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SO-239/PL-259 Vs N Vs BNC, Test Results.


WRAK968
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I think this video sums it up right here,

https://www.youtube.com/watch?v=Sq3zEpYgCYo

 

This leads me to wonder though, Why do so many UHF radios come with SO-239 sockets for antenna use rather than BNC or N connectors? It even seems that newer UHF radios still use the SO-239.

Another question I have is weather or not someone should consider having the SO-239 changed out for the N type connectors? Would there be some form of improvement or has some form of compensation been made on the PC board in those radios?

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Another question I have is weather or not someone should consider having the SO-239 changed out for the N type connectors? Would there be some form of improvement or has some form of compensation been made on the PC board in those radios?

 

I keep wondering why the radio manufacturers keep using the SO-239 connector on mobile radios.  Maybe because they've always done it that way.  I absolutely HATE the SO-239 and PL-259 connectors.  They are spec'd as UHF connectors but they are not 50 ohms at UHF, probably around 45 ohms.  Mechanically, they suck too.  They also do not provide a full 360 degree termination for the cable shield.  I would not use one of these connectors above about 30MHz.  They are far more trouble than they are worth.

 

On a 440 ham repeater homebrewed from Icom UHF Part 90 mobiles, I did a little surgery on the transmit mobile and got rid of the SO-239 connector.  I replaced the SO-239 with a length of RG142U coax coming out of the mobile with an N connector on the other end. The tricky part was getting a full 360 degree shield connection to the circuit board inside and to the radio's heatsink casting.

 

The first thing I do on mobiles now is I put an N female to PL-259 adapter on the SO-239 connector on the mobile and then deal with nothing but N connectors the rest of the way.

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I keep wondering why the radio manufacturers keep using the SO-239 connector on mobile radios.  Maybe because they've always done it that way.  I absolutely HATE the SO-239 and PL-259 connectors.  They are spec'd as UHF connectors but they are not 50 ohms at UHF, probably around 45 ohms. 

Back in the old days when the PL-259 and SO-239 were invented, what we now call VHF was imagined to be UHF!

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Great video. That is why I ditched every SO-239/259... it wasn't cheap, but well worth it.

 

Motorola Mini UHF isn't that great either. Moto users don't really have much of a choice although some of those seem to be silver plated... which is better than chrome, but on several of my non-moto radios I've  resoldered the UHF with an N tri-metal.

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I have done desoldering and swapping out of surface mount components (Think 8 pin or more chips smaller than your little finger nail) so I am pretty sure I could get an N female  on my 8180 base units.

 

gman1971: By any chance did you do any before and after tests for noise/range/etc. comparison?

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Great video. That is why I ditched every SO-239/259... it wasn't cheap, but well worth it.

 

Motorola Mini UHF isn't that great either. Moto users don't really have much of a choice although some of those seem to be silver plated... which is better than chrome, but on several of my non-moto radios I've resoldered the UHF with an N tri-metal.

On the Motorola CM200/300 & PM400 radios, there is a readily available BNC antenna connector to replace the Mini UHF standard one. It simply screws in. No soldering or special tools available.

 

While this example is from the UK, they’re available from US sources as well. https://www.ebay.com/itm/MOTOROLA-BNC-ANTENNA-SOCKET-FOR-CM200-CM300-PM400-5886751Z01-FREE-SHIPPING/352424840907?epid=22021562587&hash=item520e284ecb:g:dYIAAOSw1zpbT4El

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I think its just better to have a cable go from the radio to the cavities, rather than another connector then cable, then cavities. 

 

G.

 

On the Motorola CM200/300 & PM400 radios, there is a readily available BNC antenna connector to replace the Mini UHF standard one. It simply screws in. No soldering or special tools available.

While this example is from the UK, they’re available from US sources as well. https://www.ebay.com/itm/MOTOROLA-BNC-ANTENNA-SOCKET-FOR-CM200-CM300-PM400-5886751Z01-FREE-SHIPPING/352424840907?epid=22021562587&hash=item520e284ecb:g:dYIAAOSw1zpbT4El

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I think its just better to have a cable go from the radio to the cavities, rather than another connector then cable, then cavities.

 

G.

You’re misunderstanding me. The connector I am referring to completely replaces the mini uhf. It screws in to the back of the radio. There’s no need for an adapter.

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Well, wouldn't this be considered an adapter too? an adapter to the recessed threaded connector inside the radio? I mean, the fact that there is a thread inside the radio means you could buy an RG400 cable that threads into the back of the radio and go straight to the cavity/duplexer/antenna... etc.

 

Correct?

 

G.

 

You’re misunderstanding me. The connector I am referring to completely replaces the mini uhf. It screws in to the back of the radio. There’s no need for an adapter.

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Well, wouldn't this be considered an adapter too? an adapter to the recessed threaded connector inside the radio? I mean, the fact that there is a thread inside the radio means you could buy an RG400 cable that threads into the back of the radio and go straight to the cavity/duplexer/antenna... etc.

 

Correct?

 

G.

I agree, looks like an adapter to me.  Just because it has male threads and the radio has female, doesn't mean its not an adapter 

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And there could very well be not be a shred of difference... however, I've learned (the hard way) that extra adapters, that might be seemingly innocuous (as measured), can sometimes severely cripple the entire system, due to impedance mismatch, being lose, introducing PIM due to dirty threads... etc. 

 

Loss is only a small part of the picture. I currently have a 3dBm IL on my entire feedline chain, it hasn't negatively affected the slightest bit in the range I get. In fact, I get a lot more range now with a 3dBm loss in the feedline than I ever did before with just a single LMR400 cable terminated on PL259 connectors going from radio to antenna. 

 

G.

 

 

And here I thought I saved them.
But I just read 2 articles with side x side testing and the dude running those tests said he could find literally no difference.
His meters showed loss of no more than .01dB

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