[Elecraft] OT: Connectors and Murphy

[Edward R Cole]

After some apparently misguided use of connectors in my ham station, 
I am convinced the less their use the better is reliability.  Only 
high reliability connector is the barrier strip connector.

I used some multi-pin connectors for some of my control cables at the 
wall entrance plate and no longer will do that.  Cables will come 
from the barrier strip at tower top to the barrier strip on the back 
of the radio table.  Crimp connectors are used.  For absolute 
reliable connection both crimped and soldered.

I used some sub-D9, sub-d15 and sub-D25 connectors (Often referred to 
DB9, DB15 and DB25).  Nearly always the source of intermittent 
connections (I thought they would be handy for removing the control panel).

Coax connectors are more reliable but...not foolproof if there is any 
mechanical strain on the cables.  I have pulled apart any number of 
crimp-style BNC, N, sma, and TNC connectors.  The mechanical clamped 
shield style are much better for both strain and sealing.  Many an 
old-timer eme operator will tell that soldering coax direct without 
connectors is the only way to assure trouble free connections (I 
haven't quite done that - yet).

I used a bunch of bulkhead coax adapters Female-Female where all my 
coax enter from outside thru a 1/4-inch thick aluminum plate.  It is 
a good way to have them grounded to the ground rod, but...I have had 
several go bad (mostly due to moisture and corrosion).  Commercial 
installations don't do this; cable are run continuously from antenna 
to radio (if possible) or use a flexible coax jumper if feedline is 
very large (like 1-5/8 inch Heliax).  But every coax connection is a 
potential problem.

Power-Pole connectors are not going to be used by me except where I 
must (the K3).  The dc power connectors on my DEMI transverters are 
super.  They push-twist to connect and I can pickup the transverter 
with the power cord and swing it around with no disconnect (wires are 
connected with set screws and cable strain is held with threaded back 
shell clamp.

I mistakenly installed Power-Poles on my HB 120w HF amp and it does 
click in and hold fairly well but it will not stay if I pickup the 
amp and pull against the restrained power cord (the K3 with factory 
assembled PP cable disconnects by simply moving the radio).  Don't 
write me about them - I seen this topic hashed to death several times 
over 5-years I have been subscribed to Elecraft List.  I just don't 
like them - end of conversation.

I am redesigning my station control unit (panel) and it will be done 
with modular pc boards with soldered relays and (few) soldered jumper 
wires.  Only connector will be barrier strips.  I have way too much 
haywire in my current control unit and the relay board I adapted has 
relays and pc traces which will not handle over 50ma (ugh)...big 
mistake (tried to save money).  It so full of work around's and 
patches, its miracle if it works at all. Time to replace - not fix.

Murphy loves connectors!

73, Ed - KL7UW
http://www.kl7uw.com
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