Date
1 - 20 of 26
Toroid values #toroid
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Where is this chart of toroid values that Hans put together?
I'd like to get a look at it.
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Alan G4ZFQ
On 28/06/2022 06:39, kf7rcm via groups.io wrote:
Where is this chart of toroid values that Hans put together?Referring to what QRPLabs model? 73 Alan G4ZFQ
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QCX+ 20 and 40 meters.
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40 meters because that is the radio I am dealing with right now, 20 meters because I have one coming and need the information before I build it.
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Wayne, those values are in the charts in the sections of the instruction manual that deal with winding the toroids. So you'll have the needed info when you get to that stage of construction of the new one. And you can refer there for the info on the existing one. Hope that helps. Ron
40 meters because that is the radio I am dealing with right now, 20 meters because I have one coming and need the information before I build it.
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Evan Hand
The build manual contains the toroid material, number of turns, and corresponding inductance. For example, L2 is on page 72 of the rev1_04 of the manual. L1 and L3 are on page 73 of the manual. The others are on other pages (L4 on page 70).
You can always go to: https://toroids.info/ And look up the material and then input the number of turns to get the inductance value. If you want the inductance values for the individual sections on T1, you will need to do this for each section. 73 Evan AC9TU
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rentwist@...
Hi Evan,
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I am here to tell you from first hand experience, the values given by that calculator are way off, The real inductance comes out considerably higher. The only good way to know the inductance of a wound toroid is to measure it with a VNA. 73, Robert, WA2T
On Tue, Jun 28, 2022 at 03:41 PM, Evan Hand wrote: You can always go to:
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Yes they are and it does.
I should call it a day earlier than working on it until 01:00 and asking obvious questions. I appreciate the response, Wayne/KF7RCM.
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Evan Hand
Hi Robert,
I guess that we will need to disagree to some extent. I agree that the value can differ depending on how it is wound, including spacing. If you check the charts from Hans, the values mostly agree, at least within a normal tolerance of 10%. Some values are lower, some higher. I use an LC meter that has been checked to be accurate enough for my needs when assembling to tweak the coil before I solder it into the circuit. Using the calculator from the company that makes the toroid would be better, as any discrepancies in the mix should be incorporated into the calculation. I have not tried the multi-winding toroids, as I have not had to go back and do an LTspice simulation on any of those circuits. This could have a large discrepancy as the winding would be squeezed together to make room for the other winding increasing the effective inductance. Maybe that is the reason for your comment. Each person may have different experiences that guide them to different conclusions. That is OK, as long as we respect the other point of view. I will share my experience, not try to force my ideas on you. I am also open to feedback that I can use to get different points of view. 73 Evan AC9TU
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All the inductance values of all the toroids are in your manual. You did use the manual, didn't you? Jim W4JED On 6/28/22 15:03, kf7rcm via groups.io
wrote:
QCX+ 20 and 40 meters.
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Manual?
:-)
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Gary Bernard
You did download the manual, right?
Gary W0CKI
-----Original Message-----
From: kf7rcm via groups.io <kf7rcm@...> To: QRPLabs@groups.io Sent: Tue, Jun 28, 2022 4:05 pm Subject: Re: [QRPLabs] Toroid values #toroid Manual?
:-)
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Dennis Rieger
There is a chart on page 2 of the low pass filter manual showing values of C and L for LPF's from 2200m through 2m. Go to https://qrp-labs.com/lpfkit.html to find a copy of the manual. These LPF values should be consistent for all the kits. The only change might occur if a T37-6 is replaced by a T50-6. The value of L will stay constant but the number of turns will change for different core types. KK5DB
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Ok, I want to be a smart Alek and say no or something as bad, but I will assume your question is on the level.
Yes, I did. I will take this opportunity to state here for the record that I was so excited to get this little rig that I am positive that I built WAY too fast to have done it the way the designer intended, reading through the entire set of instructions first would have been a good start. Plus, I have not built anything quite like this before, it is pretty dang small and crowded. I have a 20m one and a PA coming soon with a dummy load and a few other items. I have every intention of exercising a build speed that will make glacier movement seem faster. I have learned and re-acquainted myself with so much that I don't entirely regret this first build. There is a very helpful HAM not far away from me that will take a look at this build and let me know what thing(s) I did incorrectly, and I really appreciate all of the helpful comments I have received from so many helpful people. I have to say that the niche that is "CW operators" seems to be a cut above when it comes to being helpful and encouraging, Wayne/Kf7rcm.
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Gary Bernard
Wayne, I’ve been following your thread. I saw the recent one that said. “Manual?” You have said several times that you rushed through the build.
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I’m 81 and have built mini’s, pluses and a couple of classics. Many worked the first time, some didn’t. First time builders need to pay very close attention to the manual, super close. I’ve needed lots of help on a mini. Anyhow, I wasn’t trying to be funny and I hope you get yours going. Yes, there’s help from this forum. 73, Gary W0CKI
On Jun 28, 2022, at 7:00 PM, kf7rcm@... via groups.io <kf7rcm@...> wrote:
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Thanks for messaging me Gary. That "come back" was directed at someone(s) else, just my way of asking them to not take themselves too seriously. apologies for any confusion.
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Al Holt
The QRP Labs LPF assembly guide states the design is based on "the GQRP Technical Notes, a design by Ed Wetherhold, W3NQN." George Dobbs, G3RJV, wrote this datasheet, which I think may be the one referenced: http://www.gqrp.com/harmonic_filters.pdf
If you'd like to see the current version of these notes, http://www.gqrp.com/technical2.htm will lead you to http://www.gqrp.com/Datasheet_W3NQN.pdf. In this second document you'll see the design has changed slightly by improving second harmonic filtering. Also see: https://www.arrl.org/files/file/Technology/tis/info/pdf/9902044.pdf which look like a a more detailed version by Ed. Also there's this article by Ed published by ARRL on designing Band Pass Filters: https://www.arrl.org/files/file/Technology/tis/info/pdf/9805044.pdf. And this more general introduction to RF and AF filters by ARRL: http://www.arrl.org/rf-and-af-filters Hope this helps! --Al WD4AH
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It does, thank you,
W.
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Gary Bernard
No apology necessary. I hadn’t built a kit in many years when I took on one of the original classics. That one never worked. It went in the bin and the bin is gone.
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Gary W0CKI
On Jun 28, 2022, at 11:19 PM, kf7rcm@... via groups.io <kf7rcm@...> wrote:
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Syd
I had some alignment problems with my QCX kit and had to resort to pulling out all the toroids and rewinding them with my VNA to the listed inductance values. and all of a sudden, the unit came into alignment very easily! So probably the values were off quite a bit.
73 wt1v
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