[Elecraft] New KAT500 pics from the Visalia DX convention

[Edward R. Cole]

I assume all you have read this thread so not going to repeat all 
prior e-mail in my post.

First off only place you will find PL259/SO239 "UHF" connectors is on 
ham, CB and some marine radio equipment made today.  Commercial 
radios long have gone to other connectors with N-connectors being 
favored for VHF+ site located systems.  Mobiles and HT's have a 
variety of connectors from BNC, TNC, mini-UHF, RCA-phono (gawd 
awful), sma and a whole host of tiny specialty connectors used on 
wireless stuff, smart phones, etc.

In my professional life I moved most cabling to either N or BNC vs 
UHF.  This was for reliability.  BNC were normally used on RG-58 
cable jumpers and lower power stuff where measurements were frequent 
requiring cable removal.

The use of pliers to tighten connectors had gotten too many folks in 
trouble due to "super mechanic" mentality that if tight is good 
tighter is better.  Sorry these are not water or gas lines.  If you 
use a plier to tighten only rotate 1/8 turn beyond finger-tight.  I 
can see wanting to do this on antenna connections or mobile 
installations where vibration is possible.  Use of heat-shrink over 
the connector will result in longer reliability (also because it is 
now wx tight).

BTW I have measured improvement of half a dB at VHF+ by proper 
tightening of N connectors.  At HF this is probably not even noticed 
but on receivers at UHF it will make a difference.  Sma connectors 
are particularly susceptible to inadequate tightening but again 
should only be tightened with a sma wrench with 1/8 turn or by proper 
torque wrench according to the mfr's specs.  Sma do not like repeated 
removal and installation so be careful with that.  I find the threads 
in N connectors wear if removed too much and work much better the 
first or few times.

Impedance match on low noise preamps is critical so many hams are 
moving to use of either N or sma connectors over BNC.  I have not 
seen a UHF on a preamp since the 1960's.

Finally, my highest connector failure is with UHF on RG-58 size 
cable.  I really dislike the critters for that.  Crimp-style 
connectors also seem to have a higher failure if they are cables that 
are repeatedly removed (esp BNC).

So that is my two-cents on the topic.



73, Ed - KL7UW, WD2XSH/45
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