Programming volatile memory boards in older Icom Rigs and radio upgrades

[Radio Tech]

Now the next step is to hack the firmware to enable RX below 100 KHZ.

I have done a LOT of reading on the 745 over the last year.  There is a bit of code located in address 000 that contains the upper and lower band limits for 160 meters.  At least on the R71 receiver which uses the same ram board.  From what I read by shifting a "1" to the left by one place it will change the lower band limit. 

Now that I can play write  the board I can give this a shot and see. Worth a try.

[AF6LJ]

Now the next step is to hack the firmware to enable RX below 100 KHZ.

I have done a LOT of reading on the 745 over the last year.  There is a bit of code located in address 000 that contains the upper and lower band limits for 160 meters.  At least on the R71 receiver which uses the same ram board.  From what I read by shifting a "1" to the left by one place it will change the lower band limit. 

Now that I can play write  the board I can give this a shot and see. Worth a try.

I'd like to see it carried down to 1KHZ.

[HighPrecision]

A big thanks to HighPrecision and thumbs up to you 

Again, Thanks for your words Buddy !

I wil add here the KiCAD files of the PCB and generated gerber files for production, please note that there is NO schematic in the project, only pcb.

Good year 2018 to ALL !

[Radio Tech]

Again, Thanks for your words Buddy !

I wil add here the KiCAD files of the PCB and generated gerber files for production, please note that there is NO schematic in the project, only pcb.

Good year 2018 to ALL !

Great, I am going to get a few boards made up.
Not sure if I will make them myself or just send out for them.  If so I will but a little bonus mention on them
Than you very much.

Next thing I want to do is  break the code down completely. And yes been many years since I done that.  I want o know what every byte in this does and what function it provides.  This will get us closer to Sue's request on lowering the receive frequency.  I really do not see a reason why the radio will not receive down further and looks like it is only firmware controlled.

I have not started with the Arduino yet but we should be able to make a custom shield, so after the software is done the whole thing should be plug and play.

You guys just do not know how excited all this has made me.  I appreciate each and every one of you here. 

[Co6aka]

Please post your 745 dump; if it's like the R71 it'll be obvious.

[Radio Tech]

I think we need to look at the modified file? I will try and play around with it today or tomorrow. Not sure if I can even get into the shop today due to recent snow storm.  Also have to remember how to convert these files.

[stj]

you know, you could replace the ram with a microcontroller and program it through usb?

[Radio Tech]

you know, you could replace the ram with a microcontroller and program it through usb?

That is very true yes. But if we are going to do that then best to just rip put the entire logic board and build one from scratch.  This would do away with a lot of the limitations. It is something I like to do down the road.

[AF6LJ]

The IC-745 is a very good performer for its day and for now.
Two things could be done to improve the radio and bring it up to date.
Replace the radio's controller subsystem.
1. Eliminate the Matrix board, this board manages much of the front panel digital operations and supports the scan function.
2. Replace the logic board with on board support for the front panel digital functions, and an 80 column display.
A. Upgraded display that will support multi line data display.
B. Upgraded synthesizer buss supporting a VHF DDS usable to 1HZ increments.
C. Provide CAT interface with an instruction set compatible with the IC-756, allowing use with HRD. (Ham Radio Deluxe)
D. PTT delay for safe amplifier operation. (for those who may not know this radio and other radios of its vintage are known for generating large RF spikes during T-R and R-T transitions. )
E. On board keyer.

The other issue that would add value to the radio was touched upon above. Replace the PLL board with modern DDS.
While we are at it, a second LO upgrade would be in order.

[German_EE]

And a pony 

[Co6aka]

For the R71, the frequency expansion is...

30/31 = lowest frequency (factory is 100kHz)
3B/3C = highest frequency (factory 30MHz)

To change the lower frequency limit from 100kHz to 10kHz:

Original - 000: 00F1FF1FF002FFFF000B59686800032005930005000000000100000030003000
Modified - 000: 00F1FF1FF002FFFF000B59686800032005930005000000001000000030003000


To change the upper frequency limit from 30MHz to 35MHz:

Original - 000: 00F1FF1FF002FFFF000B59686800032005930005000000000100000030003000
Modified - 000: 00F1FF1FF002FFFF000B59686800032005930005000000000100000030053000


If merember correctly the transceivers had a similar entry for each ham band... It's been too many moons since the good-ol-days though, so I'm likely mistaken.

