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#QMX #QDX #QDX-M output transformers (WTST and RWTST) documentation

#qmx #qdx #QDX-M

Hans Summers All Messages By This Member #109801 Hi all Many thanks to Ross EX0AA for his transformer designs, the 3:3 ratio (9V operation) WTST (Weird Twisted Sisters Transformer) and 3:2 ratio (12V operation) RWTST (Really Weird Twisted Sisters Transformer).? I have now uploaded documentation for both these designs and the original simple design, all in one document which is referenced from the QMX, QDX and QDX-M assembly manuals.? The original purpose of the designs was to solve the parasitic resonance problem that sometimes reduced output power on 10m band on the high-bands QDX. However the improved symmetry and tighter coupling of these transformers does improve performance (put power, efficiency, suppression of even harmonics) on all versions of QMX, QDX and QDX-M. Therefore the twisted wire transformers are now the recommended build for all these transceiver kits.? The transformer instructions are linked from each of the QMX, QDX and QDX-M pages. I removed the transformer instructions from the respective assembly manuals. So you will have to use the transformer document and choose the appropriate transformer (WTST for 9V, RWTST for 12V supply operation.? 73 Hans G0UPL
Cliff All Messages By This Member #109812 开云体育 Thank you Hans. After reading the doc I take it that the improvement for low band units is not significant enough to warrant replacing the original type of transformer, yes? 73, Cliff, AE5ZA toggle quoted message Show quoted text On Sep 12, 2023, at 12:34, Hans Summers <hans.summers@...> wrote: Hi all Many thanks to Ross EX0AA for his transformer designs, the 3:3 ratio (9V operation) WTST (Weird Twisted Sisters Transformer) and 3:2 ratio (12V operation) RWTST (Really Weird Twisted Sisters Transformer).? I have now uploaded documentation for both these designs and the original simple design, all in one document which is referenced from the QMX, QDX and QDX-M assembly manuals.? The original purpose of the designs was to solve the parasitic resonance problem that sometimes reduced output power on 10m band on the high-bands QDX. However the improved symmetry and tighter coupling of these transformers does improve performance (put power, efficiency, suppression of even harmonics) on all versions of QMX, QDX and QDX-M. Therefore the twisted wire transformers are now the recommended build for all these transceiver kits.? The transformer instructions are linked from each of the QMX, QDX and QDX-M pages. I removed the transformer instructions from the respective assembly manuals. So you will have to use the transformer document and choose the appropriate transformer (WTST for 9V, RWTST for 12V supply operation.? 73 Hans G0UPL
Roger Hill All Messages By This Member #109814 Minor typo. On page 5, Step 1. Currently says cut 25mm of wire...should be 25cm. Roger 8P6RX Get On 12 Sep 2023, at 15:11, Cliff <ae5zaham@...> wrote: toggle quoted message Show quoted text Thank you Hans. After reading the doc I take it that the improvement for low band units is not significant enough to warrant replacing the original type of transformer, yes? 73, Cliff, AE5ZA On Sep 12, 2023, at 12:34, Hans Summers <hans.summers@...> wrote: Hi all Many thanks to Ross EX0AA for his transformer designs, the 3:3 ratio (9V operation) WTST (Weird Twisted Sisters Transformer) and 3:2 ratio (12V operation) RWTST (Really Weird Twisted Sisters Transformer).? I have now uploaded documentation for both these designs and the original simple design, all in one document which is referenced from the QMX, QDX and QDX-M assembly manuals.? The original purpose of the designs was to solve the parasitic resonance problem that sometimes reduced output power on 10m band on the high-bands QDX. However the improved symmetry and tighter coupling of these transformers does improve performance (put power, efficiency, suppression of even harmonics) on all versions of QMX, QDX and QDX-M. Therefore the twisted wire transformers are now the recommended build for all these transceiver kits.? The transformer instructions are linked from each of the QMX, QDX and QDX-M pages. I removed the transformer instructions from the respective assembly manuals. So you will have to use the transformer document and choose the appropriate transformer (WTST for 9V, RWTST for 12V supply operation.? 73 Hans G0UPL
Roger Hill All Messages By This Member #109815 And step 14 on page 10, line 1: Scrap should be scrape! Roger Get On 12 Sep 2023, at 15:32, Roger Hill <rhill@...> wrote: toggle quoted message Show quoted text Minor typo. On page 5, Step 1. Currently says cut 25mm of wire...should be 25cm. Roger 8P6RX Get On 12 Sep 2023, at 15:11, Cliff <ae5zaham@...> wrote: Thank you Hans. After reading the doc I take it that the improvement for low band units is not significant enough to warrant replacing the original type of transformer, yes? 73, Cliff, AE5ZA On Sep 12, 2023, at 12:34, Hans Summers <hans.summers@...> wrote: Hi all Many thanks to Ross EX0AA for his transformer designs, the 3:3 ratio (9V operation) WTST (Weird Twisted Sisters Transformer) and 3:2 ratio (12V operation) RWTST (Really Weird Twisted Sisters Transformer).? I have now uploaded documentation for both these designs and the original simple design, all in one document which is referenced from the QMX, QDX and QDX-M assembly manuals.? The original purpose of the designs was to solve the parasitic resonance problem that sometimes reduced output power on 10m band on the high-bands QDX. However the improved symmetry and tighter coupling of these transformers does improve performance (put power, efficiency, suppression of even harmonics) on all versions of QMX, QDX and QDX-M. Therefore the twisted wire transformers are now the recommended build for all these transceiver kits.? The transformer instructions are linked from each of the QMX, QDX and QDX-M pages. I removed the transformer instructions from the respective assembly manuals. So you will have to use the transformer document and choose the appropriate transformer (WTST for 9V, RWTST for 12V supply operation.? 73 Hans G0UPL
