ICOM IC-7300 LOW SSB POWER MODIFICATION
v.1.0 ©SP3RNZ written & published Feb.2107
sp3rnz@gmail.com sp3rnz.blogspot.com
If You are owner of 7300 this MOD should make You more happy looking on your small Icom7300, not to mention about saving your throat screaming loud to get more than 30W on SSB.
Quite dissapointing serious factory fooling their users saying that screwed ALC unit is madeto comply with the high standards of spectrum purity and A class signal.So what about their other radios, i.e 746, 756 or any PRO series? Are they piece of Sh!&^and should not be used? Kind of bullshit IMO.
At this point I need to pass my sincere KUDOS to Marios SV0CL for hispriceless hints, discussion and help.
Here's a solution - SSB power increase MOD, born after long hours spent on examiningschematic diagrams, comparing circuit details and ham radio cooperation.Likewise as in IC-7100 low SSB power ( but not only SSB - i.e FSK441 and JT6M also areaffected) it's the problem of too sharp ALC limiting, making the ALC loop acting too fastto let the signal envelope to rise enough. And it's not the matter of MIC gain setting norPROC value. As You probably seen on the video posted in December difference in averageSSB power is HUGE at first sight.Take note that MIC gain and PROC settings after modification remains in LOW rangecomparing to this what we can find on various websites concerning low power on SSB,and we are still within 75% of ALC scale! Doing MIC gain at 90% and PROC at 6 can causeonly screwing signal on the air and sort of splatter around.
WARNING :
Any mistake can cause serious damage to your radio. So if You arenot experienced in SMD soldering or using soldering iron at veryFRAGILE enviroment - do not try to perform the operation! I will benot responsible for any damage You can make doing the MOD.
We need to prepare tantallum capacitor, magnifying glasses, and a value of 2,2-4,7uF /16Vwill do the job for us. The bigger capacitance, the slower ALC rise time.Test proved that 3,3uF works well and could be optimal solution, but 4,7uF will be good aswell. Various tests proved that we may use ordinary electrolytic capacitor also.
v.1.0 ©SP3RNZ written & published Feb.2107
sp3rnz@gmail.com sp3rnz.blogspot.com
If You are owner of 7300 this MOD should make You more happy looking on your small Icom7300, not to mention about saving your throat screaming loud to get more than 30W on SSB.
Quite dissapointing serious factory fooling their users saying that screwed ALC unit is madeto comply with the high standards of spectrum purity and A class signal.So what about their other radios, i.e 746, 756 or any PRO series? Are they piece of Sh!&^and should not be used? Kind of bullshit IMO.
At this point I need to pass my sincere KUDOS to Marios SV0CL for hispriceless hints, discussion and help.
Here's a solution - SSB power increase MOD, born after long hours spent on examiningschematic diagrams, comparing circuit details and ham radio cooperation.Likewise as in IC-7100 low SSB power ( but not only SSB - i.e FSK441 and JT6M also areaffected) it's the problem of too sharp ALC limiting, making the ALC loop acting too fastto let the signal envelope to rise enough. And it's not the matter of MIC gain setting norPROC value. As You probably seen on the video posted in December difference in averageSSB power is HUGE at first sight.Take note that MIC gain and PROC settings after modification remains in LOW rangecomparing to this what we can find on various websites concerning low power on SSB,and we are still within 75% of ALC scale! Doing MIC gain at 90% and PROC at 6 can causeonly screwing signal on the air and sort of splatter around.
WARNING :
Any mistake can cause serious damage to your radio. So if You arenot experienced in SMD soldering or using soldering iron at veryFRAGILE enviroment - do not try to perform the operation! I will benot responsible for any damage You can make doing the MOD.
We need to prepare tantallum capacitor, magnifying glasses, and a value of 2,2-4,7uF /16Vwill do the job for us. The bigger capacitance, the slower ALC rise time.Test proved that 3,3uF works well and could be optimal solution, but 4,7uF will be good aswell. Various tests proved that we may use ordinary electrolytic capacitor also.