0

Related to this question, I'm having a hard time finding a female 50-ohm load to calibrate a reference plane at the end of a male BNC feedline. However, feed-through loads are readily available.

Is there any problem using the female side of a BNC feed-through load for the "load" part of the VNA calibration?

KJ7LNW
  • 1,350
  • 6
  • 16

1 Answers1

2

At 440 MHz, a pass-thru termination is not suitable. Digikey and Mouser have many 50 ohm BNC terminators to choose from that are in stock. You may need to purchase a few different brands to find one that works reliably (you need a working VNA to suss this out).

If you're serious about doing UHF work, steer clear from BNC connectors. From a study done by a work colleague, many BNC connectors have poor performance above 100 MHz due to sloppy ground finger design. Even companies that used to make good quality BNC patch cables now sell less than stellar cables. You are better off using SMA which have more predictable performance at higher frequencies when properly tightened. N connectors without the rubber gasket is also a good choice.

qrk
  • 7,474
  • 1
  • 5
  • 20
  • Why specifically N connectors _without_ the rubber gasket? – KJ7LNW Dec 05 '22 at 00:14
  • 1
    In the GHz range, without the rubber gasket gives better performance according to my colleague who has extensively tested connector types and patch cables up to 10 GHz. – qrk Dec 05 '22 at 00:36