SMA to PL/SO adapters? #adapters


Gyula Molnar
 

Torque wrench is released with a normal wrench.
The images are related to the topic. Unfortunately I did not see a PL-SO connection.

73, Gyula HA3HZ
--
*** If you are not part of the solution, then you are the problem. ( http://ha3hz.hu/ ) ***


vaclav_sal <vaclav_sal@...>
 

Dana,
very well put. Thanks


Dana Whitlow
 

While I agree fully with the wisdom of using "connector savers" on instrument
SMA(F) connectors, I'd like to try to put things into perspective.

SMA connectors are commonly used well beyond "just a few mate/unmate cycles"
and the world has not come to an end. My key points are:

Performance degrades first at the highest frequencies. For an instrument like
the nano-VNA, you've got a long way to go before performance is notably
degraded at, say, 1.5 GHz.
If you're just doing S11 measurements, and calibrate at the free end of the
test cable each time the instrument end connection is changed or disturbed,
said calibration will go a long way towards maintaining instrument accuracy.
Sadly this is not true for the case of 2-port measurements with the nano-VNA,
which is not quite a full-blown 2-port instrument.
The SMA connectors on a nano-VNA appear to be fairly easily replaceable.
Not trivially, but if you're experienced at working with ECBs, not too difficult.
Take extreme care to avoid abusing the connectors.
a) Never apply a wrench to an SMA connector until you have clearly fully
mated the connector with thumb tightness only. If you cannot mate the
connectors with thumb tightening only, something is wrong and should
be diagnosed and corrected before continuing.
b) Always use a calibrated SMA torque wrench for that final tightening,
to avoid overtightening, to which SMAs are very damage susceptible.
And in many cases, you don't really need to tighten to full torque.
c) In support of (a), be very careful to hold the incoming cable straight
as you are thumb tightening, do avoid cross-threading or having the
center pin of the male connector slip in between the dielectric and the
outside of the pin receptacle on the female connector. This is a very
common outcome of one's trying to force the issue with a wrench upon
meeting unexpected resistance during the thumb tightening phase,
it utterly destroys the female connector, or both.
(d) Never stack up multiple adapters and/or other rigid in-line components
on an SMA connector. SMA female connectors are very susceptible
to damage from bending moments, and that long stack of items makes
for quite a lever arm. This makes it easy to destroy a female SMA
due to an accidental tug on a cable, or even gravity's downward pull.
If you must stack up components, interpose several inches of highly-
flexible cable between the female connector on the instrument and
the next item in the stack.

Other connector types (such as 'N') really are far more durable than the
SMA, but even they have their problems too. In my experience N connectors
in particular (even "precision N") often need wrench tightening in order to
obtain a solid outer conductor RF connection. Working with a VNA can teach
one a great deal about such matters.

Dana


Larry Rothman
 

Roy,
Browse the photo section of the forum and you'll find several of members that have added sma to XXX adapters where XXX can be N, BNC, PL259, TNC, etc.
Some members have created 3d-printed and other housings that hold the Nanovna with adapters as well in order to take the strain off the board mounted sma connectors. 



On Fri, 10 Jul 2020 at 5:31 PM, Roy J. Tellason, Sr.<roy@rtellason.com> wrote: On Friday 10 July 2020 03:51:46 pm Roger Need via groups.io wrote:
On Fri, Jul 10, 2020 at 12:07 PM, Roy J. Tellason, Sr. wrote:


On Friday 10 July 2020 10:51:02 am alan victor wrote:
Highly recommend putting a connector saver on your vna ports. This is a SMA
female to male adapter. Then you can bolt onto it whatever you desire. The
motivation is to prevent dirt and corruption of the connectors soldered to the
instrument pc card. Over time if you  do not use the saver the on card sma
connectors will become unreliable.

Got a source for these?
  Make sure they are not RP-SMA.  You can find them on Amazon, eBay, DigiKey and online.  Here is a link to a good quality online one In the US.

https://www.americanradiosupply.com/sma-male-to-sma-female-coaxial-adapter-connector-saver/

DigiKey has outlets in US, Canada and UK.  Picture below is a sample of what they have available.

