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The earlier comments about mismatch and cable length are probably correct. You said you checked the SWR at the connection to the transmitter and it was correct. Now take the MFJ out of the circuit and use the NanoVNA to check the antenna SWR at that connector to see what it reads. Depending on the actual SWR at the ANTENNA, you can get radically different results at 2M from just a few inches of added cable length.

Once upon a time I was installing a quarter-wave whip on my car. Just installed the mount, ran the coax, and put a connector on the cable. I could NOT get a whip to work in the 2M band! I tried about 6-8 different whips ranging from 132MHz to 174MHz, and they all read fine as predicted by length, except the whips cut for the 2M band. I eventually cut 6" off the coax, installed a new connector, and all the whips read as they should. I just happened to have a cable length that was a resonant length around 145-148MHz and no antenna would give a good SWR in that range.

If you want to understand the problem, check the Handbook or search the web for explanation of how to use quarter-wave matching sections in antenna systems. Or just read some articles about using quarter-wave coaxial stubs.

If you want to SEE the problem with your NanoVNA, connect the two SMA cables to the VNA and join the far ends with a SMA Tee connector. This is effectively what you have when you to the "Thru" calibration of the VNA so the result should be a flat line in your mode of choice. Then find a short stub of coax with a connector on one end and noting on the other end of the coax. Attach that to the Tee and check the return loss or SWR sweep on the VNA. At the frequencies where the cable has a resonance you will see dips or peaks on the screen.

You may have trouble seeing it on the VNA at max bandwidth because it only has 101 test points, but if you narrow down the frequency range to maybe 150-200MHz with a coax stub length around 12-14 inches, I'm guessing you will see a disturbance in the display when you connect the cable. The actual frequency depends on the cable length and velocity factor of the coax, so I can't guess any closer what the frequency will be with your coax stub. For extra credit, short the end of the coax with a pin or short wire and see what happens. Look it up in the previously mentioned articles to find out why that happened. :-)

73, Doug, N0NAS.

I am not the best source for info regarding duplexor tuning but I have done over 30 of them for hams in my local area. I'm not really aware of ANY of the cheap spectrum analyzer-tracking generator boards that can really do the work to get below 70-80dB rejection, just as others have said. Many duplexors are good enough that even good commercial equipment has trouble getting down to the bottom of the notch.

If you want some good direction and explanation of the process, YouTube is your friend. I've found some excellent duplexor tuning videos out there. Don't stop with the first one, watch a bunch of them to get all the tips and tricks, and also to help filter out the poor videos. And most of the major duplexor manufacturers have some very well written documentation to explain how to tune their equipment. The general steps are all the same, but details can vary.

Regarding that last 20-30dB of tuning, the further down you can tune with the NanoVNA or other hardware, the better off you are. Tune the notch as good as you can and as symmetrically as you can. I've used my DG8SAQ VNWA3 to tune duplexors before. When I get the notch tuned as well as possible, I used to disconnect the signal source from the duplexor and replace it with a HT set on low power. That gets me an extra 20-30dB of signal and I can tune the notch deeper. You should also put a 6dB pad between the HT and duplexor to make sure the input impedance is still near 50 ohms.

TWO WARNINGS about this method.... It is extremely easy to blow the VNA using this method. Don't blame me if it happens to you!

First, don't adjust anything very far from the notch center since the signal reaching the VNA can rise quickly and let the smoke out... If the duplexor adjustments are "touchy" you might not want to try this. (You probably should do some maintenance first....)

Second, not all HT radios are created equally... Some have a LOT of spurs, and some don't properly kill the TX when the VCO isn't locked. I blew up my VNWA3 when I keyed my VX1 HT and it swept in to operating frequency while transmitting at full power. Just a few 100mw, but it went well outside the duplexor notch and sent that RF to the VNWA3 mixer. It took it a few times before theVNWA lost about 40dB of sensitivity. After it blew, I tested the VX1 over a wider frequency range and could see the signal as it swept in to phase lock. So be careful!

For a less dangerous option, just remember that the NanoNVA is listed as -13dBm output. Most commercial signal generators will go to at least +20dBm output. That gets you an extra 30dB of notch depth from a stable and clean signal source. But you need to be REALLY careful with your connections and frequency changes. Don't screw up!

73, Doug, N0NAS.

Latest version reintroduces 300MHz threshold crossover anomaly. I did not attempt to correct thru threshold adjustment. Otherwise, seems stable. Calibration and various device tests were successful.

Peter

Good, ok i change 96kHz mode for AIC ADC (now increased external freq), possible it help (on my H4 it also give good result)

Also i change IF to 8kHz (in my test got less noise)
Additional not use float type variable on DSP (float type can lost data) it allow more correct measure low level signal (it only for H4, processor have hardware DSP instruction support)

Need reset old calibration settings

PS made test CH1 port use up to 80dB attenuator, get this measure result (on high freq better use high bandwidth for better result)
-85dB on 1-300MHz
-70dB on 300-900MHz
-50dB 0n 900-1500MHz
-40dB on 1500-2400MHz
-30dB on 2400-2700MHz

On Sat, Apr 25, 2020 at 12:32 PM, Peter Finch wrote:

... This latest firmware version with reduced DAC sample rate is stable on my H4.

