[Amps] 6kW coax?

[Mike Tubby]

On 09/03/2012 17:37, David Shapiro wrote:
> Question for the brain trust.
>
> I am looking for a cable (possibly made in teflon or not...) with impedance
> around 70-75 Ohms that supports 6kW, this is for a final combiner for a 10kW
> transmitter.
>
> Does such a cable exist?
>
> Brand or source information?
>
> Thanks in anticipation.
>
> G4ZOW
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So, you're building a transmit combiner for an FM radio transmitter 
application?

You really need a Wilkinson combiner.  Al the power levels you're 
considering I would suggest that you make your own coax using two 
concentric copper tubes - see calculator:

http://www1.sphere.ne.jp/i-lab/ilab/tool/cx_line_e.htm

and use 7/16 DIN connectors on the IO ports.

The 100R balance load may provide a bit of a challenge ;-)  Assuming 
that you transmitters are to be well matched you might get away with 
some 100R 750W ceramic RF resistors (Florida RF):

http://www.rflabs.com/IMG/pdf/31-1054%20EDD.pdf

in series/parallel to make a 3KW 100R resistor...

Alternatively, you can find combiners for lower powers available online:

http://www.ebay.co.uk/itm/144-MHz-VHF-POWER-SPLITTER-COMBINER-HAM-RADIO-MODULE-2-X-1-5KW-3-KW-OUT-/320834979183?pt=LH_DefaultDomain_0&hash=item4ab341456f#ht_1419wt_1185 
<http://www.ebay.co.uk/itm/144-MHz-VHF-POWER-SPLITTER-COMBINER-HAM-RADIO-MODULE-2-X-1-5KW-3-KW-OUT-/320834979183?pt=LH_DefaultDomain_0&hash=item4ab341456f#ht_1419wt_1185>

this one is sold for 144MHz but its actually a 88-108MHz unit cut down 
to 144MHz - he might be able to do you an up rated version...


Mike G8TIC