Re: Balun Questions.

[Elecraft mailing list]

On 09/02/16 17:15, [hidden email] wrote:

<Snipped>
> > If you lose, it is never good when the center conductor shorts to the
> >shield at Kilowatt power levels.  Use loops large enough to stay within
> >the bending radius of your coax.  Now if this is QRP, you could
> >probably get away with it.

There are coax cables out there that can run safely too hot to handle.  
Teflon dielectric and FEP outer cover.

It's used in multi kW industrial amps and power combiners, wrapped
around many ferrite cores, often with fan cooling, for the ferrite, not
the cable!

Commercial (Broadcast) baluns too are sometimes immersed in oil, much
like power transformers, for cooling.  That's at the 10's of kW power
level.   But the coax is the high temperature stuff again.

Use suitable cable for the job, not cheap polyethylene stuff.

Dave G0WBX.

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

[NK7Z]

Hi Dave G0WBX,
I used to deal with some of those prior to retirement, worked in a
broadcast shop for about 40 years...  What a difference digital has
made to TV broadcast! :)
--
73's, and thanks,
Dave

For software/hardware reviews see:
http://www.nk7z.net

For MixW support see:
https://groups.yahoo.com/neo/groups/mixw/info

For SSTV help see:
http://groups.yahoo.com/neo/groups/MM-SSTV/info



On Tue, 2016-02-09 at 17:54 +0000, Dave B via Elecraft wrote:

> On 09/02/16 17:15, [hidden email] wrote:
>
> <Snipped>
> > > If you lose, it is never good when the center conductor shorts to
> > > the
> > > shield at Kilowatt power levels.  Use loops large enough to stay
> > > within
> > > the bending radius of your coax.  Now if this is QRP, you could
> > > probably get away with it.
>
> There are coax cables out there that can run safely too hot to
> handle.   
> Teflon dielectric and FEP outer cover.
>
> It's used in multi kW industrial amps and power combiners, wrapped 
> around many ferrite cores, often with fan cooling, for the ferrite,
> not 
> the cable!
>
> Commercial (Broadcast) baluns too are sometimes immersed in oil,
> much 
> like power transformers, for cooling.  That's at the 10's of kW
> power 
> level.   But the coax is the high temperature stuff again.
>
> Use suitable cable for the job, not cheap polyethylene stuff.
>
> Dave G0WBX.
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]