[Amps] QRO questions

[Jim Thomson]

Hi Ron

Times Microwave also makes a similar coax to RG142 called FBT-600. 
This coax was designed for high power jumpering. 

FBT-600 coax is flame retarding in nature,,, designed for running in ceiling and wall cavities. It has impressive power handling capabilities like RG142 and RG393.

I picked up a box of FBT600 jumpers at a hamfest, it came from a TV station. I chopped them up to make some 4:1 baluns.

Craig


###  FBT-600 is  VERY expensive new.. like $13.00 per foot.   It's the teflon version  of  LMR-600, but with a twist..  It doesn't use the huge  5 1/2  ga 
center conductor like LMR--600 does.  [ aprx .176"]      FBT-600 uses a smaller center conductor.. aprx .15"    I considered it's use  for a specific application
at one time.    Here's  my beef with it.    Only available connector's for it are Type N... and also LC.     LC's are  fast going out of vogue.. and a Type N  doesn't
even make it to my short list.     Times microwave  does not make a 7-16 DIN  for  FBT-600.  Dunno if anybody else does ??    7-16 Dins are plentiful.
LC's are a real pain.. and very expensive.   20 kw into 50 ohms = 1 kv rms / 1414 v peak.  7-16 DIN connector is rated for 2800 v rms  4 kv peak.
An LC connector is rated a lot more.  Center conductor on a 7-16 DIN  is a lot bigger than a LC.   The 2" square flange on a female chassis LC
makes  for huge, expensive connectors. .. like right angle LC's, etc.  

##  RG-393 is super expensive... cuz it has silver plated 13 ga   center strands.  It also has TWO  x silver plated braids.   Outer jacket
Is FEP-9   which I think contains PTFE .. or is  ptfe.      If  somebody had just made a simple teflon version of RG-213... it would have been
ample.   The loss on 393 is .98 db  vs  1.0 db   @ 30 mhz.    All that silver plating and FEP-9 outer jacket does is... add huge cost. 

later....... Jim  VE7RF