum analyzer after the mod? Just wondering if you are now over driving the PA?? I probably would have used thin #30 wire to connect the new cap to the SM resistor. I would also glue down the new cap. Maybe you did all this or equivalent but didn't show it? 73's KA2ZOH
+Herbert Susmann Hi Herbert, yes of course, we tested this mod before release extensively. IM3 with compressor is 28-29db and without compressor 31-35db related to the avg single tones of 44dbm in test configuration. If you would like the calculation on PEP simply add 6db to my test figures. Yes cap is fixed with hot glue. Thanks for feed-back 73
+TRXBench sorry 31-32 db!
+TRXBench I should have figured your usual thoroughness meant that this was already checked out. You never know with this stuff and since it wasn't mentioned in the video I thought I should ask so others might see your answer also. 73s
+Herbert Susmann Hi Herbert, no problem and nothing wrong with asking and rather more I should have mentioned it in the video so it was my fault. Thanks for your comments! All the best Cheers and 73
Did mod some months ago along with N type for VHF /UHF connector and clock battery mod . 7100 spot on now G8HUA
Hi Mike, glad that it works for you. Thanks for watching and comment. 73
Great video as usual.
+Gary P Thank you Gary!
Well done Peter! Question: Where did you obtain the block diagram, schematic, and PCB layout? I would like a copy myself to review. I have a 7100 on order and I eager to perform this mod. Thanks again!
+Scott Saunders Hi Scott you can find it on the web.Thanks for stopping by 73
Hi is this mod can that be done for the Icom 7410 with the ALC overshoot which my IC7410 suffers from.
Thanks for sharing Peter. We are honoured this week with 2 videos. Keep up the great work.
+rupert handford Hi Rupert, thank you very much! I try my best :^) 73
Do you get schematics or service manuals from Icom or any other vendor?
Another great one Peter. See you later, Greg
+Gregory West Thank you Greg. 73
Hello Peter, nice work !
I have a question, why have you bridged the transistor ? Why not just put the capacitor to hold the voltage and make the alc slower , isn't that enough ? If the transistor is used for AM mode control shouldn't you have left it like it was ? Thanks and 73!
+CT1ELP Hi Pedro, it is important to get the right balance between speed and performance. The mod will work as well if you put in the bridge only but it is not so efficient. If AM is engaged the transistor is switched on that is like a bridge.. so no problem. Hope that helps 73
Hi Peter, A great mod on the ALC line. however, with the pa now producing about 135W + PEP how hard are the PA transistors being driven or maybe over driven? And also, It would have been nice to see the spectral purity of the transmitted signal. Maybe Icom had to limit the power to meet spectral purity specifications? A before and after video of the transmitted signal quality would have been nice to see, especially if the radio is to be used for Data transmissions FT8 RTTY SSTV etc? Last thing any ham wants is poor IMD and a splatter box!
The THD is still in it specs and even 3rd IM products are still fine.
Adding the jumper AND adding the capacitor breaks the AH-4 tuner functionality. The RF comes up slowly when the Tune Button is depressed and the AH-4 times out (rather rapidly). I left the jumper on across the transistor but removed the capacitor.
Same experience here : I always leave in the cap ( 10uF multilayer ceramic) but omitted the short.
Why would the manufacturer design the radio this way?
I'm confused as well. Just speaking into the mic to try and determine SSB performance doesn't work, it requires a 2 tone continuous signal. Plus I can't help but wonder what does the received audio sound like after the mod?
Maybe compliance and alignments at lab to avoid RFI or some spurious emissions. Now with better home technologies, CB-ers get away with high power amps. Some IC-7300 for example has 25 watts in AM while the IC-7100 has 30 watts, some state 40 watts?
@@k2icc That still doesn't answer the question of why a radio manufacturer who markets and sells a transceiver touted to have 100 watts RF output can't do what it's advertised to do without modification. Nearly all 100-watt transceiver put out at least ONE-HUNDRED WATTS (or better), yet this model falls short. Just makes no sense why that is.
@@greenrefrigerator Unless people like you and me bring those things up, no one will listen to it or will care, to be honest.
There is a lot going on. In plain words, a certain percent of power at a certain mode, could be considered legally what they state. For example, my internet provider sells me up to 400 Mbps. So, I don't get 400 Mbps, but close to 380, and still legally stated.
So, they could state, due to some kind of whatever spurious or this or that, the reason for the values. This guy on the test knows what he is doing, so he can do what most can not do, as the equipment needed to prove the radio has certain amount of power, and that on a new radio can void the warranty, etc.