Roger
Thanks for that info.  I will probably be getting a pair of these,  and have started a conversation with my brother,  who knows a whole bunch of the local hams who also have this device,  so hopefully we can be putting something together.  I'm familiiar with the "socket saver" concept in tube testers,  and this idea makes a whole lot of sense to me.  It's rather sad that those connectors are that fragile.  I wonder if the NanoVNA could be retrofitted with BNC connectors later on?

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin


Roy J. Tellason, Sr.
 

On Friday 10 July 2020 03:51:46 pm Roger Need via groups.io wrote:
On Fri, Jul 10, 2020 at 12:07 PM, Roy J. Tellason, Sr. wrote:


On Friday 10 July 2020 10:51:02 am alan victor wrote:
Highly recommend putting a connector saver on your vna ports. This is a SMA
female to male adapter. Then you can bolt onto it whatever you desire. The
motivation is to prevent dirt and corruption of the connectors soldered to the
instrument pc card. Over time if you do not use the saver the on card sma
connectors will become unreliable.

Got a source for these?
Make sure they are not RP-SMA. You can find them on Amazon, eBay, DigiKey and online. Here is a link to a good quality online one In the US.

https://www.americanradiosupply.com/sma-male-to-sma-female-coaxial-adapter-connector-saver/

DigiKey has outlets in US, Canada and UK. Picture below is a sample of what they have available.

Roger
Thanks for that info. I will probably be getting a pair of these, and have started a conversation with my brother, who knows a whole bunch of the local hams who also have this device, so hopefully we can be putting something together. I'm familiiar with the "socket saver" concept in tube testers, and this idea makes a whole lot of sense to me. It's rather sad that those connectors are that fragile. I wonder if the NanoVNA could be retrofitted with BNC connectors later on?

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin


Roger Need
 

On Fri, Jul 10, 2020 at 12:07 PM, Roy J. Tellason, Sr. wrote:


On Friday 10 July 2020 10:51:02 am alan victor wrote:
Highly recommend putting a connector saver on your vna ports. This is a SMA
female to male adapter. Then you can bolt onto it whatever you desire. The
motivation is to prevent dirt and corruption of the connectors soldered to the
instrument pc card. Over time if you do not use the saver the on card sma
connectors will become unreliable.

Got a source for these?
Make sure they are not RP-SMA. You can find them on Amazon, eBay, DigiKey and online. Here is a link to a good quality online one In the US.

https://www.americanradiosupply.com/sma-male-to-sma-female-coaxial-adapter-connector-saver/

DigiKey has outlets in US, Canada and UK. Picture below is a sample of what they have available.

Roger


William Heller
 

Reverse sma was used on wifi routers to discourage adding external
directional antennas which would violate the legal limits on effective
radiated power (ERP) and cause interference. Rg-6 coax is 75 ohm and is
used in the cable tv industry so the they use type f connectors. That cable
is used for l band (950-1450 mhz) for the downlink from dish and direct tv
antennas.

On Fri, Jul 10, 2020, 1:01 PM vaclav_sal via groups.io <vaclav_sal=
yahoo.com@groups.io> wrote:

Post purpose " REPLY

Went to local store and they did not have anything SMA to PL/SO.
Came home with "reversed" SMA female to RG6 female.
( I am really not sure what is reversed on the adapter - open to
suggestion / discussion / clarification )

I am also not so sure about RG6 connector name - like PLxxx.

However, I have plenty of RG6 to PL/SO adapters.

I agree - ideally less connector(s) the better , as long as the
MECHANICAL strain is not on the NanoVNA PCB.
That is my biggest concern I gathered from reading the mail here .

There probably is , or should be a 3D box with provision to securely hold
desired adapter, perhaps later project if it does not exists.
END OF POST




Roy J. Tellason, Sr.
 

On Friday 10 July 2020 10:51:02 am alan victor wrote:
Highly recommend putting a connector saver on your vna ports. This is a SMA female to male adapter. Then you can bolt onto it whatever you desire. The motivation is to prevent dirt and corruption of the connectors soldered to the instrument pc card. Over time if you do not use the saver the on card sma connectors will become unreliable.
Got a source for these?

