Reply With Quotehave you ever seen a 259 on a vhf freq on a spectrum analyser ? they are no longer at 50 ohms and produce a great lump of impedance at that point and are not stable as when you move the coax the impedance changes .ok
PL259/SO239 Question
The Amphenol catalogue states the maximum usable frequency is 500MHz.
Why cannot they be used at higher frequencies?
If Australia is a democracy why, then, is voting compulsory?
"What has changed between the arrival of the First Fleet and today?"
"Wearing leg irons is now not required."
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have you ever seen a 259 on a vhf freq on a spectrum analyser ? they are no longer at 50 ohms and produce a great lump of impedance at that point and are not stable as when you move the coax the impedance changes .ok
Guiseppe (10-01-19)
They are a really crap connector, and the losses at higher frequencies are just huge. They are so common cos they are cheap and easy to install, if you can avoid using them, i would. I always go N-Type for anything other than HF, but will settle for a BNC/TNC if that's the only other option.
Guiseppe (10-01-19)
They can indeed be used at higher frequencies.Originally Posted by Guiseppe
Sure, they are far from ideal, but they will work... they were never designed for higher frequencies, even though they are often called 'UHF connectors'.
Way back, when they were first introduced in the 1930's 'UHF' meant any frequency above 30MHz!
There's a huge variation of performance with them, even at lower frequencies due to materials used in their manufacture and mechanical tolerance variations. Eg: Cheap Chinese connectors are crap compared to the likes of genuine Amphenol ones meeting military spec, etc.
I agree, N-Type are best for overall performance and BNC second choice.
239/259 are OK for HF, but even then, I prefer N/BNC.
Guiseppe (10-01-19)
I was thinking 700 - 800 MHz.
Another issue is that there are different threads on them so they are not interchangeable - I bought a dummy load from USA and had to change the socket so my PL259s would screw on properly.
All BNC connectors are not the same either, apparently!
If Australia is a democracy why, then, is voting compulsory?
"What has changed between the arrival of the First Fleet and today?"
"Wearing leg irons is now not required."
The threads are meant to be all the same... again, likely poor quality connectors.
There are crap-quality connectors of all types available.
Apart from the physical attributes, BNC connectors are also available to suit different impedances.
Given the above I will have to come up with a way to "direct connect" ...
If Australia is a democracy why, then, is voting compulsory?
"What has changed between the arrival of the First Fleet and today?"
"Wearing leg irons is now not required."
redgu (10-01-19)
And BNC / SDI connectors are slightly different. The look and work similarly but one has a thicker inner connector. Put a large one into a small hole and you'll never be able to put a small one in again as the hole has been enlarged.
Guiseppe (01-02-19)
Confirms my comment in 5# above.
If Australia is a democracy why, then, is voting compulsory?
"What has changed between the arrival of the First Fleet and today?"
"Wearing leg irons is now not required."
The term SDI stands for Serial Digital Interface and does NOT refer to the connectors used on the cable used with such an interface.
Yes, the connectors used on a SDI interface are the BNC type, BUT please do not confuse the interface with the connectors used on the cable. They are NOT one-and-the-same thing.
SDI is a
impedance
sdi or bnc of this type have a characteristic impedance of 75 ohms thats why the center conductor pin is larger and wont mix with 50 ohms but the other dimensions are the same.
These are common on the back of fixed video cameras and designed for rg59 type cable not for rf 50 ohm transmission ( rg58) cable !
the main question is what do you want to use them for ? then we can give you the best advise regards don
The original question was posed because I thought I would use a SO239 in a cantenna for 1800MHz - one is in my junk box - but I canned that idea (sorry).
If Australia is a democracy why, then, is voting compulsory?
"What has changed between the arrival of the First Fleet and today?"
"Wearing leg irons is now not required."
cantenna
sorry so239 at 1800 mhz !! no sir not in the ball park you would be better with a strip connector lol go for n type but dont stop building regards don
Guiseppe (02-02-19)
Hinekadon, you appear to have missed the point completely.
BNC is a type of connector.
SDI is NOT a connector nor is it a type of connector.
Please do not CONFUSE the two.
It's particularly unhelpful to the OP, who has asked a legitimate question and to which both MTV and I have given correct (and what I consider to be authoritative) answers.
Authoritative, not because I say so, but because of what solid radio-frequency engineering principles dictate and which is succinctly stated on one of the world's leading connector manufacturer's corporate webpage.
Please see the very helpful Amphenol connector chart at .
Also the helpful 2-part article at and .
This is not hearsay but fact!
fyi tristren
some radio manufacturers use surface device interface coaxial connectors between boards others use sma or smd etc earlier the op mentioned 500/600mhz post #5 not knowing what it was to be used on i asked ???? that neither you or mtv did so we all assumed it was for general purpose but at hf type frequencys . When he said 1800mhz it changed the ball park into n type or sma or bnc types or board interconnect type there are also several other types as well I have even seen minature belling lee types and minature bnc types and mini pl259 types personally i dont care so long as he has the correct type for the job hes doing which is what he inferred in the start otherwise he wouldnt ask the question (ps amphenol are not the only connector manufacturer) cheers
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