Date   

Re: QCX mini: RF output BNC or SMA #poll-notice

George Korper
 

OK. I am thinking the longer BNC with the threads could be substituted with one that is shorter
and needs no nut and lock washer. Democracy is all about arriving at the best solutions...hee hee. 
It may be fractionally cheaper too. 

OH let Hans decide, the topic is exhausted. 

On Thu, Aug 6, 2020 at 12:00 PM ajparent1/KB1GMX <kb1gmx@...> wrote:
Shorter BNC is the same.  How reliable they are for its connection to
the board is unknown as all the systems used a variant that locked
to the chassis. for mechanical support.

I do not see the problem being lifetime in use.  More like user friendliness.
Small connectors are harder to handle both in use (that 5/16th nut on SMA)
and also making cables. 

For every socket connector wear out on gear I've had cables fail in use many
many times over and that applies to C, N, BNC, TNC, PL259, SMA, SMB. 
Some connectors however provide better support for the cable and generally
SMA [and SMB] do not.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Re: QCX mini: RF output BNC or SMA #poll-notice

Skip Davis
 

SMA connectors are nice and cute on small rigs but BNC are far easier to use with fat fingers. Also how many have actually ever made up SMA cables and adapter cables? It’s pretty tough and much harder than BNC. Most people will hang a SMA/BNC adapter off that SMA which defeats the purpose of the choice of the smaller connector.
Just my thoughts on this YMMV.

Skip NC9O


Re: 500 times for the SMA

George Korper
 

Good low profile solution, and they work fine for me. Used on SotaBeam tuners. 


On Thu, Aug 6, 2020 at 12:02 PM <g3vgr@...> wrote:
I never understood why hf qrp rigs have BNC sockets. They're totally unnecessary at HF, difficult to use with RG174 and breakages in the field are impossible to easily repair.
For portable operation, I've always used phono plugs on coax feeder and a phono/BNC adapter on the BNC socket. Much easier
73, Dave G3VGR


Re: Who needs feet for their builds?

Jim Netwal
 

Mark,

Can you attach a picture with them installed please?

73, Jim W9UUM


Re: 500 times for the SMA

g3vgr@...
 

I never understood why hf qrp rigs have BNC sockets. They're totally unnecessary at HF, difficult to use with RG174 and breakages in the field are impossible to easily repair.
For portable operation, I've always used phono plugs on coax feeder and a phono/BNC adapter on the BNC socket. Much easier
73, Dave G3VGR


Re: QCX mini: RF output BNC or SMA #poll-notice

ajparent1/KB1GMX
 

Shorter BNC is the same.  How reliable they are for its connection to
the board is unknown as all the systems used a variant that locked
to the chassis. for mechanical support.

I do not see the problem being lifetime in use.  More like user friendliness.
Small connectors are harder to handle both in use (that 5/16th nut on SMA)
and also making cables. 

For every socket connector wear out on gear I've had cables fail in use many
many times over and that applies to C, N, BNC, TNC, PL259, SMA, SMB. 
Some connectors however provide better support for the cable and generally
SMA [and SMB] do not.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Re: QCX mini: RF output BNC or SMA #poll-notice

Giuseppe Marullo
 

Maybe something like these are a little better/sturdier:

https://www.knjn.com/ShopFlashyWidyAccessories.html (don't know Jean source tough)


Definitely SMA are not the best if you need many connect/disconnect cycles. They are not even nice to handle compared to BNC, let's admit it, size ok but why suffer?

They change characteristics based on the torque applied (yes, both ways, more or less torque do both affect the measure), I have a MiniVNA Pro and it is nasty when performing calibration, you just need the exact range of torque else the graph will be funny. Not nice.

I ended up using a SMA saver(m/f) on each connector to limit the wear (SMAs are a PITA to substitute on the MiniVNA),sadly it won't do much on the torque issue.

Giuseppe Marullo
IW2JWW - JN45RQ

On 8/6/2020 4:38 PM, Shirley Dulcey KE1L wrote:
BNC connectors without the plastic housing exist. I have a mini oscilloscope, a DSO138, that has one.

