nanovna-users@groups.io

Re: NanoVNA measurement of an EFHW Transformer

Gary

If I understand you correctly, connect both primaries together - connect them to port 1 and both secondaries together - connect it to port 2 and have the nanoVNA compute s21.   Do they sell solder pads that have SMA connectors to facilitate this? or do I just connect the center connectors of the SMA to each of the ends of the two transformers that are back to back?

Thanks Gary

Ariel NY4G

Show quoted text

On Mar 13, 2021, at 09:48, Gary W9TD <w9td@...> wrote:

?Most accurate way is to use two of them back-to-back and the loss of one is half the total loss. Another way would be to terminate it in the correct value of resistance and measure the voltage across the resistor with a good scope.
Gary
W9TD

Re: NanoVNA measurement of an EFHW Transformer

#21337

Most accurate way is to use two of them back-to-back and the loss of one is half the total loss. Another way would be to terminate it in the correct value of resistance and measure the voltage across the resistor with a good scope.
Gary
W9TD

Re: nanovna saver

#21336

"Instead of FSK, the C64 uses square-wave pulses of three different lengths (352, 512, 672 ?s). Each byte consists of 9 bits stored as either a short then medium, or a medium then short - so the total length of each bit is constant. This is followed by a 10th marker bit which includes a long pulse and usually a medium pulse. Thus the total length of each byte is 672+9*352+10*512 = 8960?s, or 111.6 bytes per second raw."1.

So... Keep in mind, I was in my upper 20's when the C64 came out. I calculate at the 111.6 bytes per second, it would take the nano saver program, with is 76.167KB about 682,500 seconds to load. That would 11,375 min or 189 hours or 7.9 days to load the program by tape to a C64 (if it could).

1. !

-- 
Doug Rich

Re: nanovna saver

#21335

There is no reason for it to take that long.
On linux on a fairly old machine it starts
under 3s.

On Sat, 13 Mar 2021 at 14:20, Rod Mollise <rodmollise@...>
wrote:

I could run it on my Alienware in the house and get it to start up quicker
(if not exactly quickly, I'd guess)...but...I'm happy enough with it on the
shack PC. Yes, it takes a minute or two to start, but so what? Once it is
running, its performance is top-notch, OM. :)

NanoVNA measurement of an EFHW Transformer

#21334

Is there someone in this group that has measured the loss associated with a transformer of this type and can steer me either to a thread or a discussion on how this was done?

Much appreciated response

Ariel NY4G

Re: nanovna saver

#21333

I could run it on my Alienware in the house and get it to start up quicker (if not exactly quickly, I'd guess)...but...I'm happy enough with it on the shack PC. Yes, it takes a minute or two to start, but so what? Once it is running, its performance is top-notch, OM. :)

Re: nanovna saver

#21332

On Thu, Mar 11, 2021 at 08:44 PM, Bear Albrecht wrote:


it sees my Gecko plugged in, but it won't connect.
Is the PC software set (seeing, connecting) to the correct port number?  Did you use 'Device Manager' to find the nanovna's port number?

-- 
Doug, K8RFT

Re: nanovna saver

#21330

Back in 1982, my Atari computer loaded and started programs faster than that - from cassette tape! :-)

Re: Larger Text on Menus.

#21329

I installed the 2021-01-30 version for my H. Huge improvement, thanks
again, Gary!

On Fri, Mar 12, 2021 at 12:01 PM stefan baartman via groups.io <seb21051=
[email protected]> wrote:

Hi Gary, much appreciated!

On Fri, Mar 12, 2021 at 11:59 AM Gary W9TD <w9td@...> wrote:

Install the latest hugen79 firmware, it has text suze like the tinySA.
Gary
W9TD

Re: Larger Text on Menus.

#21328

Hi Gary, much appreciated!

Show quoted text

On Fri, Mar 12, 2021 at 11:59 AM Gary W9TD <w9td@...> wrote:

Install the latest hugen79 firmware, it has text suze like the tinySA.
Gary
W9TD

Re: Larger Text on Menus.

#21327

Install the latest hugen79 firmware, it has text suze like the tinySA.
Gary
W9TD

Re: nanovna saver

#21326

On Sun, Mar  7, 2021 at 02:49 PM, Clyde Lambert wrote:


It takes about 1 to 2 minutes to actually start on my Windows 10 machine.
Until then, all I see is a screen that looks like a dos screen.
Yes, that's normal.  I see it every time, too.  Let it finish loading, and it will work.

-- 
Doug, K8RFT

Larger Text on Menus.

#21325

I don't know if this request has ever come up, but I find the text on the menus difficult to read, whereas on the TinySA, it is much easier to do so. My eyes are not what they used to be, so I was wondering what it would take to make the text larger.