Rick NF6G All Messages By This Member #109817 Step 14, page 10, right-band side should be right-hand side.
Hans Summers All Messages By This Member #109829 Hello Cliff ? After reading the doc I take it that the improvement for low band units is not significant enough to warrant replacing the original type of transformer, yes? Yes, correct; I would recommend any constructors building QDX, QDX-M or QMX to use the twisted transformers; but if what you have already works fine, then no need to change it. Always remember, "if it ain't broke don't fix it". It's my common observation that a lot of people spend a lot of time and energy fixing problems they don't actually have. Thanks too to all the other respondents on this post, I have now corrected the typos you identified in the new transformer manual.? ? 73 Hans G0UPL
Walt (KK4DF) All Messages By This Member #109834 Hans, Version 1.00a of the document has WSTS instead of WTST on pages 1 and 11. Walt - KK4DF?
Chris KB1NLW All Messages By This Member #109847 Thanks Hans: I carefully measured my QDX with a scope and saw only a ~20% reduction at 10m.? So for now I'll hold off the RWTAT. I look forward to the QMX HB.? I assume your carefully designing and testing the BPF.
Hans Summers All Messages By This Member #109881 Thanks Walt I have corrected the typo on pages 1 and 11. 73 Hans G0UPL toggle quoted message Show quoted text On Wed, Sep 13, 2023 at 12:24?PM Walt (KK4DF) <wewilsonjr@...> wrote: Hans, Version 1.00a of the document has WSTS instead of WTST on pages 1 and 11. Walt - KK4DF?
Jon Pike All Messages By This Member #110464 On Wed, Sep 13, 2023 at 12:37 AM, Hans Summers wrote: Hello Cliff ? After reading the doc I take it that the improvement for low band units is not significant enough to warrant replacing the original type of transformer, yes? ? Yes, correct; I would recommend any constructors building QDX, QDX-M or QMX to use the twisted transformers; but if what you have already works fine, then no need to change it. Always remember, "if it ain't broke don't fix it". It's my common observation that a lot of people spend a lot of time and energy fixing problems they don't actually have. ? ? Hi Hans...?? haven't been by the site for a while,? just noticed the TX transformer doc the other day.?? Uh, I do fit into that description,? so, debating on making the change on my low band Rev 3.5....? but might do it anyway.?? A thought I had,? might there be a similar performance improvement in the T2 RX trifilar transformer?? I've had decent but not stellar RX performance on the internal test, though it dosen't seem to diminish my real world performance much.? Mine might not be the most consistently wound/twisted one, and I've wondered if rewinding T2 might improve the RX side with better balance?? What do you think?
Hans Summers All Messages By This Member #110465 Hello Jon Imbalance in the trifilar due to messy winding is one of the factors that can affect image rejection. But there are also others, component tolerances is an important one. Generally the biggest factor is amplitude imbalance and this is something which could be corrected in firmware, it's another thing on my ToDo list :-/ 73 Hans G0UPL toggle quoted message Show quoted text On Thu, Sep 21, 2023 at 9:01?AM Jon Pike <jhpike@...> wrote: On Wed, Sep 13, 2023 at 12:37 AM, Hans Summers wrote: Hello Cliff ? After reading the doc I take it that the improvement for low band units is not significant enough to warrant replacing the original type of transformer, yes? ? Yes, correct; I would recommend any constructors building QDX, QDX-M or QMX to use the twisted transformers; but if what you have already works fine, then no need to change it. Always remember, "if it ain't broke don't fix it". It's my common observation that a lot of people spend a lot of time and energy fixing problems they don't actually have. ? ? Hi Hans...?? haven't been by the site for a while,? just noticed the TX transformer doc the other day.?? Uh, I do fit into that description,? so, debating on making the change on my low band Rev 3.5....? but might do it anyway.?? A thought I had,? might there be a similar performance improvement in the T2 RX trifilar transformer?? I've had decent but not stellar RX performance on the internal test, though it dosen't seem to diminish my real world performance much.? Mine might not be the most consistently wound/twisted one, and I've wondered if rewinding T2 might improve the RX side with better balance?? What do you think?
Jon Pike All Messages By This Member #110585 Ah...??? Well, I vaguely remember having less wire left over for T2 than expected, and think I had to unwind some of the twistings, just to end up with enough length to poke thru the holes during the mounting. It didn't turn out as neat as I would have liked...?? Do you think it would be possible to wind too tight/too many twists? (WTST style?) Or is it better to aim at the suggested 60 or so twists,? but just focus on even and consistent over the length? On the part tolerances...? do you mean the 33nF's (C39-43?),? or do you mean the parts around the op-amp ADC front end?? I think I can imagine (pun there, see it?) some kind of test to take values and cancel out the differences, for a really balanced detector. Awesome!
Glenn S All Messages By This Member #111073 I replaced the standard transformer with the WTST today to see how it compares on the 80-60-40-30-20m build. There was a worthwhile increase in power on all bands and maybe a smidge more efficiency.? Tested on 9.5V as I'm running the QMX on 2 x LiFePO4 cells (10.8 Max, 9.9 Nominal). ? ? ? ? ? Standard? ? ? ? WTST 80m? ? ?3.0W? ? ? ? ? ? ?3.25W 60m? ? ?4.0W? ? ? ? ? ? ?4.2W 40m? ? ?3.7W? ? ? ? ? ? ?4.0W 30m? ? ?4.0W? ? ? ? ? ? ?4.5W 20m? ? ?3.7W? ? ? ? ? ? ?4.3W Cheers,? Glenn VK3YY.

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