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How do you identify that a UHF Connector (PL-259 & SO-239) is of a high quality and build?

Do you identify specific materials in the construction, gold plating, or other characteristics? How will I be able to determine these at a glance when browsing through a sale bin?

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    $\begingroup$ What are you looking for specifically in such a connector? Power handling? Mechanical Stability? A somewhat acceptable impedance stability over frequency? I'll be perfectly honest: PL-259 is one of the lesser designs in the history of RF connectors, and if you're after good quality, both "sale bin" and "UHF connector" aren't the most promising leads. $\endgroup$ – Marcus Müller Mar 15 '19 at 7:36
  • $\begingroup$ @MarcusMüller I'm looking for acceptable impedance over stability, and power-handling I suppose. I'm a ham-in-training, putting together my own rig at the moment. $\endgroup$ – Amin Shah Gilani Mar 15 '19 at 11:48
  • $\begingroup$ then don't go for a righ with PL-259 connectors unless you get a good device extremely cheap. PL-259 are pretty much impossible to get well for modern popular frequencies. $\endgroup$ – Marcus Müller Mar 15 '19 at 15:23
  • $\begingroup$ @MarcusMüller Well, they do work OK on HF, especially the lower frequencies in HF. And HF is still pretty popular. $\endgroup$ – Phil Frost - W8II Mar 16 '19 at 0:20
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UHF connectors are tricky, because they're not a very good connector by modern standards to begin. They have only a few redeeming qualities:

  • They are common on amateur radio equipment
  • The socket can accommodate a banana plug

Due to their non-constant impedance design, an unavoidable consequence of being designed so long ago, they don't work well above 30 MHz. They're also inherently not weather-resistant on their own, so you have to be really good about taping them outside. Personally I only use them on the back of radios that come with them: every other connector I've installed is N (anything outside), BNC (anything inside I might connect/disconnect frequently), or SMA (small things).

That said, if you still want UHF connectors and want "good" quality, I'd look for two things:

  1. A well-known brand, like Amphenol
  2. Silver plating

You may find silver plating in some sale bin, but it may be difficult to find something that's not made in China to the cheapest possible specifications. I've used these and sometimes they work well enough, but it would be prudent to test any cables you make with them by putting a dummy load on one end, an antenna analyzer on the other (or even just a transmitter and an SWR meter) and jiggling the connectors on each end to ensure the SWR stays at 1:1.

Your best bet, counterintuitively, is to look for old, surplus equipment contemporary with the design of the connector. The silver will likely be oxidized and the connector will look terrible, but don't worry, it will work anyway. If the corrosion is really bad it's easy to clean off with a silver cleaner or any of the homemade concoctions you can find on the internet.

Otherwise you'll have to order the connectors new from a reputable distributor (ie, not ebay), and they'll set you back several dollars each.

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  • $\begingroup$ huh, I didn't know about the power-handling capabilities of PL-259. Wikipedia claims "500 V peak" whereas amphenol claims 1.5 kVrms and a working voltage of 500 V; which would in all likelihood contradict the assessment that PL-259 handles even more power than N-type. $\endgroup$ – Marcus Müller Mar 16 '19 at 11:50
  • $\begingroup$ @MarcusMüller I guess you're right. Removed that claim. $\endgroup$ – Phil Frost - W8II Mar 16 '19 at 12:32
  • $\begingroup$ @PhilFrost-W8II I am surprised to see that silver-plated crimp-style N connectors are available for $5 (not eBay). Given the advantages, that's a cost-effective alternative that can be (relatively) easily assembled in the field. $\endgroup$ – Brian K1LI Mar 18 '19 at 21:59

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