[Amps] Future of RF AMPS

[Joe Subich, W4TV]

It's probably easier to build a broadband Wilkinson divider
and combiner as used in the Quadra.

73,

    ... Joe, W4TV


On 9/11/2013 4:20 PM, dsolberg at wi.rr.com wrote:
> They don't make these combiners they buy them RF Power Systems http://www.rfpowersystems.com/index.php?option=com_content&view=article&id=80
>
> They make custom transformers and combiners, so I am sure they could make a 2 port combiner with a bigger core and larger wire to handle the extra power.
>
> Don
> K9AQ
> ---- "Joe Subich wrote:
>>
>> 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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