Re: [Amps] Future of RF AMPS

[John E Cleeve <g3jvc@jcleeve.idps.co.uk>]

Hello Don,

I have been following the interesting thread. I tried to use the 
Communications-Concept link, but there is something wrong, my brower 
does not like it. I then tried a direct route via Google and once I made 
contact with Communications-Concept, the browser, Internet Explorer 
stopped working again. Perhaps some one else might try the link.....I 
would really like to see the products on offer.
73, John G3JVC/GM3JVC.



On 11.09.2013 20:45, dsolberg@wi.rr.com wrote:
> Richard,
>
> Communication Concepts sells combiners that should work.
>
> http://www.communication-concepts.com/index.php/splitter-combiners.html
>
> Don
> K9AQ
> ---- Richard Solomon <dickw1ksz@gmail.com> wrote:
> > Rumor has it that RF Parts offered a High Power Combiner, but a 
> > search of
> > that site
> > does not show it. There are a few Combiners, but no Data to tell 
> > what they
> > do.
> >
> > Anyone have a source for a Combiner that will handle 2X 600 to 800 
> > Watts in
> > ??
> >
> > 73, Dick, W1KSZ
> >
> >
> > On Wed, Sep 11, 2013 at 9:41 AM, <dsolberg@wi.rr.com> wrote:
> >
> > > While the MOSFETs can output 1200 watts with four in 
> > parallel/push-pull,
> > > the output transformer ratio will limit the practical output to 
> > between 800
> > > and 1KW, using a 9:1 with a 50V power supply.  The 9:1 optimal 
> > output is at
> > > 800 watts.  Tokyo HyPower uses this design and they rate it for 
> > 1KW.  I can
> > > also get 1KW with my homebrew amp with (4) SD2933's, but prefer to 
> > run it
> > > closer to 800 watts to improve the IMD.
> > >
> > > If you really want the full legal limit, you would be better to 
> > have two
> > > PA modules and a combiner.  Otherwise the output transformer 
> > design is
> > > going to get real complicated.  The other option is running higher 
> > voltage,
> > > which complicates the selection of a power supply.  50 volt 
> > computer server
> > > switching power supplies are low cost and easy to obtain.
> > >
> > > I am happy with 800-1KW, but maybe someday I will try the combiner 
> > just
> > > for the fun of it.
> > >
> > > Don
> > > K9AQ
> > > ---- Leigh Turner <invertech@frontierisp.net.au> wrote:
> > > >
> > > > Larry, the RF power MOSFETS to which I refer here are the 
> > VRF2933 devices
> > > > from Microsemi. Sometimes one can find surplus and NOS ST Micro 
> > SD2933
> > > FETS
> > > > on eBay at low prices.
> > > >
> > > > 4 of these rugged 300 Watt rated devices in parallel/push-pull 
> > will
> > > yield a
> > > > saturated output power of well over 1200 Watts.  Six will 
> > comfortably
> > > yield
> > > > over the US legal limit.
> > > >
> > > > 73
> > > >
> > > > Leigh
> > > > VK5KLT
> > > >
> > > > -----Original Message-----
> > > > From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of 
> > Larry
> > > > Sent: Wednesday, 11 September 2013 10:48 AM
> > > > To: amps@contesting.com
> > > > Subject: Re: [Amps] Future of RF AMPS
> > > >
> > > > On 10-Sep-13 5:51 PM, Leigh Turner wrote: using a readily 
> > available
> > > > multiplicity (6 devices in parallel/push-pull) of cheap 50V 
> > MOSFETS
> > > sourced
> > > > from the surplus market.
> > > >
> > > >
> > > > Leigh,
> > > >
> > > > Exactly which cheap MOSFETS from what surplus market are you 
> > speaking of?
> > > >
> > > > Larry - W7IUV
> > > >
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