Awesome Idea the si4732 integration 🥇

[iu0azb]

Hello phdlee, I discovered your firmware here on github almost by chance. since I have a k5 dedicated to testing and a si4732 in the drawer, I'll try to put it in place of the original chip! I just have a doubt about the work around the chip.. Looking at the shematic around the actual BK1080, it would make sense bypass or adapt the Q7 circuit.. and replace C28?
Last, if you could share a picture of your PCP modified it could be helpful to have a clear idea :) Sorry to have used the issues form but it was the easiest way to contact you :)

[alboc2k]

Someone was too fast then us 😳

https://a.aliexpress.com/_Ey5oFHF

This is unfair, but maybe more OM will mod their radio, expanding the community. Anyway, maybe someone will make a "open" version of the PCB so more and more OM can have the PCB at the ceapest price and with greetings to Ian

[phdlee]

Excellent For experiments, I am planning to convert my UV-K5 to a dual antenna in the same way as you.

I plan to increase the impedance of the Antenna In that goes into SI4732-A10. (It was done that way a long time ago, and it has the effect of greatly increasing reception performacne. However, increase interference with FM broadcasting and AM broadcasting )

On Thu, Feb 22, 2024 at 6:53 AM iu0azb @.***> wrote:

At the end of a day spent to understand the problem I decide to bypass it, adding a dedicated SMA in the LED spot 😊. For who want to try, be informed that there is almost no space between case and pcb/lcd flex. The back of SMA need to be plunged inside plastic and back need to be modified to void any extra space other than central wire.

Cool working result.

907E46C0-F503-4D79-A02D-29162C1416A7.jpeg (view on web) https://github.com/phdlee/uvk5cec/assets/63300383/13af8f29-accf-41ef-b26f-c8c1a33ba37f

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[phdlee]

IU3POA I also agree with your opinion. Usually, products using SI4732-A10 use a telescopic antenna. While working on SI4735 (same SI4732) a few years ago, I increased the impedance so that it could receive very sensitive signals. However, the signals from stations with strong signals were all distorted. However, I was very satisfied with USB/LSB (SSB).

Be sure to send me your mods and videos. It will be of great help to many people who want to modify for HF reception.

Ian KD8CEC

On Mon, Feb 26, 2024 at 5:59 PM alboc2k @.***> wrote:

Hello Ian, I made the mod and it works quite well. If you like, I can send you some videos and photos. It dosen't look pretty, but it works. Probably I'll go for a sma port like Luca did.

Things to mention/suggestions:

1. add some sort of memory for Commercial FM and for band VFO
2. More use of keyboard instead of menu+side buttons.
3. Like said by Luca there are some noise/click, so maybe a sma port should be better.
4. With (hi gain) antennas loks like there is some sort of saturation. Again, maybe point 3 resolves
5. a notch for FM or (better) a bandpass filter is mandatory with hig gain antennas

Thank you for your wonderful work!

73 de IU3POA.

photo1708765195.jpeg (view on web) https://github.com/phdlee/uvk5cec/assets/18322550/a8bbf343-46b8-4da4-adbd-62e7662b7208

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[phdlee]

thank you for the information. It is expensive, but I think it will be helpful for people who have difficulty soldering. I'm quite impressed that you scraped the PCB and connected GND. I think it will be easier to work that way. Ian KD8CEC

On Mon, Feb 26, 2024 at 10:55 PM iu0azb @.***> wrote:

Someone was too fast then us 😳

https://a.aliexpress.com/_Ey5oFHF

— Reply to this email directly, view it on GitHub https://github.com/phdlee/uvk5cec/issues/6#issuecomment-1964203620, or unsubscribe https://github.com/notifications/unsubscribe-auth/AE4DZPE3YA6VYWPBLV4KKA3YVSH37AVCNFSM6AAAAABCCJD6GCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSNRUGIYDGNRSGA . You are receiving this because you commented.Message ID: @.***>

[alboc2k]

I've just made a prototype similar to the chinese one (a copy of copy? :-D Some tests needed...

I've put some credits to Ian in the back.

It's a first try and I'm waiting for some errors report from JLPCP. I assume that castellated holes are needed, but I'll go without, just because they make the PCB too much expensive. Also, if all works, I'll post results. Once defined price should be around 10€ for 60 (panelized).

[iu0azb]

At the end of a day spent to understand the problem I decide to bypass it, adding a dedicated SMA in the LED spot 😊. For who want to try, be informed that there is almost no space between case and pcb/lcd flex. The back of SMA need to be plunged inside plastic and back need to be modified to void any extra space other than central wire.

