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It's not that the load wears out, it's that the jack you are attaching it to wears out. The socket for the center pin gets enlarged and deformed. It's also sliding the shield mating surface around as you tighten it.
Loads which spin the center pin and shield are really intended to be "install once" devices. Install it to specified torque, stake it, done.
Or, get yourself some connector savers (jack on one side, plug on the other)
I have a minicircuits ANNE-50L here in front of me, and I can say that the nut is definitely separate from the shield.? Spend the few extra bucks and get a real load designed for mate/demate.? If you want Amphenol, maybe a 901-10106 - I'm not sure from the data sheet or the photo, but it kind of looks like the termination is separate from the nut. (of course, it's a $13 part)

It also looks like the 132360N might be separated.? The drawing for the 132360 isn't clear. And they don't call out a gasket material on the 132360, like they do on the N You could probably invest the $3.13 to get one, look at it, and see.

Jason,
The Amphenol 132360 is rated at 1.3 VSWR (17.7dB return loss), but up to 18GHz. It looks like it has a center pin that rotates with the external nut, so it might be fine for terminating an unused port, but not so good as a repeatedly used standard. (I am basing this on the drawing, I don't have one in hand.)

--John Gord
On Sun, Dec 13, 2020 at 08:01 PM, Jason Ringas wrote:

Could the Amphenol 132360 be used for the same purpose? How would it
compare to the Mini Circuits item?

Thanks.

Can this be used as an antenna analyzer for aircraft frequencies?
Suggested firmware? Tips?

If the calibration piece you received is the same as Roger's, it means
that this NanoVNA-H4 is manufactured by us and you can use the data
provided by Kurt.

Looking through the old messages I see a post by Alan Wolke (W2AEW) where he recommends a low-cost Mini Circuits ANNE-50L+ SMA termination as a 50 ohm cal load replacement for the one provided with the NanoVNA-H4.
/g/nanovna-users/message/14199
The specifications are very good for the ANNE-50L+. The Return Loss (RL) near DC is 55 dB which is a DC resistance of 49.85 ohms compared to the one that came with my unit which measures 50.78 ohms and a RL of 42 db at low frequencies. The ANNE-50L+ RL slowly gets worse as the frequency is increased but even at 1.5 GHz (max for -H4 with factory firmware) it is 42 dB. My interests are with HF and UHF/VHF where the RL is no worse than 50 dB.
There is a belief that low frequency RL performance is a trade-off with high GHz performance. To some degree this is true as you can see in the RL vs frequency plots I attached for the mini Circuits Anne series of terminators.

From the previous thread on this subject some felt that there was no need to be concerned about RL to this degree and the supplied cal kit is satisfactory. That is true if all one is interested in is measuring/tuning antennas for VSWR and to get a rough idea of impedance. But some of us, like me, are mainly concerned with measuring components, filters, baluns, circuit S parameters etc. and we are trying to get the best performance possible from our NanoVNA. I am amazed how accurate the NanoVNA devices can be with proper attention to calibration and test fixture construction.

Roger

On Sun, Dec 13, 2020 at 01:05 PM, Dragan Milivojevic wrote:

Ask Kurt to characterize these?

On Sun, 13 Dec 2020 at 05:33, Hugen <hugen@...> wrote:

On Sun, Dec 13, 2020 at 10:19 AM, Roger Need wrote:

50.78 ohms

The load attached to the H4 has been re-matched to perform better at
higher frequencies. The 49.9 ohm load used earlier performed quite

badly

above 2GHz, but the new and improved load can get S11 below -30dB at

6GHz.

For measurements that require higher frequencies, the new load better.

For

UHF measurement, I suggest you use the load included with H4 for
calibration.

This is the test report provided by Kurt after I provided H4 OSL
accessories and 6GHz VNA to Kurt. It can be seen that the effects of OSL
accessories within 6GHz are satisfactory.
The test information provided in the attachment, OSL is the same as H4, FF
thru has been redesigned and will be provided with our future products.

Looking at the PHASE data on a single band 80m center fed dipole.
See the two attachments: one without antenna tuner, one with an antenna tunder

I've had so much fun and have learned so much about antenna parameters with this little Nano VNA device.
One of the parameters that I was not familiar with is to look at the PHASE data, say on an 80m dipole: a 130 ft long center-fed dipole with about 150 feet of low-loss RG213 50-ohm coax.

The antenna on 80m had a natural resonance around 3580 kHz (where I like to operate digi modes on NBEMS nets).
Remember at resonance, the reactance is zero (regardless of the SWR). The PHASE is zero degrees.
But that antenna had an awful SWR at the top of the band, where the phone nets play around 3990 kHz.
At 3990 kHz, the SWR was more like 4:1 and my rig was not happy.
So, how do I QSY to the top of the band with decent SWR without cutting 10 feet off my dipole?


Well, with an antenna "tuner" in the shack, I can null out the reactance of the antenna at 3990 kHz, and get an almost 1:1 SWR on the coax going to the transmitter.
My rig is "happy" at 3990 kHz with that low SWR. But the SWR is still 4:1 on my feed line.
The SWR is only reduced on the coax between the tuner and the rig.
How would a PHASE plot look for my antenna AFTER the RF passes thru my antenna tuner (T network)?

Well, a PHASE plot shows me the original resonance of the 80m dipole around 3600 kHz (without the tuner) and the SWR and RETURN LOSS graphs verify this as well. Now, post antenna tuner, matched to the TOP of the 75m band, there is a second NEW resonance at around 3900 kHz post antenna tuner. Thus, the tuner RE-REFLECTS the reflected wave at 3900 kHz back in the direction of the antenna. Something W2DU Walt Maxwell claimed was how it worked.

Fascinating stuff. The tuner (in my shack) provides a "conjugate" impedance to offset the reactance at the feed line/antenna boundary. Thus an impedance of R + jX (in my shack) combines with an impedance of R - jX in the tuner ==> resulting in an impedance of R + j0 for the radio, with R about 50 ohms. Beautiful.

And, my low-loss RG213 feed line at 4 MHz, even with a 4:1 SWR, has less than a 1 dB "loss" due to the 4:1 SWR.
A 1 dB loss is barely noticeable.
So why worry about broad-band 80m antennas (gazillion articles in QST)?
Just put a decent tuner in your shack and QSY where you want with very little attenuation in low-loss cable (on 80m).
There is also very little "loss" in the tuner itself with decent size inductors and capacitors.

So cool to see all of this concept verified on the NANO VNA PHASE plot using VNA SAVER software (Win 10).

de Barry k3eui
Phila

On Dec 9, 2020, at 9:48 PM, DiSlord <dislordlive@...> wrote:

Settings for Freq range, trace count, scale and so on, stored to calibration slot after calibration, and load after load from it.

Also you can change setting, and store to slot. Calibrate->Save>Slot N