[Amps] Future of RF AMPS

[Joe Subich, W4TV]

None of the Communications Concepts two amplifier combiners are rated
at 2 KW.  They show 4 amplifier (4 port) devices for 2 and 5 KW but
the only high power 2 port combiner is rated for only 1 KW.

While it might be possible to modify one of the 4 port sets for 2 port
operation, there are no application notes on the site concerning the
splitter/combiner products.

73,

    ... Joe, W4TV


On 9/11/2013 3:45 PM, dsolberg at 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 at 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 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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