Hi Peter. Thank you for your video. I did this mod a long time ago after watching your instructions and it really works. This is really a great radio and I'm sure with new versions Icom has incorporated your modification in the latest design. I will check the latest Service Manuals and tell you if I find it. Thank you again. Well done well presented 73! de ZS6PVT
Peter - have you listened to the audio quality after you made the mod to see if there was any indication of distortion or did it remain clean? 73 - Dino KL0S
+Dino Papas Hi Dino, yes you can be assured we have a 100% clean modulation even with compressor on an mic gain on 100%. We have extensively tested it before release. IM3 products are also clean. Thanks for asking and for stopping by! 73
Interesting video Peter, does the mod not stress the PA? 73 de John G4YDM
I think I have same problem with TS-590, Any idea?
OMG!!!! Peter You did it!! THANK YOU VERY MUCH !!!!!!!
+Lars Johansson Hi Lars, hope that will solve your problem! 73
It sure did, more than the expectations I had ! Good reports from now on when I am using the 7100 on SSB/HF bands
Did you put the bridge in front of 1508 on top of that hole on the PCB. Thanks Art. Last question😀
oh wow Art, I can't remember sorry
there is a via next to the resistor that the cap needs to be soldered to. is it ok to solder to that via?
where ever it is suitable..no problem. 73
Great !!! Thanks Peter, 73s !!! Your friend Pasquale IW0HEX
+Pasquale IW0HEX Thanks you my friend! All the best 73's
Hello Peter, I'll be doing the 'Fly Sh-t' mod at the radio club tomorrow. Thank you for the info and I'll let you know how we get on. 73 from Colin 2E0KOL.
Hello Colin, very good! Good luck for the project! 73's
WHAT IS THE MARS CAP MOD FOR THIS RADIO?
But what if the antenna is only a 100W antenna--did you not just create a situation where it's going to be overdriven by the radio?
This Radio is perfect!
Here is the respond from Icom about the TX low power.
Thank you for contacting Icom America.
Icom's position is that the model 7100 is operating according to it's specifications and it's design. The firmware that you mentioned only allows the meter to operate with a faster sampling rate, it does not provide a "cure" or "fix" because (in Icom's opinion) the radio is not broken. We do not support the modification of the radio, and Icom could not do any such modification however, if the operator chooses to have it modified, that would be their choice. We appreciate your understanding.
And that is why I refuse to ever spend my money on a new Icom, I will only buy used and put my money in private hands, I greatly dislike Icom's attitude.
I Bought a IC 7410 and I sometimes wonder if I should have purchased a 7100 . I see or I don't think it has a built in antenna tuner, that is a con I am perfectly happy with my radio I only like the Dstar option and the uhf vhf option. Maybe some day I will purchase a IC-9100 that has it all. I guess I have some deciesions to make. I will really hate to get rid of my 7410 it has been flawless. N3SXW
gr8 video....icom 7610 has same issue .will you be doing a video for ic7610 ???
So does the 7300, mine went up to 127w pep from a previous max of 96w pep and everyone noticed how much richer was the bass in my audio after the ALC mod.
Hello. Mounted 10 microfarads, on the transmission there are bad spitting sound on self-control. Mounted 1 microfarad was excellent ALC. Put 1 microfarad!
I just bought an Icom-7100 because I wanted a new radio for my vehicle. Bought 12-Dec-2021. I also bought the optional HM-151 microphone. Full 100 watts output without compression. This was transmitted into a dummy load. I also sent the microphone to have Bob Naggy modify the element, add an ounce of extra weight to it and he also drilled the hole larger in the mic face and put more of a filter behind it. It now keeps the breathing and spitting sound away. I do not understand why my radio and others transmit the full 100 watts out while others complain.
There is an upgrade to the firmware in 2016 but I think it was before this video was uploaded. I understand and have tested the stock HM-198 and find it really is not a good match to the radio. The optional HM-151 is and after the modification to it, it is excellent.
Don't modify the radio because it has a poor stock mic!
The newer radios don't have this issues any more Icom has modified it..
Peter..I had to do a very similar mod on my ft-901 to get full power on 40m.
The alc was kicking in too early. I added a cap.
+Doctor Forbin Hi, yes to make a ALC slower is a well known procedure..So no rocket science lol 73
from what i am seeing they still do this new... how is this not a recall?
Mate just got one last week same deal... I saw the lack of current draw and knew immediately
you have top notch Chanel love it keep up and as well you answer comment vy 73 ilan
Thank you Elan really glad that you like my videos!
