I received my NanoVNA-H4 from AliExpress in just 10 days, and am happy with my purchase. However, the 50 ohm SMA calibration load goes intermittently open. The cap rotates even when the load is screwed firmly to the VNA port connector, so I think the part is defective. The calibration load from my hugen NanoVNA works properly on the H4.

What are good sources for a replacement part that have good performance to 1.5 GHz, are reasonably priced, and ship from the USA? Am I stuck buying an entire calibration kit? Thanks for any advice.

This model from Mini-Circuits is a good quality unit:
https://www.minicircuits.com/WebStore/dashboard.html?model=ANNE-50L%2B
About $7.

On Tue, 9 Jun 2020 at 18:13, Wes Plouff <ac8jf@...> wrote:

I received my NanoVNA-H4 from AliExpress in just 10 days, and am happy
with my purchase. However, the 50 ohm SMA calibration load goes
intermittently open. The cap rotates even when the load is screwed firmly
to the VNA port connector, so I think the part is defective. The
calibration load from my hugen NanoVNA works properly on the H4.

What are good sources for a replacement part that have good performance to
1.5 GHz, are reasonably priced, and ship from the USA? Am I stuck buying an
entire calibration kit? Thanks for any advice.

A Minicircuits KARN-50X+ is a pretty decent male load. Mechanically they
are good, and do not rotate as you screw them in. However, unless you
either pay lots of money, or pay someone to measure one for you, there's
never any guarantee of what it will be like. But Minicircuits have a
specification, and 99.999% of their devices meet that specification. You
may find another Minicircuits load with a better guaranteed performance to
a few GHz.

Sorry, its not the KARN, its the ANNE-50X+. Someone else mentioned another
model from Minicircuits. Pick whatever has the best guaranteed performance
over the range you want. Ignore the typical performance - that is based on
a sample of 1 from Mincircuits, which is a pretty crap way of getting a
typical set of data to me, but I was told by a Minicircuits employee that
"typical" means one random one taken from the production line.

Dr David Kirkby Ph.D C.Eng MIET
Email: drkirkby@... Web:
https://www.kirkbymicrowave.co.uk/
Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100)
Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT.





On Tue, 9 Jun 2020 at 18:23, Dr. David Kirkby <
drkirkby@...> wrote:

On Tue, 9 Jun 2020 at 18:13, Wes Plouff <ac8jf@...> wrote:

I received my NanoVNA-H4 from AliExpress in just 10 days, and am happy
with my purchase. However, the 50 ohm SMA calibration load goes
intermittently open. The cap rotates even when the load is screwed firmly
to the VNA port connector, so I think the part is defective. The
calibration load from my hugen NanoVNA works properly on the H4.

What are good sources for a replacement part that have good performance
to 1.5 GHz, are reasonably priced, and ship from the USA? Am I stuck buying
an entire calibration kit? Thanks for any advice.

A Minicircuits KARN-50X+ is a pretty decent male load. Mechanically they
are good, and do not rotate as you screw them in. However, unless you
either pay lots of money, or pay someone to measure one for you, there's
never any guarantee of what it will be like. But Minicircuits have a
specification, and 99.999% of their devices meet that specification. You
may find another Minicircuits load with a better guaranteed performance to
a few GHz.

This is what I ordered from Amazon. They are high quality and each measured 50 ohms. USA made by Amphenol that makes the best RF connectors.

Amphenol Connex 132360 (Pack of 4) RF Terminators SMA Male Resistor Cap 50 OHM https://www.amazon.com/dp/B071FF36L3/ref=cm_sw_r_cp_tau_s4-3Eb593YFGX

Gary
AA5I

On Tue, 9 Jun 2020 at 21:18, <gary.sewell@...> wrote:

This is what I ordered from Amazon. They are high quality and each
measured 50 ohms. USA made by Amphenol that makes the best RF connectors.

Amphenol Connex 132360 (Pack of 4) RF Terminators SMA Male Resistor Cap 50
OHM https://www.amazon.com/dp/B071FF36L3/ref=cm_sw_r_cp_tau_s4-3Eb593YFGX

Gary
AA5I

Actually, they are very cheap and certainly not useful for a VNA. As you
tighten them, the centre pin rotates, as the whole body rotates. A decent
load does not. You should never rotate an RF connector. So I would avoid
them at all costs. The Minicircuits ones are built properly.

Dave

On Tue, Jun 9, 2020 at 01:26 PM, Dr. David Kirkby, Kirkby Microwave Ltd wrote:

Sorry, its not the KARN, its the ANNE-50X+. Someone else mentioned another
model from Minicircuits. Pick whatever has the best guaranteed performance
over the range you want.

I wound up buying a new Mini-Circuits ANNE-50+ termination on eBay. On the NanoVNA-H and original NanoVNA, it reads a fraction of an ohm lower than the two Chinese terminators I have to compare it with. I ordered from an eBay reseller because the shipping cost for quantity 1 from Mini-Circuits or Mouser was nearly as expensive as the termination itself. This termination would be a good candidate for a group purchase.

Wes Plouff AC8JF
Royal Oak, Michigan, USA

I ordered these and got them in 2 days. They are rated at 1W to 3Ghz.. The lock down nut spins on the body.
Certainly an improvement of the once that came with the NanoVNA which failed within a month of use. I feel the price was right as well.

https://www.amazon.com/gp/product/B00BXUYDMM/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1

I have one like that from ebay and its not usable above 500MHz and had 1.7swr on 1GHz.
The typical construction for those long loads is a common metalfilm resistor inside the tube.
Mine was advertized as good for DC-2.5GHz and it was most certainly not.
I verified the performance on a HP 6GHz VNA calibrated against a HP 3.5mm calkit.

Anything recommended by Allen is more than good enough for me.
Ordered 2 from Mouser...