Here are links to examples:
https://www.digikey.com/product-detail/en/molex/0731000105/WM5524-ND/1465146
https://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/5414373-1/A32274-ND/811172

On Thu, Aug 6, 2020 at 10:26 AM Kees T <windy10605@... <mailto:windy10605@...>> wrote:

I would say prefer board mount BNC .....but find one which does
not have the plastic housing (I believe they have those). If you
are really an industrious builder with all 5 fingers on each hand,
cut the plastic off and solder the two locator pins to the bare
BNC barrel for mechanical rigidity. they are not connected to
anything anyway on the ones I have dissected. There is also the
"locate off board" option ....not preferred.

Having the two footprints on top of each other (BNC/SMA) would
allow the option.

73 Kees K5BCQ


Re: QCX mini: RF output BNC or SMA #poll-notice

George Korper
 

Agree with Allison. The extra length of the plastic gets snaggy when putting a radio in a bag. 
If you look at a QCX the long BNC is ridiculous. So I ask Allison if the shorter BNC is reliable. 

On Thu, Aug 6, 2020 at 11:42 AM ajparent1/KB1GMX <kb1gmx@...> wrote:
SMA for size. 
BNC for durability and less fiddly when up on a hill with cold hands.

Note some of the PCB edge mount BNC may provide a lower profile.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Re: 500 times for the SMA

George Korper
 

Well actually, I only object to the length of the current BNC.
I was trying to match the "MountainTopper" and a short BNC is used on that I think. 
So I would like to see Han's comment on
reducing the length. The size really needs to include that. 

On Thu, Aug 6, 2020 at 11:40 AM ajparent1/KB1GMX <kb1gmx@...> wrote:
Worn out dozens over the years.  I'd add 500 is optimistic.
Failure mode is center socket looses flex and fails.
Second most common the center pin of cable breaks loose
from the internal wire.

Best are the stainless steel steel types, the gold ones are eye candy
and generally fail faster though are easier to solder.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Re: QCX mini: RF output BNC or SMA #poll-notice

ajparent1/KB1GMX
 

SMA for size. 
BNC for durability and less fiddly when up on a hill with cold hands.

Note some of the PCB edge mount BNC may provide a lower profile.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


Re: 500 times for the SMA

ajparent1/KB1GMX
 

Worn out dozens over the years.  I'd add 500 is optimistic.
Failure mode is center socket looses flex and fails.
Second most common the center pin of cable breaks loose
from the internal wire.

Best are the stainless steel steel types, the gold ones are eye candy
and generally fail faster though are easier to solder.

Allison
-------------------------------
Please reply on list so we can share.
No private email, it goes to a bit bucket due address harvesting


500 times for the SMA

George Korper
 

We should live so long! 


Re: QCX mini: RF output BNC or SMA #poll-notice

jjpurdum
 

Regardless of the connector used, I would likely not mount it on the PCB even if the board provides for it. Off-board mounting, to me, gives me more flexibility in the case I might use. My problem is that I tend to "snag" things, often breaking them off. I originally voted for the SMA for that reason, but when I started reading about the SMA problems that some have, I changed my vote. I can put the connector off board, too, and will factor that into my nexts case. For my next QCX case, I am 3D printing a case with an "recessed box" in it. The box will be open by removing a two-screw panel that covers the box. On the front will be the (alas, discontinued) mini paddle that QRPGuys used to sell:

Inline image
I plan to mold brass nuts into the case front and will use brass thumb screws to attach the dit paddles to the circuit inside. A molded center contact point is the ground. When I'm done operating, I'll detach the paddle and store it with the screws in the "recessed box". That way, no heavy set of paddles to drag along and I can't snap them off when packing it for travel. All this is easier for me if the connectors are "off board".

Jack, W8TEE

On Thursday, August 6, 2020, 10:59:09 AM EDT, Al Holt <grovekid2@...> wrote:


I admit I voted for SMA, mainly on the basis of my experience with those threaded plastic BNC connectors, UGH!
I'm more in favor of a bulkhead mounted connector with a jumper to the board. If the the mini design is going to hold up out in the field, it's better not to depend on a board mounted connector, BNC or SMA.