--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin


vaclav_sal <vaclav_sal@...>
 

Post purpose " REPLY

Went to local store and they did not have anything SMA to PL/SO.
Came home with "reversed" SMA female to RG6 female.
( I am really not sure what is reversed on the adapter - open to suggestion / discussion / clarification )

I am also not so sure about RG6 connector name - like PLxxx.

However, I have plenty of RG6 to PL/SO adapters.

I agree - ideally less connector(s) the better , as long as the MECHANICAL strain is not on the NanoVNA PCB.
That is my biggest concern I gathered from reading the mail here .

There probably is , or should be a 3D box with provision to securely hold desired adapter, perhaps later project if it does not exists.
END OF POST


Dave VE3LHO
 

In either case you say you'd connect these to the vna using the short coax provided with the vna so I see no added mechanical value of the RG316 in the pigtail style adapter. They both provide adaptation from SMA (female) to SO239 with a mechanical decoupling. Neither option will have the heavy RG8/RG8X/LMR/??? cable flexing the fragile end launch PCB SMAs on the vna. Longer separating cable is not going to do much, as far as I can see.

Since you are using SO/PL connectors I guess you are probably working at HF and any electrical differences won't matter to you, as you say.

If you are trying to decide what to buy I'd suggest going with the cheapest. If you have both on hand and can't decide which to use I suggest the most convenient.

FWIW when dealing with an antenna or somehing with SO/PL connectors I personally use something more like the first option (an adapter without its own pigtail/coax). This is connected to the vna through short piece of coax with SMAs at both ends. For now I calibrate at the end of the coax wiithout adapter since I don't have a PL259 cal set. It hasn't been a problem so far but then ... we are talking about using SO239/PL259 connectors right?

I went with the adapter approach because 1) I had some on hnad and 2) I find the adpaters a little easier to work with.

On Fri, Jul 10, 2020 at 07:11 AM, vaclav_sal wrote:



Post purpose: Opinions wanted

OK,
"hold = last longer "

What type of trouble or problem are you trying to avoid?

No problem , just asking for opinion - preferably form experience
which setup falls MECHANICALLY apart SOONER during average usage ?

I am not concerned with electrical properties - software can take care of
connection losses if desired.

THE END


alan victor
 

Highly recommend putting a connector saver on your vna ports. This is a SMA female to male adapter. Then you can bolt onto it whatever you desire. The motivation is to prevent dirt and corruption of the connectors soldered to the instrument pc card. Over time if you do not use the saver the on card sma connectors will become unreliable.


vaclav_sal <vaclav_sal@...>
 

Post purpose: Opinions wanted

OK,
"hold = last longer "

What type of trouble or problem are you trying to avoid?

No problem , just asking for opinion - preferably form experience
which setup falls MECHANICALLY apart SOONER during average usage ?

I am not concerned with electrical properties - software can take care of connection losses if desired.

THE END


DougVL
 

What do you mean by

holds MECHANICALLY
?
Does your "holds" mean "grip" or "connect", or does it mean to last longer without damage? Adding the RG316 cable will make your connection more flexible and distribute bending stresses farther. That could make mechanical life longer. But extra connectors are not a good thing in any circuit.

Or do you mean "holds together" when pulling on the ends off the cable(s)?
What type of trouble or problem are you trying to avoid?


btomek@...
 

At what frequency are you going to use UHF SO239 adapters? Eg 440 MHz is definitely too high frequency, there UHF SO239 adapters can have SWR> 2, and the better ones have about 1.3. If anyone knows a really better adapter, I'm interested.


Roger Need
 

Do NOT use fixed adapters on the NanoVNA. They put too much mechanical strain on the SMA connector/PCB connection.

Roger


vaclav_sal <vaclav_sal@...>
 

SMA Female to UHF SO239 Female Adapter
or
6 Inch RG316 SMA Female to UHF SO239 Female Adapter

BOTH connected at the end of stock coax furnished with NanoVNA ,
NOT directly to hardware.

Which holds MECHANICALLY better in an average usage ?

Cheers