[Amps] Future of RF AMPS

[Richard Solomon]

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 at 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 at 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 at contesting.com] On Behalf Of Larry
> > Sent: Wednesday, 11 September 2013 10:48 AM
> > To: amps at 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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