[TowerTalk] PL259 Insertion Loss?

[K8RI]

On 1/16/2012 8:11 PM, Jim Brown wrote:
> On 1/16/2012 2:19 PM, Peter Voelpel wrote:
>> Some PL259 stuff is suffering from production and /or material quality more
>> then type N
> You or your friends must be buying junk connectors!  The discussion is
> about QUALITY connectors, not JUNK. REAL PL259s and SO239s from good
> manufacturers do not have the problems you describe.  The rule in the US
> is Amphenol, Amphenol, Amphenol.  You may have other good choices in EU.
No connector maker produces 100 % perfect connectors, BUT Amphenol "in 
my opinion" is the best and most consistent with good materials, 
construction, and quality control. OTOH you should still check each one 
before you install it.
I've had 2 bad Amphenols in all these years.  A connector with no 
threads and one with only half a center pin.   How they slipped through 
QC? Who knows, maybe some one was just having a bad day. OTOH by 
exceeding the connectors specifications (high voltage due to high SWR on 
160 and 75) I've blown out a few N type Amphenols.  That was not the 
connectors fault.   Sometimes we have to settle for less because they 
are all that is available or it's all our budget allows. Many hams can 
only afford the most basic equipment including antennas and connectors.  
Then it becomes our responsibility to become quality control.  You might 
have to purchase a couple extra to destroy or disassemble but for most 
hams who are *usually* a  bit more on the technological ball than your 
average technologically inclined individual and far way above the 
average person who is absolutely clueless about technology it can be an 
education.

Most of us can not afford contest stations with the latest 
state-of-the-art transceivers, amps, and antennas.  Many reuse UHF 
connectors out of necessity even though it's not really a good idea and 
many do not know that or deny it.  Typically UHF connectors only have a 
few hundred cycles in a lifetime.  I've forgotten what it is for N-type 
but I think it's only about twice that of UHF connectors.  OTOH 7-16 DIN 
are constant impedance and have a much longer lifetime. They also cost 
on the order of 10 times the typical UHF connector.


> I can show you N-connectors that are junk. Further, N-connectors on some
> cables are well known to suffer from "creep,"
That is at least as much a fault of the cable as it is the connector. 
Cables with foam insulation are not quite as solid as those 
with...well...solid dielectric.
>   whereby the center pin
> recedes back into the cable, no longer making contact with the mating
> connector. This cannot happen with the UHF family of connectors.

As I mentioned earlier UHF connectors have their own set of limitations 
one being a rather low frequency before they become a problem.
Many, but certainly not all UHF connectors will handle much higher 
voltages than N-type. I've had nearby lightning strikes where the only 
failure was a double female N-connector.  Not a mark on it, and it tests 
fine with an ohmmeter, but even at 160 and a 100 watts it's a dead 
short.   The typical failure those has been due to high voltage caused 
by high SWR at the band edges of 160 and 75.
73

Roger (K8RI)
>
> 73, Jim K9YC
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