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Re: coding
Jack Purdum
Tom: I started with C in the late 1970's and it's remained my favorite language ever since. You can actually do a lot of "mental optimization" with beginning students if you explain the differences to them. The RDC code I mentioned earlier was a 31-level cascading if-else statement block, one for each day of the month. On average, there would be 15 false tests on every pass through the loop. This was for banks with millions of customers and some of those days involved looking at each one of those customers' transactions for the month. Because a switch/case generates a jump table instead, meaning just one compare regardless of the day, that one change pared off almost an hour of runtime. Today's compilers are smart enough they might generate the jump table anyway! I also know that students remember "off-the-wall" explanations best. I use prostitutes to explain the OOP concept of encapsulation. When I was teaching econ at Butler, I used to tell my freshmen students I could end poverty overnight. (Way back then, poverty was $9600/yr for a family of four.) When they asked how, I told them you get all the people making $9600 or less, line them up, and shoot them! After their pie-plate eyes recovered from the shock, I asked them how long it would take for the person making $9601 to start bitching about being "poor". We went on to have a good discussion of income inequality, incentives, how economic growth raises income even if your slice of the pie stays the same, etc. The more wild, the better it is remembered. BTW, if you want to see the assembler code for your project, go to File --> Preferences and turn on the verbose mode for compilation. There will be a lot of lines generated, but near the end will be something like: A bunch of stuff...C:\Users\User\AppData\Local\Temp\arduino_build_692458/JackAlV050.ino.elf with "elf" at the end. Copy the path name (in yellow above) into Windows Explorer and look for a file that ends in "lst". That will allow you to see the assembly code for the program by load that file into any text editor. Note: You can only do this using the compile icon. If you do compile/upload, you won't find it because these are treated as temporary files and are erased after the upload. Also, you'll want to turn off the verbose mode as it does slow the compile down a tad. Jack, W8TEE
On Tuesday, August 21, 2018, 11:30:15 PM EDT, Tom, wb6b <wb6b@...> wrote:
Yes that is true, if I didn't originally learn C on non-optimizing compilers for simple machines and check the "real" code, assembly, to see if C was dong what was expected, I think my understanding of programming, CPU chips and hardware would have been hampered and shrouded in mystery as to what the code is actually doing.? So helping new programmers getting starting by coding like there are no optimizers, so it is possible to visualize the relationship between your code and what the program does (without added mystery) is a good idea. Shutting off the optimization and looking at the assembly code would be more instructive than looking at optimized code. Although looking at and understanding both, at a later point, is good.? Now days with big caches it can be really interesting to write optimized code, because you start playing games with the code so it will stay and not get flushed out of the caches. These little processors really get back to basics, that is refreshing. Tom, wb6b |
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Re: boosting the power on 28 MHz
#ubitx
Timothy Fidler
Kees Talen builds and sells an amp using Mitsi mosfets? that goes 80 to 6 m.? He uses RD16HHF1 . not the VHF version . he is very conservative in design.
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http://www.qsl.net/k5bcq/Kits/Kits.html claims 16W out SSB with no artifacts?on the Spectro box? (20W nominal ) it maintains this Power all the way up to and inclu 52 Mhz. This is because he is using a Cu tubular core type TFR in type 61 material . The input Trafo does not matter as there is power to burn. He mentioned this to? me in some emails.? He also tried the old CT Primary and gave up - it seems there was too much variation from one coax ferrite to the next.? So he want over to the phasing choke method for power in. So at 28Mhz what will be your limit after this change out is the Ferrites, specifically the OPT . Type? 43? is Very? bad at this frequency possibly 3/4 of the impedance is resistive loss .? There is data on this versus type 61 premium material? on the Antennas part of the site and I hve a bit more .? ?The thing about type 43 is it is cheap and there are several equivalents to it made in Europe.? Type 61 is the ONLY material to use above about 8 Mhz.? Because the Ue of 61 is? 125 versus the? 800 nominal for type 43 , if you do? a change out, you will need to change the transformer out to say two x? size 80 stacked, if they will fit so you do not lose too much in shunting on the lower bands? (NEEDS to be calculated not guessed) Ie you would need to? keep the primary inductance up to say min of 0.8 x what it is at moment or you compromise the design on 3 Mhz. If you don't change the ferrites and windings then you could have very capable set of Mosfets but still not much improvement.?? Sorry to be a bringer of bad news.? Obviously the Trafo of the driver set is also eating power so if you are up for surgery look there too.? A recent poster made a comment re change out of drivers to 2n3866 . which is? hard beast to find.? 2n3053 would be as good at this frequency.? I don't know if he changed out all four or just two and threw the other sissy drivers away.? If you have big drivers with press on heatsinks on them and not too much drive to their bases, you may be able to go for gold and short out the emitter ballasting resistors which are costing you drive power.? I have not mentioned Balun transformers on purpose.? If you did all those changes I would guess you would get easily 12 W out even at 28 Mhz. Also the core temperature of the Mosfets will be lower. By the sound of things.. power is severely compromised on high bands.? Flowers said as much when he did the 20 m coversion. He was getting only 2 W out he said before the RD15HH... then 6W after.? Given the kludging of the connections you are going to have to do I would not risk the higher gain Vhf Version. Flowers used it only as he found it easier to buy.? ? Timothy E. Fidler : Engineer BE Mech(1) Auckland , NDT specialist AINDT UT /RT3 , MT2 CB #2885,?
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Re: boosting the power on 28 MHz
#ubitx
Would there be a clear advantage to replace them? Il 21/ago/2018 23:09, "Timothy Fidler" <engstr@...> ha scritto: Simple answere is NO .? But there are advantages as per below. |
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Re: Loud sound on first power-up
#ubitx
Yes, I did the same, look at the potentiometer connections that might be reversed. I ended up frying the TDA. Il 22/ago/2018 09:45, "Raj vu2zap" <rajendrakumargg@...> ha scritto: m, |
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Re: Loud sound on first power-up
#ubitx
m,
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Check your wiring, probably in the audio connections. Check the stock volume control for proper value etc. r At 22-08-18, you wrote:
I'm at last got my uBitx wired up: slightly older (2017 date) board, in out-of-the-box condition with no mods or software updates. Based solely on reading, I believe I might have the TDA2822 problem, but this seems different. |
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Loud sound on first power-up
#ubitx
I'm at last got my uBitx wired up: slightly older (2017 date) board, in out-of-the-box condition with no mods or software updates. Based solely on reading, I believe I might have the TDA2822 problem, but this seems different.
When I turn the power switch on, there's a constant, loud, harsh buzzing noise from the speaker or headphones, maybe around 10 or 15 Hz and wavering in frequency. It doesn't change volume when I adjust the volume control, though at the top of the range the buzzing gets higher pitched and sounds more like maybe water splashing. Anyone run into this? Where should I look for trouble? Is there a troubleshooting guide I've overlooked? 73, -m |
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Re: coding
Yes that is true, if I didn't originally learn C on non-optimizing compilers for simple machines and check the "real" code, assembly, to see if C was dong what was expected, I think my understanding of programming, CPU chips and hardware would have been hampered and shrouded in mystery as to what the code is actually doing.?
So helping new programmers getting starting by coding like there are no optimizers, so it is possible to visualize the relationship between your code and what the program does (without added mystery) is a good idea. Shutting off the optimization and looking at the assembly code would be more instructive than looking at optimized code. Although looking at and understanding both, at a later point, is good.? Now days with big caches it can be really interesting to write optimized code, because you start playing games with the code so it will stay and not get flushed out of the caches. These little processors really get back to basics, that is refreshing. Tom, wb6b |
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Re: coding
Jack Purdum
Hi Tom: I did look at the assembler output for a similar thing over a year ago and the compiler did make the optimization anyway. I'd be surprised if the GCC didn't make the change you're talking about. Still, there are a lot of new programmers coming on line and I think it's good to explain why one way of coding might be better than another. It's almost always better to perform the optimization between one's ears that rely on a compiler that may, or may not, perform the optimization. Even if the compiler didn't do the optimization, there's nothing wrong with the code. In other situations, however, coders make mistakes that lead to a teaching moment. One of the things I do in my book is show code that works, but then explain why it's RDC (i.e., Really Dumb Code). Once while I was on a consulting job, I came across some RDC that had been working in their banking software for years. I explained to the group why it was RDC and how it could easily be fixed. I was fired the next day because that code was written by the person who hired me. Over the years, I've had a lot of my own RDC code slip past my eyes. Sometimes I do catch RDC and think I've written a good solution, only to discover later on the solution was actually SDC (i.e., Sorta Dumb Code). There are people here who can code rings around me, and I actually like that. It gives me a chance to learn more. But the really great thing is that, other than a trivial problem, every programmer will devise their own solution. The overriding goal, however, is for the code to be correct, easily maintained, and not fragile. However one does that is an individual decision with multiple "right" answers. Jack, W8TEE
On Tuesday, August 21, 2018, 6:45:08 PM EDT, Tom, wb6b <wb6b@...> wrote:
So to elaborate on my previous really short reply. I really like the macro, it handles the hardcoding the number of elements issue well. For the definition inside the loop. I may be trusting the optimizer too much, the definition outside the loop is technically more correct. Out of curiosity I'll see if I can get an assembly output to look at, as with these tiny processors that type of code checking is still of value. In programming teams, as optimizers get better, the holy wars have started to move from coding style vs resulting assembly code to each individual programmer's perception of what must be easiest to read for them must therefore apply to everyone else. So, may have been beat-up in one of those wars.? Readability and coding is a manner that is consistent with the style of the team are good things, though.? Tom, wb6b |
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Re: Nextion 3.2 for CEC 1.097
#ubitx
I've cleaned up a few things on various screens.? The same download links above should now download the updated versions.
Darren |
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Re: Wow... 15 volts in and a bunch out..
Timothy Fidler
For 15.5 nSeconds read 16.5 nSeconds in the input capacitance calc of last post. TF.? Obvious kludge? Simple untuned emitter follower stages in class A will also give the effect of a coupling transformer to get the gate of a mosfet,? but at loss of stage efficiency.
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Re: Wow... 15 volts in and a bunch out..
Timothy Fidler
C'mon Jerry I think you are being a bit harsh.? I stated explicitly that the NN1G design was class C but it introduced? class of chips that people have been dismissive of.??
Let's have a look at what it can do with say an RDHH06 mosfet (ok 5 dollars from "Cecil the parts place" , but you don't get much in quality RF for that price (unless a lucky surplus buy). 50m**A out at +- 5V peak (say 12V supply which means chip? is running well within spec.) that means 0.125W based on RMS performance.? it also means chip is running at nominal 100Z out. ** It still works if you used the minimum guaranteed mA drive figure.? ? ? is a place to find the Dsheet. On page 6 of said DS we find smith chart and also an Amp perform. example Caveat .. it will be for class C . Everyone likes to make the part look better than it is .? Z in Real component 65R. Nice. as? a match. But it WILL drop when bias applied to move the device to class A? so a 4:1 Z drop bifilar transformer will have to be considered and obviously capacitive blocking at the LT device is still required a it is not being run on two rail supply. What about input capacitance of the MOSFET at frequency.? ?? Back calc from -150j Z given at 30 Mhz on the datasheet. We get 35pF plus or minus. The time const of the (Zout of the LT plus the RDHH)? x the 35 pF is? 5.8 E -9 s (but that is likely to be high side given that bias will be applied) . The Period for a 30Mhz wave is 33 E-9 s.? The Half period is what we need for comparison;? that is 15.5 nano Seconds.? We are well under that , we would like be say 4x? under but Life is Hard for the Poor Man.? The RDHH06 will then drive a Trifilar transformer 1:2 turns ratio. The RDHH is rated at 16 plus dB power gain ; that will be at class C with no transformer loss.? Say 12 dB in class A with output Transfor losses factored in. That is 15.8 x . Say worst case input we get 80mW out of the LT driven into the RD? , that is 1.26W or so out of the driver transformer to the IRFs .? There are no wild assumptions in there. Like anything in the RF fix line? A. it has got to fit? and B is is going to cost a lot to re-engineer.? the MaxCPA device I indicated as a possible subs. is just under $6USD ex Futurlec.com. The RDHH06F1 is about $5 in one off qty from place indicated above. you then have to get the magnetics and passives and make up a drop in PCB - possibly side mounted - whichever way you look at it , it will not be cheap C/With? initial price of the board.? If you think video chip drivers are rubbish , have a look at -? (obviously with EBay? -? I cannot make any undertakings re Link Rot. ? This uses the OPA2674 I indicated earlier as per post from Glen to me. It looks like a high quality build. Note how this chip costs you two off RF transformers before you get to the base (gate) of the PAs. regards - TEF |
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Re: #ubitx Complete shopping list for the ubix
#ubitx
There are other displays available: ?2.8 inch ILI9341 based touch screen display which is widely available on Amazon and eBay rOn On August 21, 2018 at 5:48 PM Bo Barry <bobarr@...> wrote: |
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Re: QRP SWR meter recommendation?