[Diabolo]

Hello,

Thank you for your instruction and expertise.

Regards.
Diabolo

[Radio Tech]

Sue, Nice healthy list. Would really make for some nice improvement's to the IC-745.
I really agree with the second LO upgrade. The stock circuit is bare bones at least to say about it.
We have to get this in the works and turn this thread into a 745 makeover thread.

German _EE,
Got to include a pony 
BTW, I need to email you. Just so many mails here. 3k this week. 
No idea why I get so many. 

Hello,

Thank you for your instruction and expertise.

Regards.
Diabolo

You are quite welcome. 
I am not speaking for myself but for those that have contributed so much in this thread.

[AF6LJ]

My to-do list is ambitious to say the least.
 

[Radio Tech]

As of right now I am playing with some modified code. Working on the band limits.  Where did you want to receive down to Sue .
If the PLL stays lock we may have a winner.

[German_EE]

As we can see the best way to keep warm is a workshop full of Hammarlund gear powered up in one corner whilst testing an Icom receiver to its limits on the bench. much more fun than turning up the heating.

[AF6LJ]

1KHZ If you can do it, I'll get a battery for the ram module I have here and have you program it.

[AF6LJ]

As we can see the best way to keep warm is a workshop full of Hammarlund gear powered up in one corner whilst testing an Icom receiver to its limits on the bench. much more fun than turning up the heating.

Yes it is...
Almost as much fun as chewing the rag with friends while the Heath SB-101 and SB-220 are running.

[Radio Tech]

As we can see the best way to keep warm is a workshop full of Hammarlund gear powered up in one corner whilst testing an Icom receiver to its limits on the bench. much more fun than turning up the heating.

Oh yes, that should do the trick. Have to fire up the Johnson's and the Swans also. It is a frigid 18 degrees F here at the moment.

Here is something I have not seen since I was a kid here.  Went to the dump a moment ago and  the roads here are still under 3-4 inches of ice and snow. I then crossed the river bridge and snapped this picture below. I have not seen that river frozen over in many years.

I am going to call it a day here in the shop. Been running back in and out of the house helping the wife with the grand kids. 

[Radio Tech]

1KHZ If you can do it, I'll get a battery for the ram module I have here and have you program it.

Cool, I am shooting for 0 starting frequency and see where it goes from there.  May be tomorrow evening before I can go any further.
They say it will e a toasty 44 degrees tomorrow
I am going to get some more batteries and weld some leads onto them myself.

[AF6LJ]

1KHZ If you can do it, I'll get a battery for the ram module I have here and have you program it.

Cool, I am shooting for 0 starting frequency and see where it goes from there.  May be tomorrow evening before I can go any further.
They say it will e a toasty 44 degrees tomorrow
I am going to get some more batteries and weld some leads onto them myself.

Sounds good, looking forward to seeing your result.

[Radio Tech]

If all goes well this evening I will try the new file out.
So frigged cold here. Should warm up to mid 40s. Will be the first time out of freezing.

The file is already to be loaded into the ram board. We will see what it does. may record and upload.

[AF6LJ]

If all goes well this evening I will try the new file out.
So frigged cold here. Should warm up to mid 40s. Will be the first time out of freezing.

The file is already to be loaded into the ram board. We will see what it does. may record and upload.

You guys are getting tossed in the deep freeze back there.
I wish we had some of that out here.

[Radio Tech]

If all goes well this evening I will try the new file out.
So frigged cold here. Should warm up to mid 40s. Will be the first time out of freezing.

The file is already to be loaded into the ram board. We will see what it does. may record and upload.

You guys are getting tossed in the deep freeze back there.
I wish we had some of that out here.

I wish you could have it
It has not been this cold in a long time. It finally got out of freezing today. Upper 40's. By this coming Friday low 70's. Woohoo 

[AF6LJ]

If all goes well this evening I will try the new file out.
So frigged cold here. Should warm up to mid 40s. Will be the first time out of freezing.

The file is already to be loaded into the ram board. We will see what it does. may record and upload.

You guys are getting tossed in the deep freeze back there.
I wish we had some of that out here.

I wish you could have it
It has not been this cold in a long time. It finally got out of freezing today. Upper 40's. By this coming Friday low 70's. Woohoo 

It sprinkled here today for a time, supposed to rain tonight.
Rumor has it we may get an inch or more.
/Sue is not holding her breath.