With SMA connectors able to work into the GHz range, it's no wonder a manufacturer would want to limit the number of reconnections to stay in spec.

--Al
WD4AH


Re: QCX+ 30 done! Low power.

Ronald Taylor
 

James, if you are getting that much power out, then everything else is probably good, so OK to play with the lowpass filter. 

Ron


Re: QCX mini: RF output BNC or SMA #poll-notice

Bill Cromwell
 

Hi,

I have a nanoVNA with SMA fittings. The early deterioration most likely affects their performance in the microwaves. I use mine at HF and may use it some day a time or two on two meters but probably not. I take reasonable care to not wear or damage the connectors soldered into the unit and I don't expect a lot of trouble from them.

For my radios I like the BNC and UHF (PL-259) connectors. I have used RCA, SMC, C, and N connectors.

bark less - wag more

On 8/6/20 10:59 AM, Al Holt wrote:
I admit I voted for SMA, mainly on the basis of my experience with those threaded plastic BNC connectors, UGH!
I'm more in favor of a bulkhead mounted connector with a jumper to the board. If the the mini design is going to hold up out in the field, it's better not to depend on a board mounted connector, BNC or SMA.
With SMA connectors able to work into the GHz range, it's no wonder a manufacturer would want to limit the number of reconnections to stay in spec.
--Al
WD4AH


Re: QCX mini: RF output BNC or SMA #poll-notice

Shirley Dulcey KE1L
 

Please, no. Those give me nightmares. Too many cases of them either not staying in or refusing to come out.


On Thu, Aug 6, 2020 at 11:11 AM Phil/K3UT (ex W3HZZ) <pgraitcer@...> wrote:
What about RCA connectors?


Re: QCX mini: RF output BNC or SMA #poll-notice

Phil/K3UT (ex W3HZZ)
 

What about RCA connectors?


Re: help !

Ronald Taylor
 

Jay, did you check voltages on IC5, 6  and 7 yet? Are you seeing the nominal 2.5 volts at pins 1,2,3,5,6 & 7 of all three of those? 

Ron

On Thu, Aug 6, 2020 at 5:40 AM ny2ny <jayb1943@...> wrote:
Hi john tnx for response. Yes went 10+ turns in each direction on each pot while watching the bar graph. No combination of settings has any effect on the bar graph. Just stays at 2/3 or so. Any other ideas appreciated. 73 JAY, NY2NY 


Re: QCX mini: RF output BNC or SMA #poll-notice

Dave VE3LHO
 

Supporting both SMA and BNC footprints makes a lot of sense to me.

Use right angle, PCB mount connectors. Not the edge mount SMA's like those used on the nano. I'd expect that having the connectors break off the PCB would be a bigger issue then having the connector wearout from use when we're talking about people using this in a portable environment. In both SMA and BNC you can get right angle connectors which have mounting nuts that allow fairly rigid mounting to a case.


On Thu, Aug 6, 2020 at 06:09 AM, Scott McDonald wrote:
Hans, any chance the connector location on the board could be etched to support both?  A bnc -sized hole should work for SMA, other than for weather sealing perhaps.
 
Keep up the good work :)
 
Thanks, Scott ka9p


-----Original Message-----
From: Hans Summers <hans.summers@...>
To: QRPLabs@groups.io
Sent: Thu, Aug 6, 2020 7:44 am
Subject: [QRPLabs] QCX mini: RF output BNC or SMA #poll-notice

A new poll has been created:
On the proposed QCX-mini, do you prefer a BNC connector like on QCX, or an SMA connector? 
1. BNC
2. SMA
Do not reply to this message to vote in the poll. You can vote in polls only through the group's website.


Re: QCX mini: RF output BNC or SMA #poll-notice

Al Holt
 

I admit I voted for SMA, mainly on the basis of my experience with those threaded plastic BNC connectors, UGH!
I'm more in favor of a bulkhead mounted connector with a jumper to the board. If the the mini design is going to hold up out in the field, it's better not to depend on a board mounted connector, BNC or SMA.

With SMA connectors able to work into the GHz range, it's no wonder a manufacturer would want to limit the number of reconnections to stay in spec.

--Al
WD4AH