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I can’t figure out how to send a photo to post… Found this morning when I was looking for an opamp. Actually found my bag of parts for my VNA, maybe I can finish my second one!

Hi Jerry
This the RF-IV adaptor and it is gold.
Not sold any more by VE3iVM
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Jerry
Sendt: 26. januar 2024 20:14
Til: [email protected]
Emne: [N2PK-VNA] photo

I can’t figure out how to send a photo to post… Found this morning when I was looking for an opamp. Actually found my bag of parts for my VNA, maybe I can finish my second one!

As Kurt said; the RF I-V PCB and parts (some common parts such as resistors are not included).

I still use the one I built years ago;

[img][/img]

(Hope the photo comes-through; I haven't used PostImage for years).

Its virtue lies in the measurement of low & high impedances, well out of any VNA's "comfort zone"; here is a measurement of a 10k 1/4-watt leaded resistor;

RF I-V fixture;

[img][/img]

Normal reflection bridge;

[img][/img]

Its frequency range is limited by the ferrite transformers; mine has a range from 0.5MHz to 100MHz.

The supplied ferrites are #61 material; I have an unbuilt kit like yours and may, one day, build it with a higher-permeability material to extend the lower limit.

Building the transformers requires some patience;

[img][/img]

and housing requires some thought as the connectors are irregularly-placed.

Kerry VK2TIL.

The RF-IV is one of the most frequent things I use with the N2PK-VNA. It's really excellent.
Here's a photo of my setup:

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I used RJ45 connectors to attach the RF-IV control pins to the N2PK VNA.

I use the RF-IV feature for exploring what components look like, since I don't have any other general-purpose impedance meter!
My N2PK VNA and the RF-IV sensor were created with the most recent boards (V5.x) that Ivan Makarov offered, with the built-in USB interface.
I'm quite interested in the VNWA, I might buy that one day, but I really? like the N2PK VNA. It was great value-for-money, even though it took me about a year to assemble it, acquiring the enclosure bits, cables, etc.

My N2PK VNA has engraved connector legends, they might be faintly visible in the photo. I got those done at such a low cost; in the UK, there are stores nationwide called Timpson; they do key cutting, and also wristwatch and baby spoon engraving etc., so I just asked the kid working there if he wouldn't mind engraving onto my alu box, and he did a fantastic job.


________________________________
From: [email protected] <[email protected]> on behalf of Kerry via groups.io <planningpower@...>
Sent: 27 January 2024 01:51
To: [email protected] <[email protected]>
Subject: Re: [N2PK-VNA] photo

As Kurt said; the RF I-V PCB and parts (some common parts such as resistors are not included).

I still use the one I built years ago;

[img][/img]

(Hope the photo comes-through; I haven't used PostImage for years).

Its virtue lies in the measurement of low & high impedances, well out of any VNA's "comfort zone"; here is a measurement of a 10k 1/4-watt leaded resistor;

RF I-V fixture;

[img][/img]

Normal reflection bridge;

[img][/img]

Its frequency range is limited by the ferrite transformers; mine has a range from 0.5MHz to 100MHz.

The supplied ferrites are #61 material; I have an unbuilt kit like yours and may, one day, build it with a higher-permeability material to extend the lower limit.

Building the transformers requires some patience;

[img][/img]

and housing requires some thought as the connectors are irregularly-placed.

Kerry VK2TIL.

yes of course, I know what it is. I just have to find my original. I had two of everything. The plan was to build a second one using a lower phase noise oscillator and a better DDS. I got the 2nd about half build a while back and stalled for some reason. I think that was around when I broke my arm and couldn't solder for quite a while.

I found my RFIV box, but not the top or the connecting cable. I'll post a picture in the morning.

I also found an unpopulated dual detector board. I think it is the latest, but would have to verify it. If someone promises to build it, you can have the board and a decent oscillator, I think they are Connor-Winfield 25ppm, I can't remember, for the cost of shipping from California. In the US I would ship it flat rate, I think I have an extra DDS chip too, and if so, I would throw that in.

I have an oscillator that takes a 10Mhz reference input and outputs something above 126Mhz. It's low phase noise, something around -163dBc @100Khz but I never tested it. I wanted to build that 2nd VNA and I have it about 75% populated. Instead of a premium oscillator (one of the Connor-Winfields) and a better DDS, I think I would use LT3045 and LT3094 ldo regulators, and this oscillator that takes a reference. Those regulators are incredible. They will clean-up somewhat dirty supplies. I'm thinking about taking my VNA apart and putting them in. I can just jumper around the regulators that are in there. Back when I built my VNA, we were testing them to see how low the noise floor was and I think using the LT regulators, a better oscillator and a new DDS would be about the limit.

Anyway, I'm going to test my RFIV board in the morning if I can find the cable. I put a connector on the back and would hate have gone thru that trouble and not use it. I wish I could find the top as it had a cutout shield machined into it.

Speaking of home made test equipment, if you want to really go upscale, go here and build Andrew's Phase Noise test system. I did and it is amazing. He's added other features to it now.
In case you are wondering, if you get the Spartan board for around $500, and that's possible, then the rest of the setup will run another $500 by the time you get the ADC board and a pair of low phase noise reference oscillators. So for around $1000USD, you get a board that can outperform many PN test setups that are 10X expensive if not more.

Jerry