开云体育

One of the definitions for HP is High Price!!

*Clyde K. Spencer*


On Sun, May 18, 2025, 11:17?PM Charles VK1CM via groups.io <mrcharlesmuller=
[email protected]> wrote:

I nearly fell out of my chair when I saw the HP fixture prices. May I
suggest using these:



There is a lot of other goodies on his website, and I have found him very
easy to deal with.

Regards,


Charles.
VK1CM

OK, after looking more carefully at the photos, I think you're referring to the ratio of the desired signal through the device under test to the residual feedthrough with the device absent. Correct me if I'm wrong.

Did you consider the effect of the increased capacitance to ground at each port? It looks like it may be substantial. Easy to measure.

Brian

On Mon, May 19, 2025 at 09:40 AM, W0LEV wrote:

that old fixture was limited to about 35 dB of dynamic range

Dave, what do you mean by dynamic range in this context?

Brian

You've all seen my fixture I use for evaluating transmission measurements
on various items, especially common mode chokes, filters, and other
circuits.

Well, that old fixture was limited to about 35 dB of dynamic range over the
HF frequencies, nominally 1 through 30 MHz. One day I went to work using
various methods to up that dynamic range. I ended up with easily 75 dB of
range after about 2-hours of work on the older fixture using the HP3585
spectrum analyzer with its tracking generator. Yesterday, I verified that
75 dB of dynamic range using the HP8753C. With that instrument the fixture
measured closer to 80 dB of range over 1 to 30 MHz. Have a look at the
attached images for the physical construction. YMMV.

Dave - W?LEV


--
Dave - W?LEV

Yes. My last visit to JB was just after they closed. Sitting on the
concrete table outside the store was a Tektronix 7623A, with a sign on it
that read "FREE". You can guess what happened next. JB was the local parts
source for common parts for us at Benchmark. As far as I know JB was the
last surplus store (of the four that existed back in the 90s) to close and
I'm guessing that no new ones have opened since.

My sister worked at Sandia and told me about the surplus store there.

And don't forget the StorageTek surplus store. My Simpson 260xi came from
there. It was basically free (maybe $5 or something like that).

DaveD
KC0WJN


On Mon, May 19, 2025 at 11:42 W0LEV via groups.io <davearea51a=
[email protected]> wrote:

Dave, we all miss J. B. !! I can't count the number of times we,
collectively, solved (unpaid consulting) design problem with unknown
designers in the isles of J. B. Saunders. And......, then found the parts
to buy. They are sorely missed ! ! !

And in New Mexico: The surplus sales at both Los Alamos and Sandia.

Dave - W?LEV

On Mon, May 19, 2025 at 3:33?PM Dave Daniel via groups.io <kc0wjn=
[email protected]> wrote:

And J. B. Saunders ....

DaveD
KC0WJN


On Mon, May 19, 2025 at 11:24 AG6CX via groups.io <edwmccann=
[email protected]> wrote:

And Yardley Beers, W0JF, a Boulder legend along with McGukins.

Ed McCann
AG6CX

On May 19, 2025, at 8:21?AM, Dave Daniel via groups.io <kc0wjn=

[email protected]> wrote:

?I severely miss McGuckins.

DaveD

On 5/19/2025 11:03 AM, W0LEV via groups.io wrote:
Any good hardware store may have them. Also a good electrical

supply

house. Likely, the chains will not have such items.

We have an excellent "have everything" and then some hardware store

in

Boulder. They are an independent.

Dave - W?LEV

On Mon, May 19, 2025 at 1:51?AM WB9YXA via groups.io <ahoffman1=
[email protected]> wrote:

Dave,

Where did you find the very large alligator clip shown in the

photos

in

the document? My usual sources aren't turning up anything big

enough

to

bite a bnc connector.

Just curious.

Andy

--
This email has been checked for viruses by Avast antivirus software.
www.avast.com

--

*Dave - W?LEV*


--
Dave - W?LEV

Dave, we all miss J. B. !! I can't count the number of times we,
collectively, solved (unpaid consulting) design problem with unknown
designers in the isles of J. B. Saunders. And......, then found the parts
to buy. They are sorely missed ! ! !

And in New Mexico: The surplus sales at both Los Alamos and Sandia.

Dave - W?LEV

On Mon, May 19, 2025 at 3:33?PM Dave Daniel via groups.io <kc0wjn=
[email protected]> wrote:

And J. B. Saunders ....

DaveD
KC0WJN


On Mon, May 19, 2025 at 11:24 AG6CX via groups.io <edwmccann=
[email protected]> wrote:

And Yardley Beers, W0JF, a Boulder legend along with McGukins.

Ed McCann
AG6CX

On May 19, 2025, at 8:21?AM, Dave Daniel via groups.io <kc0wjn=

[email protected]> wrote:

?I severely miss McGuckins.

DaveD

On 5/19/2025 11:03 AM, W0LEV via groups.io wrote:
Any good hardware store may have them. Also a good electrical supply
house. Likely, the chains will not have such items.

We have an excellent "have everything" and then some hardware store in
Boulder. They are an independent.

Dave - W?LEV

On Mon, May 19, 2025 at 1:51?AM WB9YXA via groups.io <ahoffman1=
[email protected]> wrote:

Dave,

Where did you find the very large alligator clip shown in the photos

in

the document? My usual sources aren't turning up anything big enough

to

bite a bnc connector.

Just curious.

Andy

--
This email has been checked for viruses by Avast antivirus software.
www.avast.com

--

*Dave - W?LEV*


--
Dave - W?LEV

And J. B. Saunders ....

DaveD
KC0WJN


On Mon, May 19, 2025 at 11:24 AG6CX via groups.io <edwmccann=
[email protected]> wrote:

And Yardley Beers, W0JF, a Boulder legend along with McGukins.

