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1
RF, Microwave, Ham Radio / Re: vacume caps
« Last post by coppercone2 on Today at 12:26:08 pm »
but we can still answer the question in general because of the first post being general and it actually makes the thread better if the more specific question has been answered because its more information
The problem is that a specific answer may be irrelevant to the original poster’s query, in this case the irrelevant answer was magnetic loops.

Many n00b’s have been lambasted for not providing enough detail in their questions. The Beginners thread description even instructs beginners to provide as much detail as they can, in order to assist contributors to give an accurate and relevant response.

a thread where people just post to a general topic can be more interesting and long lived then a specific solution to a engineering problem.
2
Test Equipment / Re: Hacking the Rigol DHO800/900 Scope
« Last post by AndyBig on Today at 12:25:28 pm »
At least it should be possible to replace certain multipliers that I don't need (like 50000x) with those I do need by editing the .so directly.

But if we find a way to recompile it, then it'll open a whole lot of new possibilities. If not from C code, then at least it should be possible to recompile it from assembler.
No, it’s almost impossible to recompile the library :( But you can change existing values in it. If you really bother, I think you can even enter a user-specified divisor value, but this is a lot of work both in .so and in .app .
3
Test Equipment / Re: Hacking the Rigol DHO800/900 Scope
« Last post by shapirus on Today at 12:24:06 pm »
At least it should be possible to replace certain multipliers that I don't need (like 50000x) with those I do need by editing the .so directly.

But if we find a way to recompile it, then it'll open a whole lot of new possibilities. If not from C code, then at least it should be possible to recompile it from assembler.

p.s. what did you use for decompilation? Ghidra gave me only this:

Code: [Select]
void _ZN12CApiVertical24ApiChannel_SetProbeRatioEj(void)

{
  _ZN12CApiVertical24ApiChannel_SetProbeRatioEj();
  return;
}

either it couldn't do its job, or I didn't use it the right way.
4
Test Equipment / Re: Hacking the Rigol DHO800/900 Scope
« Last post by AndyBig on Today at 12:18:29 pm »
To set or save the value of the probe divider, it is not the value of the divider that is sent to .so, but its serial number from 0 (corresponds to 0.0001) to 30 (corresponds to 50000.0).
I figured that much too, but haven't yet found where those numbers are accepted and processed in the .so. There are some functions having the "ProbeRatio" substring in their names, but ghidra did not disassemble their bodies -- in the .c file it produced they seem to be calling themselves, which is weird. Maybe the actual code should be inside them, maybe not.

p.s. even if we figure that out, then recompiling the .so is going to be a much more difficult job than the same with .apk, and I'm not sure if even possible.
The conversion of the divisor from the index to the real value occurs in libscope-auklet.so in the function CApiVertical::ApiChannel_SetProbeRatio (see screenshot). The index value is taken from address 0xd203f8, where there is an array of 31 16-byte values (see screenshot). Each value represents 8 bytes of real value and 8 bytes of decimal power. For example, the first index contains the 16-byte value 0x0100000000000000FCFFFFFF00000000, which means 1 (0100000000000000) multiplied by 10 to the power of -4 (FCFFFFFF00000000).
The real address of this array in the libscope-auklet.so file is 0x00C1F3F8 (see screenshot).

5
RF, Microwave, Ham Radio / Re: vacume caps
« Last post by p.larner on Today at 12:16:25 pm »
what bw do you get with your loop on 80m markus?,wide enough for ssb or just data?.
6
Letw get this straight. You need to re patch after each update or you lose the options you added?
If so , them we should expect that the hack will be fixed at some point.
Finally I guess you can just return the scope to it's older self with the back and re hack it, keeping it in an older FW version.
Am I correct in my assumption?

Here's my 2 cents

1. Yes absolutely you can revert the scope to and older FW Version

2. Re the patch after every update,   Right .... but how often to we update them ?
I've got a DS2000A , i think i've had it for 10 Years now,  Did the original update and unlocked all the options, Now, there is a current newer
version, do i need it... No not really

So on one hand it may be the case that we may need to, On the other (at least speaking for myself) who cares.
and another point, if we are going to talk about inconvenience....   THIS IS WHAT WE DO , We put effort into out scopes so we can have
these unlocked options and if that means say every 3 or 4 years having to do it again, why is that an issue.  and even if we decide now
that it has to be done, things may change in a few years anyway and it may or may not need it.

for me, i don't think we need to but even if we do, i don't see the big deal with it anyway.
7
Keep the ship for collateral - some 1851 law which was cited by the Titanic’s owner in a Supreme Court case 1912, could limit the payout. Titanic law could help ship owner limit liability in Baltimore bridge collapse

Estimates are $2B to repair/replace the bridge, $0.1B to free the ship and clean up the mess. Biden is talking like the Feds will give the money, but I have to ask why the US taxpayer is ultimately on the hook, as well as the many years of cranked up toll pricing we know will result. OUCH.

The article makes it sound a bit like it is some loophole in an old, forgotten law. But in fact the principle of limited liability has been a central element of maritime codes internationally for centuries and it comes up in almost all major shipping accidents.

Now, many people do think that this doesn't really make sense anymore in a world where LLCs and huge insurance companies exist and shipping isn't nearly as dangerous as it used to be. But any attempt to change this unilaterally might prove hard to enforce. E.g. the owner of the MV Dali is based in Singapore which is a member of the International Convention on Limitation of Liability for Maritime Claims.
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Test Equipment / Re: Hacking the Rigol DHO800/900 Scope
« Last post by shapirus on Today at 12:10:26 pm »
To set or save the value of the probe divider, it is not the value of the divider that is sent to .so, but its serial number from 0 (corresponds to 0.0001) to 30 (corresponds to 50000.0).
I figured that much too, but haven't yet found where those numbers are accepted and processed in the .so. There are some functions having the "ProbeRatio" substring in their names, but ghidra did not disassemble their bodies -- in the .c file it produced they seem to be calling themselves, which is weird. Maybe the actual code should be inside them, maybe not.

p.s. even if we figure that out, then recompiling the .so is going to be a much more difficult job than the same with .apk, and I'm not sure if even possible.
9
EEVblog Specific / Re: WFT TV
« Last post by golden_labels on Today at 11:55:04 am »
Sounds perfect for people moving their TVs three times a day. /s

Based on the advertisement from CNET(1), it has a pump. But I guess it’s used only for attachment. In the same video we can see the suction cups are about 10×40 cm each. They should be able to hold a 10 kg TV passively.

They have a nice privacy policy, from which they didn’t even remove template messages and comments. ;)


(1) https://www.youtube.com/embed/chVyHEADcms
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Beginners / Re: UHF VHF tv antenna design
« Last post by wasedadoc on Today at 11:53:54 am »
A Yagi is a special case of a log periodic array.
Not really true.  A Yagi has only one driven element whereas all elements of a log periodic are driven.
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