开云体育

I would like to calibrate duplexer with nanovna is there someone who can
help me.

It really depends upon whether the duplexer is a pass only or a pass notch.

There are multiple methods so I will give one procedure.

1. Connect the duplexer antenna port on a good 50 ohm load.
2. Connect the duplexer Rx port on a 50 ohm load.
3. Calibrate the NANOvna as usual.
4. Connect the NANOvna to the duplexer TX port and set the NANAvna to
measure return loss.
5. Set the start frequency at least 5 MHz below the desired frequency.
6. Set the stop frequency to at least 5 MHz above teh desired frequency
7. Find the dip in the display and note the frequency.
8. Adjust the duplexer transmit cans while watching the vna display moving
the dip to the desired frequency.
9. Once close to the desired frequency change the start and stop
frequencies to 1 MHz below and 1 MHz above.
10 .Fine tune until the dip as as close to teh desired frequency as
possible.
11. remove the vna from the Tx port and place it on the Rx port.
12. Put the RF load on the Tx port.
13. Perform steps 5 though 10 for the receive frequency.

If this is a pass-notch duplexer then you have to set the notch frequencies.

14. Perform steps 1 though 3 above.
15. Connect the vna to the Tx port but set the center frequency of the vna
to the Rx frequency.
16. Adjust the notch to the desired Rx frequency.
17. Place the vna on the Rx port and the load on the Tx port.
18. Adjust the Tx notch for the desired frequency.

Once the tuning is complete the a throughput test can be performed,
19. Re-calibrate the vna from 1 MHz below and 1 MHz above the Tx frequency.
20. Be sure to do the S21 isolation and throughput calibration.
21. place a load on the Rx port.
22. Connect the vna port 0, or port 1 depending upon the NANOvna at hand,
to the Tx port of the duplexer.
23. Connect the vna port 1, or port 2 depending upon the NANOvna at hand,
to the duplexer output port.
24. Measure the throughput loss of the duplexer Tx leg.
25. Re-calibrate the vna to 1 MHz below and 1 MHz above the the Rx
frequency.
26. Connect the vna port 0, or port 1 depending upon the NANOvna at hand,
to the Rx port of the duplexer.
27. Put the 50 load on the Tx port.
28. Measure the throughput loss of the duplexer Rx leg.

Hope this helps.


*Clyde K. Spencer*



On Fri, Apr 24, 2020 at 11:08 AM Aurelien Voyer <aurelienvoyer@...>
wrote:

I would like to calibrate duplexer with nanovna is there someone who can
help me.

CAUTION: The NANOVNA's do not have the required dynamic range to properly
tune a set of duplexers (cans). A properly tuned set of cans, 6 of them in
BPBR configuration, will typically exhibit somewhat in excess of 100 dB
isolation between transmit and receive frequencies. The pass for each side
should exhibit about 1 dB of loss. The NANOVNA's do not have sufficient
dynamic range (best case at HF through low VHF is about 70 to 80 dB) to
accomplish proper duplexer tuning. One can get close, but the important
last 15 or 20 dB just isn't there with the NANOVNA's.

Dave - W?LEV

On Fri, Apr 24, 2020 at 9:08 AM Aurelien Voyer <aurelienvoyer@...>
wrote:

I would like to calibrate duplexer with nanovna is there someone who can
help me.

--
*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*

I am afraid you really need a good spectrum analyzer to do this job.

And, even with a good piece of test equipment, it is kind of an art to do

it properly.

Get some help from someone who is experienced.

73

Glen K4KV

Spectrum analyzer plus tracking generator.

--
*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*

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

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.

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 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.