[amsat-bb] Re: Where can I buy pre-made feedline?

[Nate Duehr]

On Dec 7, 2007, at 12:19 AM, Wayne Estes wrote:

> Nate WY0X wrote:
>
> I've seen N connectors lately that look like PL-259's and have to be
> soldered on similarly to RG-8 sized coax.  I tried one.  Pulled on the
> connector after soldering it together and it had zero strain-relief
> for the cable being pulled on, and it ripped apart.  (Well, the center
> conductor held on as long as it could).  I wouldn't use those for
> anything.
>
> Wayne W9AE replies:
>
> I've soldered dozens of "two piece" N connectors in the last 10 years.
> I've NEVER had a connector pull off, but I also haven't tried  
> pulling on
> the connector with all my strength.  The connectors have survived  
> years
> in the elements, including cables hanging vertically from my
> mast-mounted preamps, supported only by the connector.

Understand, Wayne.  I suspect that these connectors (from a mystery  
bin at HRO) weren't that great.  Normally I buy only Amphenol.

I also didn't pull with all my strength... the shield was messed up in  
very little force because the connector wasn't holding the jacket of  
the RG-8 correctly.

Once it started to let go, I just pulled harder because I knew I  
wouldn't be using it and went to go find my box with crimp N Amphenol  
connectors in it.  (In other words, if I couldn't get it right the  
first time and I usually get PL-259's right the first time... I do  
know how to solder them! -- I wasn't messing with it.  Radios are a  
lot more expensive than connectors, and I knew without a doubt that I  
could put the crimp N on correctly, having done a whole LOT of them.   
And not put the rigs at risk with connector problems.)

> I mostly use flexible 9913 or LMR400UF, and just clip a few strands of
> the center conductor to get it to fit in the connector.  Has anybody
> measured what kind of degradation that would cause at 450 MHz or 1.2  
> GHz?

I've always wondered that too.  I need to pick up some of the "UF"  
LMR400... that stuff looks nice.  Have successfully used RG-400 for  
short jumpers in the past, and it works well with the right connectors  
on it also, but it's not rated for big power.   (I don't have any big  
power amps anyway.)  At 9.6 dB/100' it's not the greatest, but for  
short flexible jumpers for things that need to move, it's fine.

Have also fiddled with small superflex in repeater installations,  
works fine for that, but annoyingly stiff for stuff at the house...  
great if you need really small but kinda "tough" stuff, it's not  
bad... putting connectors on it is a pain, but someone showed me the  
trick of using a small pipe cutter to cut the jacket and the tip,  
which works well if you're patient.

The LMR series of cable surpasses most of these older "types" pretty  
nicely though, more flexible, longer wearing... yadda yadda.  Good  
stuff.

I think if you get good at putting good quality connectors on, of any  
type -- anyone can make just about any cable work that's got good loss  
numbers for anything weak-signal.  I keep a roll of bog-standard RG-8  
around for just making up "quickie" projects or handing out to friends  
or whatever, but good quality connectors and cables just make life so  
much easier in the long run, they're well worth the money spent.

--
Nate Duehr, WY0X
nate at natetech.com