Thanks for the reply ,, I won't be doing any mod ,, incapable ,,, will have to pay someone thanks Shane
Wonder what the peaks of the ssb envelope look like... Seems the peaks would be clipped & only limited by the PA's maximum voltage capability without the ALC reducing drive... Are you able to do a follow-up video showing the output on a scope with this modification? A theory I have is that one could 'trick' the ALC threshold by doing a 're-alignment' of the output power calibration procedure on the ic-7100 using 130 watts & scaling it for the lower power calibration points to accomplish similar ends, while also keeping the ALC intact. I guess I'm lucky though, my ic-7100 produces it's rated output, but I agree that the ALC on SSB is finicky w/ certain settings.
+DDSPL15 Hi, we tested this mod before release extensively. IM3 with compressor is
28-29db and without compressor 31-32db related to the avg single tones
of 44dbm in test configuration. If you would like to have the calculation on PEP
simply add 6db to my test figures. Audio was tested on the air crisp and clean. Thanks for watching 73
+TRXBench At what power output was this conducted at? I wouldn't expect IMD to increase w/ this modification if the output power remains below the maximum voltage swing of the PA; THD can even decrease slightly as you get closer to maximum voltage swing on a Class AB amplifier. However, without ALC limiting, the only thing preventing a clipped output is the maximum voltage swing capability of the PA, unless one manually turns down RF gain to prevent the peaks from trying to exceed maximum voltage swing of the PA.I guess the IC-7100 could also do RF output limiting via Id current sensing, but I'm unsure of this and the peaks of the SSB envelope could be just as clipped depending on how it is implemented in the DSP and/or CPU. The PA output devices in the IC 7100 are rated at 70 watts w/ a 12.5 Vds, they are in complementary Class AB configuration which could "safely" allow for 140 watts PEP output under IDEAL conditions; my guess for the reason why 140 watts was the peak output you measured was likely due to some sort of programmed 'fail safe' hard current limiting of the output devices, thus no more current, no more voltage swing. If this Id current based RF output limiting is being implemented via the DSP by reducing IF output gain in a similar manner to how the ALC functions, then I guess the PA output could still be relatively clean on the peaks so long as the DC power input voltage was sufficient to maintain Vds voltage headroom. All of this is just a guess though, but I'd bet even w/ this mod that you won't see more than 22 amps of Id, which happens to be the maximum spec for the radio & likely programmed to be the limit as well.
Did you look at the SSB envelope on a scope w/ audio, or perform any maximum power transient / pulse IMD measurements? I hope I'm not coming off to be negative about your video or your work as I do enjoy your channel; I just want to make sure everyone understands the full picture of what this modification may be doing to their transmitted signal :)
One more question Peter. You used a 10uF 50V capacitor, what is the lowest voltage capacitor you would recommend? Would a 35V be OK? 25V?
73 VK5ZEA
+Michael Carey Hi Michael, well a 25V cap is fine no problems. Good luck with the mod. 73's
+TRXBench Thank you once again! 73
Hello, very good work and explanation, congratulations. I have a question about IC 7100 and this change made is about updating firmeware released by ICOM to resolve this low power, I do not comment your I was curious to know if would have to make its modification along or not the update of ICOM, thanks.
+Carlos F Jr Hi Carlos, you should do the firmware upgrade in any case first and see how it works. Our experience is that the difference is not that huge. After that you can go for the hardware mod. Thanks for watching and feed-back 73
Great video as usual, while I don't own the radio in question it's always informative to see the schematics and learn a little more.
Would it have been easier or neater to add a ceramic MLC part instead of the electrolytic I wonder?
Thank you Clint. Well a10uF cap is not available as ceramic type that is the problem... All the best and Cheers.
I have to respectfully disagree, there are many ceramic 10uF capacitors available, in fact the values go up to 220uF 25V and possibly higher, however I did make a small mistake, I missed off a C, I should have typed MLCC.
Clint, off course you are right where was my brain LOL. And yes it is possible to use those caps. I simply don't have them on stock :^) . So completely my fault sorry. Cheers
@@TRXLab Most definitely not true, they are readily available. A Kemet 10uF ceramic 805 SMD 16V capacitor - RS part number 691-1161 cost 10p each, currently 5000 in stock, 1 day delivery here in the UK - and many other makes also available. But as has been mentioned, 10uF is far too high a value to achieve what is required.
I wonder who will see the difference of 1.5dB on the receiving site.
peter, I just want to understand, if I do this mod does it effect transmit power on other bands and mode. thank you/ Art K2ADC
Hi Art, it will affect the SSB modulation and thus the power on SSB that's it. Hope that answers your question. 73
Please do a video for icom m710 for this modification
Outstanding. Muy bueno.