PL259/SO239 Connecters on Scanner Antennas

[abear27]

Why are there wideband scanner antennas with SO-239 connectors on them?

The PL-259 that mates with the SO-239 is described as "does not work well above 300 MHz". What does that mean in practical terms though? I know it is challenging to make a single antenna that "works well" for a wide frequency range (25 to 1300 MHz on most of these) to begin with, but why use a connector that is already known to be poorer (instead of an "N" connector, or even a BNC) ?

Is it just a matter of widespread use of the UHF connector, or is there really not that much loss above 300 MHz?

 

[DPD1]

Mainly two reasons... They're cheap... And somehow they manged to become the default for consumer stuff.

I think CB and RadioShack is where it kind of got started... At least as far as consumers go. Most CBs had them (and they're fine for those). Then RadioShack use to sell those pre-made cheapie cables, with the 259's on there. So a lot of people started out with that and just got use to it. Now when people get cable, they often still get the UHF, just out of habit. Manufactures know this, and since those are usually less than half the cost of N, they go with those. Unfortunately, the same thing has sort of happened with the F connectors.

 

[GTR8000]

UHF connectors are junk. They have poor performance on UHF and above (somewhat ironic given their name, but at the time they were created UHF referred to what is now VHF), and they're not as water/weather resistant as N connectors are. BNC connectors are a poor choice for outdoor or permanent applications, they are meant for indoor quick-connect applications where weather resistance isn't an issue.

It's a shame to see decent antennas crippled by UHF connectors. The Radio Shack "Sputnik" 20-176 is one example. It's actually a pretty decent antenna, and for the price and small size, is one of the best values out there. But the UHF connector really cripples its 800 performance. Many discones also feature UHF connectors, but can usually be ordered with the N connector, such as the Diamond discone. D130NJ is the model number for the N version, compared with D130J for the UHF version.

 

[jackj]

PL-259/SO-239 can be junk or they can be pretty good connectors. It depends on how they are made and what materials are used to make them. Like coax, it all depends. The ones you get from Radio Shack are usually junk and only close to 50 ohms. Yes they are cheap but you get what you pay for. Quality UHF connectors cost and they are made of quality material.

Oh, by the way, N connectors are NOT any more weather proof than a PL-259.

 

[gewecke]

PL259's / SO 239's are just fine for VHF/UHF applications as long as they're weatherproofed well. I suggest amphenol connectors if possible.

n9zas

 

[N0BDW]

UHF connectors are not as bad as you may think:
UHF Connectors

 

[ramal121]

When I first got into a commercial radio gig, 800 MHz was the hot band. I worked for a Motorola MSS. What I could not figure out is how a quality radio manufacturer would think to put SO-239 antenna connectors on their radios (Mostar, Micor, Mitrek, Syntor) running at 800. But they did and I have to say they didn't seem to suffer much compared to other radios using mini uhf, N, TNC's. If it was a big problem, M would have quenched the idea early least their shiny reputation would be slightly tarnished.

As jackj mentioned, we would always toss the "mud" PL-259's that came with the antenna kits and use a better quality one.

Pl-259, probably not the best choice above VHF, but if it's all you got it will get 'er done.

 

[ridgescan]

When I upgraded my coax and patch chords at the antenna switches to lmr240, I also installed bnc connectors to the patchchords that go to the two scanners-but I did it to eliminate the need for bnc adapters. I have pl259s at the switch ends of those patchchords obviously to match the so239s there. They do just fine.

 

[W2NJS]

I thought that as techies we were expected to deal in facts, not rumors or unfounded gut feelings. This item, courtesy of N0BDW, above, tells the real story about the PL259 and S0239 connectors.

UHF Connectors