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[AMPS] coax connector ratings

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Subject: [AMPS] coax connector ratings
From: (
Date: Fri, 28 Sep 2001 15:49:40 +0200
> ---------- Initial message -----------
> From    :
> To      : Steve Thompson <>, Ken Barber 
<>,   "" <>
> Cc      : 
> Date    : Fri, 28 Sep 2001 07:15:25 -0500
> Subject : Re: [AMPS] coax connector ratings
> on 9/28/01 3:45 AM, Steve Thompson at wrote:
> > The Suhner catalogue gives a graph.
> > 
> > 20MHz  5000W
> > 50MHz  3200
> > 200MHz  1600
> > 1000MHz  750
> > 10000MHz 250
> Yikes!  750 Watts into an N at 1 GHz.  That's pushing it.  In the 
> industry the typical max power that is usually talked about for N 
> is 500 Watts at 900 MHz.  Of course, the H&S figure is into a good 

A connector that's qulified up to 10-20 GHz more easily *keeps* its 
power rating when the frequency is raised.
Suhner is quite a thrustable source, at least with the cables and 
connectors they supply.

> Of course the original question was the ratings at HF.  At amateur 
> levels, there is absolutely zero problems with either the N or the 
> would believe the UHF would handle more power because of the large 
> center pin (of course the quality of UHF connectors does vary and I 
> assume a UHF with a phenolic dielectric to handle much less power 
than a UHF
> with a Teflon dielectric).

The bigger size says nothing, to the limit a smaller contact can better 
handle power at some frequency than a bigger one.
Although power handling is not the matter at HF for PL 259, the power 
handling capability decreases much more with PL259 than N going from 
2MHz to 30 or worse 50 Mhz and 144 or above.

> IMHO, there is really not much advantage to using N connectors at 
HF.  The
> performance improvement in terms of VSWR and S21 are so minimal as to 
> negligible.  N connectors are more expensive and harder to assemble.  

This is really questionable.

N connector is a qualified one with defined sizes and a standard 
mounting procedure, UHF connectors are of many types and installed as 
it happens by hams and noone else in 21st century. 
With UHF someone developed through years his own good system, others  
play UHF over cables in a very bad way.
N connectors have to be installed following a procedure over a limited 
range of cables. Knowing the procedure and avoiding to install an N 
over a wrong cable doesn't take more time and isn't more difficult at 
all, one can forget about cables with properly installed good 
connectors for years.
In a long term perspective it's cheaper than buying UHF connectors of 
fair workmanship or recycling old connectors.
Hams always spared on coax and connectors; not wise but it has been 
always like that.

> do have the advantage of being more waterproof than UHF connectors in
> outdoor environments but other than that a UHF is really a better 
> I would recommend N connectors at 2 meters and above but even at 2m, 
the UHF
> is still pretty good. 

If you really believe it, then try 1500W at 2m on a PL259/so239 and see 
what happens.

 But as the above chart shows, above 200 MHz, legal
> limit ham amps become a problem for N connectors.
> A lot of people think that because of their size that N's are 
> high power connectors.  Well, in reality the male/female interface of 
an N
> is really identical to that of a BNC connector.  Yep, center contacts 
> the same size.

Both N and BNC inner contacts are precision ones (whose it's not with 
UHF) and perfectly handle the current associated with US legal power.
On the contrary, while shield contacts of N connectors perfectly insure 
it and are not subject to moisture even if the outer ring is loose, 
with UHF the tightening of outer ring is a must and still there is 
nothing that prevents oxidization.
May be it's not bad to point out that moisture can also migrate through 
cables inside if nothing is done to avoid it.

  The difference is in the outer conductor and contacts.  If
> you doubt be try mating a male N to a female BNC.  You can do it and 
the fit
> is pretty good. 

And ?

> The geometry of the N's do make their voltage breakdown a
> bit higher than the BNC but not that much.

Voltage breakdown is anyway many times bigger than needed, another 
point that's not a point.

> If you really want high power handling, go with a 7/16 DIN.  Overkill 
at HF
> for sure though!

Surely the 7-16 is a good connector but I don't see who's unable to 
install an N connector should find easier to deal with 7-16.

Mauri I4JMY

> 73,
> Jon
> NA9D

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