Ed McCann
AG6CX

On May 19, 2025, at 8:21?AM, Dave Daniel via groups.io <kc0wjn=

[email protected]> wrote:

?I severely miss McGuckins.

DaveD

On 5/19/2025 11:03 AM, W0LEV via groups.io wrote:
Any good hardware store may have them. Also a good electrical supply
house. Likely, the chains will not have such items.

We have an excellent "have everything" and then some hardware store in
Boulder. They are an independent.

Dave - W?LEV

On Mon, May 19, 2025 at 1:51?AM WB9YXA via groups.io <ahoffman1=
[email protected]> wrote:

Dave,

Where did you find the very large alligator clip shown in the photos in
the document? My usual sources aren't turning up anything big enough

to

bite a bnc connector.

Just curious.

Andy

--
This email has been checked for viruses by Avast antivirus software.
www.avast.com

Yes, when we can't find something at Ace, we head to Boulder. White Rock,
New Mexico also had something similar that "served" the lab at Los Alamos.

Good hardware stores are rare these days with all the chains.

Dave - W?LEV

On Mon, May 19, 2025 at 3:21?PM Dave Daniel via groups.io <kc0wjn=
[email protected]> wrote:

I severely miss McGuckins.

DaveD

On 5/19/2025 11:03 AM, W0LEV via groups.io wrote:

Any good hardware store may have them. Also a good electrical supply
house. Likely, the chains will not have such items.

We have an excellent "have everything" and then some hardware store in
Boulder. They are an independent.

Dave - W?LEV

On Mon, May 19, 2025 at 1:51?AM WB9YXA via groups.io <ahoffman1=
[email protected]> wrote:

Dave,

Where did you find the very large alligator clip shown in the photos in
the document? My usual sources aren't turning up anything big enough to
bite a bnc connector.

Just curious.

Andy

--
This email has been checked for viruses by Avast antivirus software.
www.avast.com

--

*Dave - W?LEV*


--
Dave - W?LEV

And Yardley Beers, W0JF, a Boulder legend along with McGukins.

Ed McCann
AG6CX

I severely miss McGuckins.

DaveD

--
This email has been checked for viruses by Avast antivirus software.
www.avast.com

Deepelec has not updated their firmware in several years and their architecture is not the same as your V3.

Why not open the case and disable the beeper? Put some tape across the output port or cut the PCB track.

Any good hardware store may have them. Also a good electrical supply
house. Likely, the chains will not have such items.

We have an excellent "have everything" and then some hardware store in
Boulder. They are an independent.

Dave - W?LEV

On Mon, May 19, 2025 at 1:51?AM WB9YXA via groups.io <ahoffman1=
[email protected]> wrote:

Dave,

Where did you find the very large alligator clip shown in the photos in
the document? My usual sources aren't turning up anything big enough to
bite a bnc connector.

Just curious.

Andy

--

*Dave - W?LEV*


--
Dave - W?LEV

Nizar,

Yes you need to use Enhanced response option for S21. It was created by DiSlord for these types of measurements.

On Sun, May 18, 2025 at 11:17 PM, Charles VK1CM wrote:

There is a lot of other goodies on his website, and I have found him very
easy to deal with.

Makis is a great guy, I have designed one of his products, a dual log detector board, , into a VSWR protection circuit, for my client, after he assured me of its continued availability. Tons of other great, useful products on his site, highly recommended.
73, Don N2VGU

This might help:

Hi Roger
I do not use enhanced response, indeed i dont use an unknownen function for me, i use SeeSi H4 SM NanoVNA + DiSlord 1.2.40 Firmware , Serial resistor with reasonnable 2cm legs only for 30Mhz maximum frequency use. Should i activate enhanced redponse??
73s Nizar

Hi folks,

I'm brand new here. I just got the NanoVNA-F V3 which is made by SysJoint.
Like with my other VNAs (a cheap small NanoVNA-H & a LiteVNA 64) the first thing I looked for was the (custom) firmware situation because the SysJoint NanoVNA-F V3 beeps every now and then and it's no possible to switch this off (I asked the SysJoint support).
So I was wondering ... I learned that there's another official manufacturer of the NanoVNA-F, Deepelec, and read that its firmware can be flashed onto a SysJoint NanoVNA-F, too?
But has the Deepelec firmware an option to switch any beeping off?
Are there other firmwares that can be flashed onto my SysJoint NanoVNA-F V3?

Thanks a lot & all the best,
Stefan.

I nearly fell out of my chair when I saw the HP fixture prices. May I
suggest using these:



There is a lot of other goodies on his website, and I have found him very
easy to deal with.

Regards,


Charles.
VK1CM

Dave,

Where did you find the very large alligator clip shown in the photos in the document? My usual sources aren't turning up anything big enough to bite a bnc connector.

Just curious.

Andy

On Sun, May 18, 2025 at 11:39 AM, Dan Pate - AI5OL wrote:

I fabricated a test lead that is a coax that terminates in a pair of alligator
clips. I clip the leads onto a panel mount SMA connector to attach the
Open/Short/Load calibration standards to calibrate to the reference plane at
the alligator clips. I can then clip the leads to the connections of the coil
to test.

Alligator clips are OK if you just want to get a rough idea of the impedance of the device you are measuring. The problem with them is you have an impedance discontinuity from the coax to the clips which can only be partially "calibrated out". Also when you calibrate the clip separation and lead spacing is different that when you are measuring the DUT. This all results in a poor reference plane.

Below is a measurement I did of a small inductor. It was tested at 100 kHz. on a DE-5000 LCR meter and then measured using alligator clips and a proper test jig. The results and comments are in the graphs.

Roger