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Re: Variation in readings of R value
All, What about radiation from the coil? Another basic definition for Q relates to the energy stored / energy lost. If energy is lost to radiation that needs to be considered as well. Very interesting
By WB2UAQ · #33398 ·
Re: Best NANOVNA Version that displays reactance, not uH & C
Thank you Roger! Yep, looks like mine's older than that. Sounds like a firmware update will get me fixed up. That menu map is WAY more extensive than what I have. Looking forward to it! Thanks again!
By Tom AE5I · #33397 ·
Re: Best NANOVNA Version that displays reactance, not uH & C
The option was added to the firmware around January 2021. If yours is old update the firmware. Lots of nice features and bug fixes over the years.
By Roger Need · #33396 ·
Re: Best NANOVNA Version that displays reactance, not uH & C
Well, I see the Polar/Rect menu options, but I don't see anything about the nature of the reactance display. Mine must be from before they added that. What hardware and firmware do you have? (No rush,
By Tom AE5I · #33395 ·
Re: Variation in readings of R value
Thanks.
By alan victor · #33394 ·
Re: Best NANOVNA Version that displays reactance, not uH & C
Hi Roger- Thanks very much! I had looked for that and didn't find it, but I'll look again. Mine's pretty early. Might have been added between the time mine was made and yours? Thanks again... Back to
By Tom AE5I · #33393 ·
Re: Variation in readings of R value
Rules of thumb are handy, but today it's easy to directly optimize a coil design. The first image show's Mike's coil. The second shows it after optimizing turns and coil length. The third is after
By Brian Beezley · #33392 ·
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 ·