I like to upgrade Mossmann HackRF One card to protect MGA-81563 mosfet IC used on board on Rx and Tx side. There was one design by Clifford made by 2020 schematic , and GitHub Issue number #541 will explain more why MGA-81563 circuit burns often, also here is original HackRF schematic. I plan to made add on board on top of HackRF with 4-5 elements and connect this elements with wires on HackRF. That would be something like this



For Tx side of upgrade I need to insert this, which is just screenshoot of Clifford design in 2020 schematic link on page 2 and this is what I have right now, or original HackRF card screenshot from HackRf schematic link, page number 3.


I need to put on add on board everything between C64 and L13, MGA IC protects 2 SM1330 diode Bias Forwarded, I also need R39 and R40.

I don't know what is purpose of C172. Don't know if C172 is needed for protection MGA-81563, or it's needed for also upgraded bias, which is everything above C172 (I have L13, but new design have also L14), and I don't use bias at all, and not plan to upgrade bias side.

Question is do I need C172, so I need to cut off link on HackRF card between C63 and L13, or I just need to connect D12 diode on L13

 

I have a hackrf. Those are some critical dimension circuits. You can't just hack something in there on a aux board and expect similar circuit function to a on pcb revision.

Great hardware, it'd be a shame to break it.

HackRF One using GQRX on Linux

 

I have a hackrf. Those are some critical dimension circuits. You can't just hack something in there on a aux board and expect similar circuit function to a on pcb revision.

Great hardware, it'd be a shame to break it.

HackRF One using GQRX on Linux

I'm not doing this because like to try that, I need to change MGA-81563 IC circuit at least one per month, if Rx and Tx are doing fine job for you, sure DON'T DO IT, you can check it here, issue is that I'm using Tx intense and 14dB gain, that offer MGA IC is around 30-40% in degradation performance, sorry like to fix that.

 

I'm not doing this because like to try that, I need to change MGA-81563 IC circuit at least one per month, if Rx and Tx are doing fine job for you, sure DON'T DO IT, you can check it here, issue is that I'm using Tx intense and 14dB gain, that offer MGA IC is around 30-40% in degradation performance, sorry like to fix that.

I understand the reason the protection was added but you questioning why if X component is important IMO means you don't understand exactly what you are doing designing a add on board to the PCB.
IMO an external protection circuit connected to the RX connector would be more practical and replaceable in-case of protection device failure instead of hacking the PCB.
https://www.minicircuits.com/WebStore/dashboard.html?model=VLM-33W-2W-S+

 

Thanks for that, and you can confirm that limiter is working for you....

Although price would be around half, for the whole Chinese HackRF version with new elements implemented.

That would be blocker for Rx output connector, but from that issue #541, MGA can be fried also from USB connector, specially if you are using portapack extension, personally I didn't fried MGA IC, more 3.3 voltage converter, and inductor, just after USB connector

 

The H2 portapack extension looks pretty cool but I can see why it's causing problems with TX power amplification that could easily be illegal in most bands and locations without proper licensing.

 

The H2 portapack extension looks pretty cool but I can see why it's causing problems with TX power amplification that could easily be illegal in most bands and locations without proper licensing.

But Mossmann predicts that, so he put MGA-81653 in front of Tx and Rx side, users are actually sabotage by the board creator ;-) , besides don't have portapack, it's just example LiPo or USB adapter with high current will burn hackrf also. Actually this two diodes SM1330 bias forwarded protects whole board, comparing with limiter which protects only output SMA connector, besides you didn't replay, do you actually have limiter protecting hackrf