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U3S toroid - 2200m to 160m

N1BUG All Messages By This Member #16782 What is the consensus on single 25 turn vs. 10 turn bifilar if the primary focus is low and medium frequencies? Is there any issue installing the bifilar wound toroid laying flat in order to fit the OCXO? I am finally getting around to build my U3S with all the trimmings (OCXO, GPS, etc.) 73, Paul N1BUG
JT Croteau All Messages By This Member #16790 I'm interested as well, I am building a U3S to cover 600/160/80. 72, John N1ESE toggle quoted message Show quoted text On Mon, Oct 9, 2017 at 6:39 PM, N1BUG <paul@...> wrote: What is the consensus on single 25 turn vs. 10 turn bifilar if the primary focus is low and medium frequencies? Is there any issue installing the bifilar wound toroid laying flat in order to fit the OCXO? I am finally getting around to build my U3S with all the trimmings (OCXO, GPS, etc.) 73, Paul N1BUG
JT Croteau All Messages By This Member #16851 N1BUG, the manual has a nice chart showing power differences between standard and bifilar winding. It looks to me that winding bifilar makes a big difference to us on the lower frequencies, a several hundred mw gain in fact. I'm nervous about trying to wind bifilar but I'm going to have to give it a go. 72, John N1ESE toggle quoted message Show quoted text On Tue, Oct 10, 2017 at 2:29 AM, JT Croteau <jt.tobit@...> wrote: I'm interested as well, I am building a U3S to cover 600/160/80. 72, John N1ESE On Mon, Oct 9, 2017 at 6:39 PM, N1BUG <paul@...> wrote: What is the consensus on single 25 turn vs. 10 turn bifilar if the primary focus is low and medium frequencies? Is there any issue installing the bifilar wound toroid laying flat in order to fit the OCXO? I am finally getting around to build my U3S with all the trimmings (OCXO, GPS, etc.) 73, Paul N1BUG
N1BUG All Messages By This Member #16852 John, that chart in the manual is what led to my question. The data doesn't appear to go below 2 MHz. Toward the lower frequencies (left) on the safe power graph it appears the standard (25 turn) and bifilar are converging. That made me wonder what happens at 472 or 136 kHz. If the trend continues it looks as though the 25 turn winding could actually be better down there. Of course I can try both ways myself and see which works best, but thought I would ask to see if anyone has already done that. I prefer not to remove parts from a PCB once they have been soldered. There may be even better methods if one is only interested in the low frequencies. Perhaps more turns or a different material core. Don't worry. Bifilar winding is not difficult. The hardest part is getting twists in the wire but even if they are not perfect it usually works fine. 73, Paul N1BUG toggle quoted message Show quoted text On 10/11/2017 10:00 AM, JT Croteau wrote: N1BUG, the manual has a nice chart showing power differences between standard and bifilar winding. It looks to me that winding bifilar makes a big difference to us on the lower frequencies, a several hundred mw gain in fact. I'm nervous about trying to wind bifilar but I'm going to have to give it a go. 72, John N1ESE On Tue, Oct 10, 2017 at 2:29 AM, JT Croteau <jt.tobit@...> wrote: I'm interested as well, I am building a U3S to cover 600/160/80. 72, John N1ESE On Mon, Oct 9, 2017 at 6:39 PM, N1BUG <paul@...> wrote: What is the consensus on single 25 turn vs. 10 turn bifilar if the primary focus is low and medium frequencies? Is there any issue installing the bifilar wound toroid laying flat in order to fit the OCXO? I am finally getting around to build my U3S with all the trimmings (OCXO, GPS, etc.) 73, Paul N1BUG
Chris Wilson All Messages By This Member #16853 Hello Paul N1BUG, If you are just using your U3S on 2200m to drive a Class D amp you don't need the toroid at all, just take drive direct from the Si chip CLK0 pin. If you use the very latest firmware you can delete the phase inverter IC and drive the FET driver IC directly from CLK1 and CLK2 Are you about to start RX on 2200m any time soon again? Good luck. Monday, October 9, 2017 toggle quoted message Show quoted text What is the consensus on single 25 turn vs. 10 turn bifilar if the primary focus is low and medium frequencies? Is there any issue installing the bifilar wound toroid laying flat in order to fit the OCXO? I am finally getting around to build my U3S with all the trimmings (OCXO, GPS, etc.) 73, Paul N1BUG -- 2E0ILY Best regards, Chris mailto:chris@... -- Best regards, Chris Wilson (2E0ILY)
John Backo #16856 John: Winding bifilar or trifilar is easy if you wind the wire beforehand. Take two or three pieces of wire about 6' long and attach one end to something solid. Then carefully align them so that they are of uniform length into a bit holder of an electric drill (preferably a variable speed one). Bring the wires taut and slowly wind them together with the drill. You are finished when you have a "twist" of about 4-6 turns per inch. This will give you a uniform winding, and a 4-5' piece of dual or triple wire for all your projects. (Yes, these windings are very common in homebrew projects). This is pretty much a standard way of doing it; YRMV. The nice thing is that it doesn't matter too much what the wire gauge is -- even mixed gauges will work ok if they are not too far apart. Hope this helps. Hi. john AD5YE
N1BUG All Messages By This Member #16879 Hello Chris, Unfortunately I have no big amp of that type. I will be building a 25-50 watt HB9ASB LF/MF amp as described on the QRP Labs site. Apparently it benefits from somewhat more drive. My RX status this year is uncertain but surely won't be as good as last year. More on that shortly. 73, Paul N1BUG toggle quoted message Show quoted text On 10/11/2017 12:07 PM, Chris Wilson wrote: Hello Paul N1BUG, If you are just using your U3S on 2200m to drive a Class D amp you don't need the toroid at all, just take drive direct from the Si chip CLK0 pin. If you use the very latest firmware you can delete the phase inverter IC and drive the FET driver IC directly from CLK1 and CLK2 Are you about to start RX on 2200m any time soon again? Good luck. Monday, October 9, 2017 What is the consensus on single 25 turn vs. 10 turn bifilar if the primary focus is low and medium frequencies? Is there any issue installing the bifilar wound toroid laying flat in order to fit the OCXO? I am finally getting around to build my U3S with all the trimmings (OCXO, GPS, etc.) 73, Paul N1BUG

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