Cool working result.

Overall after a week of test I'm quite impressed for reception results in portable operation with 50cm whip antenna on dedicate antenna connector. Next step is to add a 30mhz lpf to mitigate FM intermodulation... and rethink the Q7 circuit as hf dedicated preamp.. Hope to find time to put in place ideas 🙏

[jh4vaj]

I made it with Flex PCB. It seems to be working, but the sensitivity is remarkably low. will investigate the cause of this.

Other issues include

FM radio: side up/down buttons do not work properly (same behavior as Exit button) Exit: It appears to exit on the display, but the sound of the radio broadcast continues to be heard

I have posted the details on my blog. It is written in Japanese, but you should be able to understand most of it from the photos and figs.

You can also download the gerber file from my blog.

https://www.jh4vaj.com/archives/42905

[iu0azb]

For the audio that remain exiting from the HF mode I noted that depend from dual HF menu enabled.

Also I don't see that you removed the two components just before pin6.. you can improve bit more the reception

The flex pcb you made is really nice 😎.

[jh4vaj]

I overlooked the 'HF Dual' menu. I set it to 'OFF', the HF reception ended with 'Exit'. By the way, when 'HF Dual' is 'ON', I hear a very loud noise ('pata-pata'). Even in 'HF mode' reception, I can hear it, albeit faintly. What could this be? Is it a problem specific to my UV-K5?

The issue with the reception sensitivity in 'HF mode' was due to my soldering. The pin-8 (AMI) of SI4732-A10 was not properly connected. I apologize for the confusion. The two components I removed are 'MOD. S1'.

By the way, could the function of the side Down button (F2 button) be assigned to another button? Under Japanese regulations, we must prevent transmission outside the amateur band. After setting that state in the UV-K5's hidden menu, we need to block access to the hidden menu. Therefore, I have to cut the wiring to the F2 button and physically disable the F2 button. Of course, this applies not only to the HF version but to all. I would be very happy if you could consider this.

Back and forth, you can download the gerber file for that Flex PCB from my blog. If you're interested, please give it a try.

[jh4vaj]

Sorry. I misunderstood a bit. The picture above is before the mod.S1 was implemented. MOD.S1 was then performed. In other words, I have removed those two components. The very poor reception was, as I wrote earlier, a problem with my poor soldering.

[phdlee]

I'm glad it's working well. If the sound is a little quiet, you can short the resistor connected to pins 3 and 4. There will be no bad effects because there is a capacitor before going to the Audio Amp.

HF Dual is an experimental feature. Please disable it.

The HF Dual function was created to test a Real Dual Receeive(as Kenwood or icom - highend class transceiver). Rather than monitoring the frequency by toggling A/B and activating the receiving side like a typical dual watch, this is a function that allows A/B simultaneous reception (reception from vfoA and vfoB are heard together) found in high-end radios. To do this, you need to mix the audio volume of BK-4819 and SI4732-A10. I was testing it. If I can increase the free space of the program a little more, I will do more testing and either complete this function or remove the menu.

2.Activate/deactivate the firmware with the Hidden menu and then re-upload it with the firmware with the Hidden menu removed, wouldn't the legal problem in Japan be resolved?

Ian KD8CEC

On Sun, Mar 3, 2024 at 4:14 PM jh4vaj @.***> wrote:

Sorry. I misunderstood a bit. The picture above is before the mod.S1 was implemented. MOD.S1 was then performed. In other words, I have removed those two components. The very poor reception was, as I wrote earlier, a problem with my poor soldering.

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[jh4vaj]

If the HF Dual function is to be implemented, it may be necessary to allow independent adjustment of A/B volume.

I'm talking about something that may have to do with sound-volume. Currently, the SI4732's Rout are connected to both 3 (ROUT) and 4 (LOUT). How about connecting the Rout of the SI4732 to 3 (ROUT) and the Lout to 4 (LOUT)? Would this not make sense? Or will it cause some problems? I would like to experiment with that connection if it does not cause any particular problem.

Two other issues I noticed are

• AM and FM broadcasts are received well, but SSB (HAM radio) is extremely low volume (both LSB and USB).
• The Up/Down button on the side does not work while receiving FM broadcasts. It exits from HF mode.

As for how to deal with Japanese law, I cannot say exactly because it is not explicitly stated in it's details and I am not in a position to judge the law. However, I understand that what is required is that "off-band transmission cannot be easily performed. Therefore, firmware without hidden menus could be a suitable approach. More correctly, only "F Lock" option should not be present among the hidden menus.