As an aside, there is no harmonic anomaly around 300MHz. Plots are clean with the unchanged threshold setting of 300MHz on tight sweeps of 295-305MHz, 299-301MHz, and 299.99-300.01MHz....
==========================================

Good news! Peter,
Thanks for the feedback. I'm sure finding out about issues like yours is why DiSlord has released his beta versions to this group. Whatever advantages the 96 kHz DAC sample rate may have, if it causes problems on some NanoVNA's then hugen would not want to include it in his final release.

After enjoying the new bandwidth, sweep points, lower start frequency and increased sweep rates I would be broken-hearted if I had to go back to the stock firmware.

- Herb

This latest firmware version with reduced DAC sample rate is stable on my H4.

- I ran it on a short connector for 20 minutes with no error drift over time in the display.
- I was able to successfully calibrate the H4 (using 201 sweep points Woo! Hoo!).
- The displayed plots match previous plots for known DUTs.
- NanoVNASaver no longer reports data out of range errors.

As an aside, there is no harmonic anomaly around 300MHz. Plots are clean with the unchanged threshold setting of 300MHz on tight sweeps of 295-305MHz, 299-301MHz, and 299.99-300.01MHz.

Thank you!

Peter

On Sat, Apr 25, 2020 at 07:38 AM, hwalker wrote:

A hugen distributed 4-inch 3 GHz S-A-A-2, in a case with SOLT standards and
cables for under $100 would create it's own market.

I'd buy one in a heartbeat!

Awesome, I will see if some of the locals are interested.
Thanks

The PCB+partial PCBA would cost around ~$50 for 2pcs, and only slightly

On Sat, Apr 25, 2020 at 09:11 AM, Gabriel Tenma White wrote:

Right now my biggest task on the firmware is adding moonrunes support which a lot of their domestic users are asking for.
======================================

Thanks for clarifying Gabriel. I had to look up "moonrunes" as I'm not familiar with the term. Am I correct in believing that it is to add Japanese characters as a language option?

- Herb

A little note. The response of such very sensitive devices can be

expected to shift a little when connected in the field. The bench tuning
is a start. The tuning is completed up at the site by tweaking when all
connections have been made.

+++++


On 2020-04-25 8:12 a.m., Lawrence Macionski via groups.io wrote:

I am not the 1st to respond, but I have used my NanoVNA to tune a 6 cavity Waco VHF and a 4 cavity, "Cigar tube" UHF duplexer (Ritron). Regarding notches When you approach 70db attenuation, the graph gets "noisy".. With a NanoVNA use at least 2 passes per 1Mhz. It's slow but seems to get the job done. Since you can not resolve -90-100dB with the NanoVNA. I opted to "imagine" the dip to continue below a smoothe line in the area of the noisy bottom.
I used a marker on my desired frequencies and tuned so that the marker was midway between the noisy area of the notch.. I hope I am expressing the theory that the "dip" is symmetrical, and "down in the noise". Having the marker frequency set mid-way in the noisy area should "guesstimate" the lowest point of the notch. I did save a snapshot of my start as you can see the notch area is off. The markers are 144.67-145.27...Ideally you want the marker in the middle of the notch noisy area..Not everyone is rich nor has access to expensive commercial test gear. 40 years ago I watched a guy tune duplexers with an 10 watt transmitter, a receiver. a VTVM, 140 feet of RG-58 coax and a step attenuator. He made the duplexers out of old soda water fire extinguishers.

--

John

at radio station VE7AOV

I am a partner of SYSJOINT, and I must clarify that BH5HNU used to be an employee of SYSJOINT. He was responsible for NanoVNA-F project, and -F was originally sold through SYSJOINT's Aliexpress shop(hamelec.aliexpress.com), but when -F became popular and produced some benefits, BH5HNU betrayed SYSJOINT under the drive of interests. He left SYSJOINT and continued to produce and sell -F in the name of deepelec, we still have some legal disputes with BU5HNU and his new company.

BU5HNU has always claimed that he is the original designer of -F, which literally seems to be true, but the truth is that an employee leaves the company and starts to manufacture and sell the same products as the former owner. What do you think of this behavior？

By the way, as an open source project, BH5HNU only released the source code of version 0.0.4，he did not publish the source code of subsequent versions. This has violated the open source software license. edy555, the original creator of nanovna may need to pay attention to this issue. By the way, SYSJOINT will continue to develop new firmware and publish the source code on github.

