Correct, there is only one "ideal" matching point. The problem is finding it. The article I referenced was for an L-type tuner. The article also had a design of a search algorithm which is worth, at least, looking at. It looks pretty well thought out. Unfortunately I can't determine if the existing algorithm is well thought out as it is not documented.

73,
Chris, K9EQ

I converted my ATU100 firmware 3.2 to use Tom Court's latest algorithm that is available from??see tune2.c and tried it on my usually problematic doublet antenna.? It works a treat on my usual bands (40/60/80) and achieves a sub 1.25 tune in just a few seconds.? Certainly the best algorithm I have tried.

I understand this is work in progress and there is potentially better to come.

This is science ()?being applied by a good software engineer, thanks Tom Court.

In my view David N7DDC did a good job with the hardware design and this software will take it to the next stage!

73's
David M0TGC

So here is an update.
HW changes:
Used a 74AC14 as the front end, with a 74HC393 after. ?Tried various divides and div 4 works well (and needs least time).
I've move the SW FET input from pin 11 to one of the TX lines (as I don't use them).
cut the trace on the top of the board and hardwired the 393 output to it.
the new wire was easy to do underneath.

SW changes:
put #ifdef around the Tx PIN code.
moved the cap_sw to one of the TX pins
I changed the display type to a #define, the compiler then removes the code for the other displays.
I added some basic code that checks the freq, if there are settings (or +/- a slot) then try them, if they are good use them, otherwise search. ?If we find a good solution save the settings.

Wrote a debug loop that displays the freq.
Put a signal generator on the input and it maxes out at 17.5MHz.

That's as far as I've got today , need to dig out the proper scope (100MHz) instead of the USB one (24MHz sample rate).

I was a little surprised when you put the code built code out there to try. The algorithm was really just a first iteration at it was only about 20% improved over the existing algorith. I've got a much improved algorithm (with regards to the hill climbing) currently checked in to github, its more at 70%s. I'm still working on a better method for locating the hills to start climbing (the initial 73 points), until thats done I'm not sure if it will be completely practical.

There is a bug somewhere in the 'battleship' mode that I can't quite pin down, so I'm not sure if I'm getting the best values to begin with. Despite that, in emulation it does quite well. But I still do want to get rid of a fixed table for starting points anyways.

Was the report of the slower tuning something on this board or a private communication? I did see your reference to getting stuck tuning.

Regarding the porting issue due to SW = sw being misinterpreted. I'm wondering if there are other porting issues with the target compiler if the actual performance doesn't seem to match the emulated performance.

Ok I had to do some adjustment and I now have the power reading spot on…but the SWR value is off. I’m going to go ahead and replace the diodes since I have them and keep tinkering for a bit and check back in a few days.?

The display is now functional too! Thanks Immo for the suggestion on the EPPROM and changing the offsets to zero.?

I appreciate everyone who is weighing in and helping me out.?

开云体育

Yes Elijah, it is correct, as described in the manual.

Thanks for the input Markus. I’m confused with the input into EPPROM. If I’m at 1:20, the input should be 20 correct in cell 31?

Hi, Tom
Your algorithm has the disadvantage of unconditional 73 point checks. This causes SWR goes to very large value and a TRX reduces a power to almost zero.
If you wanna build really practically working algorithm you must resolve this problem.
Only one tester tried your algorithm and in the most cases it works slower than original one.
I see very little interest in new algorithms. I think the old one works well and users just don’t need it.

Hi.
In a separate topic, I raised the issue of the correct adjustment of RV1 and RV2 on the PCB, but no one has answered yet, and I don't expect anyone to answer either... anyway, I was just asking out of curiosity.

In the original project (ATU100), the author used a fixed divider of 1/3, and the only adjustment element is (depending on the desired maximum power) set by the tandem ratio, a value that is also declared in the corresponding eeprom cell.

In my tuner I used a fixed divider (68K/34K), tandem with a ratio of 1:32. I configured the EEPROM cells according to the manual on github... and that was it!

Success!

hi Elijah,

for correcting the display, look for the cells 7 and 8 on EEPROM.?
Try setting both to 0 (zero)... that may solve this issue.

73, Immo

can nobody id what type of coupler is in the pics i posted?,it is from an old avair 1000 swr meter that had an open meter movement,the coupler is from 1.8-150 megs,the uhf is a seperate item.

Hello Geoff and others. I successfully erased the protected chip and uploaded the new firmware with some corrections. It took me a while and numerous times of trial and error…but it at least turns on. I’m still experiencing an issue with the SWR/power meter being way off even though I updated the hex code EPROM with the turns (20 in my case) for the bridge. On top of that, my display is depicting numbers to the left and items on the bottom that we’re not there before. (See attached photos) How should I remedy both the bridge indication and the display? I’m not frustrated yet, but this is challenging ?.?

power at 10 watts

Power indication at 10 watts

Display woes

?

I've developed an extensive test framework for comparing both how fast and how well algorithms perform using a simulated matching circuit. I've commented the code for my newest algorithm to some extent. It's actually fairly straightforward except for the derivations of the WAGs (wild a$$ guesses). You can see it and the framework at?

The algorithm in the extensive article from k6jca you mentioned is not much different than my last iteration (the one posted on the group previously).

Hi Singleshare,

I've just joined this group and your message solved my problem with an ATU-130 (similar to the ATU-100) that wasn't tuning.

However, in my case it was operator error. I had plugged the antenna into the "IN" socket and the radio into the "ANT" socket!

I now works as I swapped the coaxial cables over...
--
Dave (G0DJA)

Hi, Chris, I don't think the Г shaped matching has multiple minimum SWR combinations. I think there is only one in ideal condition.

A word of caution. One can find the fastest match or one can find the best match. I suspect the two are not the same. It is possible for a tuner to have multiple combinations of L and C where a low SWR is produced. However, only one of these solutions is likely to be the most efficient. K6JCA did a lot of work creating his own 500 watt tuner. In Part 9 of his 10-part article he discusses finding the best return loss (lowest SWR) while obtaining a reasonably efficient match. His entire article is a trove of information about how an antenna tuner should be designed. One part I found particularly interesting was the section on inductor and capacitor selection.



Fortunately he defines his search algorithm in detail. One of my (many) complaints about "free" software is that it is poorly documented. I'm not complaining, but it is unfortunate that the ATU firmware archive does not include documentation on how it works. A flow chart would be very useful in order to quickly see how the algorithm works. It's simply not possible to compare dozens of pages of programming code to easily see how two different systems work!

Perhaps, someday, I'll sit down and struggle through the C code and convert it to an easy-to-understand specification.

My main point is that the efficiency of the final match needs to be considered, otherwise we are probably best sticking with what seems to work reasonably well. One last point. Poor efficency means that the power is going somewhere, just not into the antenna. That usually means higher voltages and currents within the tuner which then dissipates energy in the form of hot components.

73,
Chris, K9EQ

Thanks David
Regards

Yes , the Chinese clone is a little bit better then original , so 3.5.

Dear all,
I was thinking to buy a pickit3 and looking for it i've seen the pickit 3.5.
I have not find info about it and my doubt is, Is the pickit3.5 compatible with the AT100 as the pickit3?
Thks from Barcelona