#ubitx
So to elaborate on my previous really short reply. I really like the macro, it handles the hardcoding the number of elements issue well.
For the definition inside the loop. I may be trusting the optimizer too much, the definition outside the loop is technically more correct. Out of curiosity I'll see if I can get an assembly output to look at, as with these tiny processors that type of code checking is still of value. In programming teams, as optimizers get better, the holy wars have started to move from coding style vs resulting assembly code to each individual programmer's perception of what must be easiest to read for them must therefore apply to everyone else. So, may have been beat-up in one of those wars.? Readability and coding is a manner that is consistent with the style of the team are good things, though.? Tom, wb6b |
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Hi,
A team of french operators kindly translated the installation and user instructions for the Raduino sketch for BitX40. I've included them in the Raduino repository on Github: Many thanks to Jacques F1APY,? Gilles F1BFU and Laurent F4CZI ! I believe your contribution will be of great help to other francophone builders. 73 Allard PE1NWL |
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Re: Wow... 15 volts in and a bunch out..
Hi Allison,
It was not clear in my post that I was not expecting the increased voltage to fix the harmonics and replace the needed fixes to output filters and such, but only to help with the drive to the finals issues and leaving some headroom before drive levels lead to additional harmonics from overdrive. And possibility more room for flattening the gain curve over frequency.? When a new board comes out I'll buy one. But, for our existing ones finding a minimal number of changes to improve the filters (external filters, add-on relays, etc), possibility just not using the bands where the mixer product is too close to the TX frequency to be easily filtered (won't really miss those bands), will still result in a transceiver I'd be happy to use for the price I paid. Let the more elegant fixes be applied to new productions boards and folks that want to make more the extensive mods to their transceivers.? Tom, wb6b |
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#ubitx Complete shopping list for the ubix
#ubitx
Bo Barry
Needing help from all!
Attached as a .PDF and LibreOffice Spreadsheet. Please provide input!! Goal is to make it into a club project, simplified as much as possible. Thanks, Bo W4GHV since '54 |
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Re: Wow... 15 volts in and a bunch out..
Yup, I skipped 17m.
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Also 30m and 60m. Those smaller WARC bands are supported, go for it! Jerry On Tue, Aug 21, 2018 at 02:43 PM, Bill Cromwell wrote: I think you omitted 17 meters in that lineup. I am using external filters for CW on those bands and keeping it under 10 watts. |
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Re: New Group Specifically for "Homebrew Test Equipment"
Hi Terry,
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The new group has already formed. If you haven't already signed on it's on grups.io. Login and search for HBTE. 73, Bill KU8H On 08/21/2018 01:14 PM, Terry Morris wrote:
My 2-cents worth, homebrewtestequipment, homebrew test equipment, --
bark less - wag more |
Raj vu2zap
Darren VE3XLT
Allard PE1NWL
Michael Monteith
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