On Sat, Apr 25, 2020 at 08:05 AM, Gabriel Tenma White wrote:

Yeah sure, just change up the layout a bit, space things out, try to make it look like it's not a verbatim copy ;)
==========================================
Gabriel,
I asked hcxqsgroup about a 4" S-A-A-2 and they responded:

"The 4’’ screen version is awaiting firmware support and PCB re design, which may take a few more months."

I understand they are waiting for your 4" firmware support but I wasn't expecting "months" for that to occur. The PCB re-design should only require enlarging the current board to allow mounting holes the plug-in 4" (3.95") display module.

I also asked about my pet peeve of the S-A-A-2 going into "USB Mode" whenever a command is sent to it and requiring power cycling to exit. They responded:

"The exiting USB mode problem is being worked on and should be fixed by next firmware release in a week or so."

So I assume this is something you are currently working on unless hcxqsgroup has taken over some of the firmware and software support. It's not clear to me what the current relationship is between hcxqsgroup and OwOComm regarding software, firmware, and hardware support.

- Herb

I am not the 1st to respond, but I have used my NanoVNA to tune a 6 cavity Waco VHF and a 4 cavity, "Cigar tube" UHF duplexer (Ritron). Regarding notches When you approach 70db attenuation, the graph gets "noisy".. With a NanoVNA use at least 2 passes per 1Mhz. It's slow but seems to get the job done. Since you can not resolve -90-100dB with the NanoVNA. I opted to "imagine" the dip to continue below a smoothe line in the area of the noisy bottom.
I used a marker on my desired frequencies and tuned so that the marker was midway between the noisy area of the notch.. I hope I am expressing the theory that the "dip" is symmetrical, and "down in the noise". Having the marker frequency set mid-way in the noisy area should "guesstimate" the lowest point of the notch. I did save a snapshot of my start as you can see the notch area is off. The markers are 144.67-145.27...Ideally you want the marker in the middle of the notch noisy area..Not everyone is rich nor has access to expensive commercial test gear. 40 years ago I watched a guy tune duplexers with an 10 watt transmitter, a receiver. a VTVM, 140 feet of RG-58 coax and a step attenuator. He made the duplexers out of old soda water fire extinguishers.

On Sat, Apr 25, 2020 at 06:00 AM, <hugen@...> wrote:

If you allow it, we look to produce a 4-inch S-A-A-2 for less than $80.
==========================================================
Gabriel,
It would be great to have a second source for the S-A-A-2. hugen is a reputable and trustworthy seller. He also knows the in's and out's of manufacturing, distribution and user support in the far east. If it is legally possible, you should give strong consideration to hugen as a second production source.

We know you are currently working on S-A-A-2 firmware support for a 4-inch display. A hugen distributed 4-inch 3 GHz S-A-A-2, in a case with SOLT standards and cables for under $100 would create it's own market.

- Herb

What a twist!:)

On Sat, Apr 25, 2020 at 02:54 AM, Gabriel Tenma White wrote:

I got message from the seller that they are frustrated with selling direct.
One user for example wrote a negative review saying it didn't arrive only 24
days after buying, while it clearly says on the website that the expected
shipping time is 25 to 45 days and probably longer due to covid-19, with a
promise to refund or reship if it's not delivered in 60 days. They reply to
all messages on time and yet there are reviews saying they don't reply to
emails. There are other manufacturers coming to me about the V2 design, but
most of them said they won't sell it at this price. Oh well, it's a good thing
I designed this to be easy to build at home for hobbyists.

If you have already received your V2 I guess you can help them by writing a
review.

如果您允许，我们看可以生产低于80美元的4英寸厂-础-础-2.

From: David Eckhardt

Spectrum analyzer plus tracking generator.
=========================================

Poor man's 70 MHz-6GHz version:



Cheers,
David
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

If you're planning n buying one I suggest the -H4. It goes to over 1Ghz, has TDR already loaded and is available from R&L Electronics for $60 or so which is a fine price. I've one and really like the larger screen vs the original nanovna which I also have.

Ron
N4XD

Hello Herb and others,

We already have official support at the /g/NanoVNA-V2/ group,
user *nanov2support *from the HCXQS group.

Cheers.




*73 de Luís, CT2FZI*

*QRV @ 145.300 MHz | **CQ0VMST (VHF REP Monsanto)*
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Hi Gabriel, I can only say they respond in a very correct way to emails. I asked if I could buy another one and get it sent by an express service like DHL or Fedex. Their answer:
The typical total delivery time for ePacket is 30 to 40 days. It may stay in the left origin country state for a few weeks as it goes through customs. If you don’t receive your order within 60 days we can ship another one or give you a refund.
Currently we are unable to ship DHL because our location is outside the coverage area of all major couriers. I will look into it further.

I ordered them March 6, I'll just wait a little longer for my 2 units to arrive. I will write an honest review when I get them.

Op 24-4-2020 om 20:54 schreef Gabriel Tenma White: