¿ªÔÆÌåÓý

ctrl + shift + ? for shortcuts
© 2025 Groups.io
Date
Re: Variation in readings of R value
Hi Mike. I suspect that the dielectric loss of your coil is secondary. A Qul of nearly 350 implies to me that the primary losses are likely copper wire R and fixture. A couple of useful things to do.
By alan victor · #33391 ·
Re: Variation in readings of R value
No I wouldn't use black for that reason. It's white (see photo further up this thread). It's solid, not foam. -- Mike
By Mike · #33390 ·
Re: Variation in readings of R value
Ohh. Black ABS? As in Drain Waste Vent (DWV) pipe? The black is from carbon black as a pigment - yeah, as in resistors Also, most DWV is what is known as "cellular" which means that the walls are
By Jim Lux · #33389 ·
Re: Variation in readings of R value
After all that debate about PVC I've just discovered that my coil former is actually ABS ... Apologies! -- Mike
By Mike · #33388 ·
Re: Variation in readings of R value
Thanks for all your comments, Jim. I think I've seen different dissipation factor values for PVC depending on filler amount. I believe I used values for pure PVC, but I can't remember. In any event,
By Brian Beezley · #33387 ·
Re: Variation in readings of R value
On Tuesday 04 July 2023 02:54:32 pm Jim Lux wrote: > On 7/4/23 11:16 AM, WB2UAQ wrote: > > Mike and Alan, > > I measured the loss factor for PVC and it was about 0.005 or so at 1 kHz. I did more
By Roy J. Tellason, Sr. · #33386 ·
Re: Variation in readings of R value
On 7/4/23 12:24 PM, Brian Beezley wrote: > On Tue, Jul 4, 2023 at 11:54 AM, Jim Lux wrote: > >> >> PVC pipe has two potential problems as a coil form (based on experience of >> folks building tesla
By Jim Lux · #33385 ·
Re: Inductor model
Just 4 turns. The idea and constructive details came in 2015 from Jim Giammanco N5IB, the original designer of the PHSNA. Ignacio
By EB4APL · #33384 ·
Re: Variation in readings of R value
I asked Google AI whether PVC is hygroscopic. Here, in part, is what it said Polyvinyl chloride (PVC) is a hygroscopic powder material. Hygroscopic substances can take and hold moisture from the
By Brian Beezley · #33383 ·
Re: Variation in readings of R value
On 7/4/23 11:16 AM, WB2UAQ wrote: > Mike and Alan, > I measured the loss factor for PVC and it was about 0.005 or so at 1 kHz. I did more measurements at RF but will have to go back to old note books.
By Jim Lux · #33382 ·
Re: Variation in readings of R value
Mike and Alan, I measured the loss factor for PVC and it was about 0.005 or so at 1 kHz. I did more measurements at RF but will have to go back to old note books. I made a simple fixture to test a
By WB2UAQ · #33381 ·
Re: Variation in readings of R value
It's PVC water pipe. -- Mike
By Mike · #33380 ·
Re: Variation in readings of R value
Most coils have some parasitic C (it can be quite large). That C has a voltage on it, and a lossy dielectric leads to loss.
By Jim Lux · #33379 ·
Re: Variation in readings of R value
Hi Pete. The inductor is supporting a propagating field. It is both magnetic and electric. You are correct, while the magnetic properties of a core are key to control loss, so are the dielectric
By alan victor · #33378 ·
Re: Best NANOVNA Version that displays reactance, not uH & C
You can change the setting in the menu to display R+jX instead of the default R +inductance/capacitance. Roger
By Roger Need · #33377 ·
Re: Variation in readings of R value
Alan, How does the loss factor of the dielectric that the coil form is made from impact the magnetic circuit? I have heard others mention this but with no explanation. Thanks, Pete
By WB2UAQ · #33376 ·
Best NANOVNA Version that displays reactance, not uH & C
Good evening! I would very much appreciate recommendations on the best version of the NANOVNA that displays reactance values for the markers on the Smith chart, instead of inductance and capacitance.
By Tom AE5I · #33375 ·
Re: Variation in readings of R value
Excellent Mike. So that is a Qul of 348. I spilt the difference between 6 and 8 ohms... lets say 7... From the appearance of your coil, that seems reasonable. The material you wound the unit on has a
By alan victor · #33374 ·
Re: Variation in readings of R value
OK I had a go at this with my NanoVNA and got the attached result, which if I follow your calculation correctly equates to Rq = 8.05 ohms. Coil64 estimates 5.9 ohms which, given the less than ideal
By Mike · #33373 ·
Re: nanoVNA-H net com usb port
Return it and get a refund. Then go to R & L Electronics and purchase a genuine one. Problem solved!!! PS... This is the very best advise ANYBODY can give you!!!
By Dentron · #33372 ·