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connector swap

paul larner #7971 hi all im thinking of changing from sma to bnc connectors on my vna,maybe mounted on an extender board hooked up to the vna with some small coax,is there any issues with doing this as regards acuracy etc,i assume using 50 ohm coax and re calibrating it should be ok?,any idea?.,cheers M3vuv.
[email protected] #7974 Why not? But i dont think they wil fit or the case wil be a lot thinker,maybe if you make a printable box around it Op zo 8 dec. 2019 09:30 schreef paul larner <quadzillatech@...>: toggle quoted message Show quoted text hi all im thinking of changing from sma to bnc connectors on my vna,maybe mounted on an extender board hooked up to the vna with some small coax,is there any issues with doing this as regards acuracy etc,i assume using 50 ohm coax and re calibrating it should be ok?,any idea?.,cheers M3vuv.
Oristo All Messages By This Member #7981 is there any issues with doing this /g/nanovna-users/wiki/BNC /g/nanovna-users/wiki/RF-Calibration%2C-considerations%2C-notes
DJ7BA All Messages By This Member #7982 Hi Paul, if N is an alternative for you: N provides much better accurate quality for higher frequencies than BNC. See pics: The (slightly hot air bent) extended PE board permits hand isolation: Often a suitable balun for avoiding body ground errors is not needed. 73, Hans DJ7BA -----Ursprüngliche Nachricht----- Von: [email protected] <[email protected]> Im Auftrag von paul larner Gesendet: Sonntag, 8. Dezember 2019 09:30 An: [email protected] Betreff: [nanovna-users] connector swap hi all im thinking of changing from sma to bnc connectors on my vna,maybe mounted on an extender board hooked up to the vna with some small coax,is there any issues with doing this as regards acuracy etc,i assume using 50 ohm coax and re calibrating it should be ok?,any idea?.,cheers M3vuv. auf 6mm PE-Brett.JPG Hei?gebogenes Brett.JPG mit70cm Dipol.JPG
paul larner #7983 seems like its dooable then,imworking on making a milled aluminium case for it so the mechanical stuff isnt an issue,was more concerned about the frequency responce,im only going to use it upto 70cms.
Dr. David Kirkby, Kirkby Microwave Ltd Member Profile All Messages By This Member #7989 On Sun, 8 Dec 2019 at 10:56, paul larner <quadzillatech@...> wrote: seems like its dooable then,imworking on making a milled aluminium case for it so the mechanical stuff isnt an issue,was more concerned about the frequency responce,im only going to use it upto 70cms. Definitely use N, not BNC. Mainly because BNC provides a less repeatable connection, and for a VNA, you should be seeking the most repeatable connection possible. Dave
Bob Albert #8007 I have been successfully using adapters from SMA to BNC.? Works great.? You calibrate with the adapter in place and readings are accurate. Replacing the connectors, while possible, makes for a lot of stress on the PC traces and can promote failure.? I wouldn't do it. Bob toggle quoted message Show quoted text On Sunday, December 8, 2019, 04:25:11 AM PST, Dr. David Kirkby, Kirkby Microwave Ltd <drkirkby@...> wrote: On Sun, 8 Dec 2019 at 10:56, paul larner <quadzillatech@...> wrote: seems like its dooable then,imworking on making a milled aluminium case for it so the mechanical stuff isnt an issue,was more concerned about the frequency responce,im only going to use it upto 70cms. Definitely use N, not BNC. Mainly because BNC provides a less repeatable connection, and for a VNA, you should be seeking the most repeatable connection possible. Dave
aparent1/kb1gmx #8011 First BNC up to 3ghz is a reliable connector, no different from TNC. Caveat; use good stuff and make sure you do not interchange 50 ohm BNC with 75 ohm BNC, really they are different! Having used BNC and TNC to 3ghz on PNAs if they make erratic connection it is time to toss the offending connectors or adapters it or at least try to clean it! They do get dirty! The other is as others have said changing the connectors stresses the case and board to make that change. Use quality adapters. One last thing SMA, use a torque wrench if your that critical. Loose is a problem and over-tighten ruins them. As a generalization If I were to go from SMA to anything it would be type N as they are fairly robust. However they are large and still need adapters. In the end if you are using decent parts (cables and adapters) the calibration takes it all in and compensates. ----------------- I do not accept private email due to forum scraping groups.io
Larry Rothman All Messages By This Member #8033 Photos? On Sun, 8 Dec 2019 at 1:49 PM, Nulluser00@...<Nulluser00@...> wrote: I mounted my NanoVNA on an Budd aluminim cast box and use male SMA to male SMA to a female SMA to male BNC to bulkhead female to female BNC. I'm building a RF project gadget box with my Elecraft XG-1 1/50uV 7.040KHz RF source Electraft NG-1 RF white noise generator and other stuff to be added as I go along. Works great.
[email protected] #8054 RE: "First BNC up to 3ghz is a reliable connector, no different from TNC. Caveat; use good stuff and make sure you do not interchange 50 ohm BNC with 75 ohm BNC, really they are different!" Yes they are different, look at the photo at The 75 ohm BNCs are much more delicate and likely to be damaged because they lack the protection of the 50 ohm BNCs However, they are physically inter-matable with no damage. The center pin OD and shield "fongers' ID are identical, so can be inter-mated wtih no damage. The impedance bump is probably not too bad below 5MHZ because before ATSC, when NTSC was used, virtually every BNC connector installed on 75 ohm coax and used in NTSC video equipment was the 50 ohm variety. .
Shirley Dulcey KE1L All Messages By This Member #8068 And check the connectors, not the markings on the cable. I have seen 75 ohm coax jumpers with 50 ohm BNC connectors on the ends. Such cables are not recommended if you are using a resonant antenna, but will be just fine if you are using a non-resonant antenna with an antenna tuner. toggle quoted message Show quoted text On Mon, Dec 9, 2019 at 8:36 AM <Nulluser00@...> wrote: RE: "First BNC up to 3ghz is a reliable connector, no different from TNC. Caveat; use good stuff and make sure you do not interchange 50 ohm BNC with 75 ohm BNC, really they are different!" Yes they are different, look at the photo at The 75 ohm BNCs are much more delicate and likely to be damaged because they lack the protection of the 50 ohm BNCs However, they are physically inter-matable with no damage. The center pin OD and shield "fongers' ID are identical, so can be inter-mated wtih no damage. The impedance bump is probably not too bad below 5MHZ because before ATSC, when NTSC was used, virtually every BNC connector installed on 75 ohm coax and used in NTSC video equipment was the 50 ohm variety. .
Bob Albert #8083 To do the job the best way I would connect a short cable to the SMA and terminate it in whatever series I want, say BNC or N or UHF.? To avoid further stress it might be wise to put the cable end with BNC etc on a small bulkhead that is solidly mounted.? That should alleviate all stress on the vna and would last a long time. As was said, do calibration after all is in place. Bob toggle quoted message Show quoted text On Sunday, December 8, 2019, 10:49:49 AM PST, <nulluser00@...> wrote: I mounted my NanoVNA on an Budd aluminim cast box and use male SMA to male SMA to a female SMA to male BNC to bulkhead female to female BNC. I'm building a RF project gadget box with my Elecraft XG-1 1/50uV 7.040KHz RF source Electraft NG-1 RF white noise generator and other stuff to be added as I go along. Works great.

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