[iu0azb]

Hi, Let me partially reply based on my experience. Since uvk5 is mono, it make no sense spend time to split the signal till the two resistors. In all my samples I connected the audio just after the resistors to increase the audio output.. I noticed too that in ssb the level is almost the half of AM. I remember there was a value in the library to adjust it but need to check.

😊Luca IU0AZB

[jh4vaj]

Thanks a lot. I figured that if there is an audio signal (even if it is mono) output from both LOUT and ROUT on the SI4732, then using both of them might increase the volume. I designed my PCB to allow for both "ROUT - 3, 4" and "ROUT - 3 / LOUT - 4" wiring. However, I am not familiar with the SI4732, so I cannot determine if the latter connection would cause any problems.

[alboc2k]

Hi, Let me partially reply based on my experience. Since uvk5 is mono, it make no sense spend time to split the signal till the two resistors. In all my samples I connected the audio just after the resistors to increase the audio output.. I noticed too that in ssb the level is almost the half of AM. I remember there was a value in the library to adjust it but need to check.

😊Luca IU0AZB

I see there are a lot of settings for SI chip. I think future releases of FW will adjust a lot of nounces we are experimentig, hoping flash space will suffice. For example I experiment a lot of freq offset in 20m. Maybe a menù to assign a BFO default value, like BFO zero, will circumvent the issue. But, again, this will be space for firmware upgrading!

73 de IU3POA!

[N7SIX]

Hello everyone,

I would like to ask @phdlee if the link below with SI4732 additional part for K5 will work with your firmware? https://www.aliexpress.us/item/1005006603092025.html?gatewayAdapt=4itemAdapt&fbclid=IwAR0vdrz8DAsLToOhCzIvDAVzjXcHADi9kouPmmTMo2qH1z7ke8urbjgpCmM

73 Sean, N7SIX

[iu0azb]

I would confirm you ;) it works

[N7SIX]

Thank you!

[alboc2k]

I can confirm 3 successfully modded radios. Mine and 2 other OM, IW3GPO and IZ3ALE, same with "pre" BATCH PCB I designed. We all go for dedicated AMI port, with different solutions. Stay tuned ;-D

A info video:

https://www.youtube.com/watch?v=05nBVLC5yCo

73 de IU3POA!

[N7SIX]

I can confirm 3 successfully modded radios. Mine and 2 other OM, IW3GPO and IZ3ALE, same with "pre" BATCH PCB I designed. We all go for dedicated AMI port, with different solutions. Stay tuned ;-D

A info video:

https://www.youtube.com/watch?v=05nBVLC5yCo

73 de IU3POA!

Did you remove some parts from the original board?

[iu0azb]

Connecting the antenna input of si4732 to a dedicated output no ;) If you want to use a single antenna, follow the tips described on CEC website

[bubnikv]

There seems to be a new model of the extension board, which seems to connect the FM port to the original FM preamp, while connecting the HF port to the 2nd antenna. There seems to be a new HF preamp chip on the addon board.

https://vi.aliexpress.com/item/1005007196802850.html?ug_edm_item_id=1005007196802850&pdp_npi=4%40dis%21CZK%21CZK412.66%21CZK325.92%21%21%21%21%21%402141351617208402169365076d084d%2112000039770152008%21edm%21%21%21&edm_click_module=alg_product_3_8345504470&creative_img_ind=17&edm_log_data=edm-item-list-three-columns.store-product-log-link&tracelog=rowan&rowan_id1=aeug_edm_23869_1_en_US_2024-07-12&rowan_msg_id=bub*COWS_23869_%24aea334561def445d8a0647c8b84b6ffd&ck=in_edm_other&gatewayAdapt=glo2vnm

IMHO I don't think the preamp is needed for HF and it seems the HF input is heavily overloaded by the preamp. None of the application notes propose a preamp for HF. https://pdf1.alldatasheet.com/datasheet-pdf/view/792143/SILABS/AN400.html https://www.digikey.cn/Site/Global/Layouts/DownloadPdf.ashx?pdfUrl=5C850C92D37D4D12BD444A9A0FA3D79C

[jh4vaj]

I have built a PCB that splits the signal from the antenna into HF and FM broadcasts and inputs to AMI and FMI. I skipped the UV-K5 preamp and did not use it. I posted the details on my blog (written in Japanese).

https://www.jh4vaj.com/archives/44346