I have heard only ONE MFJ $2895 MOSFET amp on the air which leads me to think
the "average ham" is going for something else.
Best regards - Bry Carling
> On Aug 10, 2014, at 1:01 PM, Robert <rmcgraw@blomand.net> wrote:
>
> Many to most design parameters do change radically when converting from
> BIPOLAR to MOSFET devices.
>
> I seen to think MFJ does have their products in the reach of the average ham.
> I find typically they offer reasonable designs, reasonable quality at
> reasonable prices. Maybe it's the hams average reach that needs adjusting.
> The days of the SB-200 and SB-220 KIT prices are long gone.
>
> Good quality amps, those that are clean and don't spew garbage across the
> bands, require good design and good quality parts. Then add a high duty
> cycle and it places more demand on the designs and the parts choices.
>
> 73
> Bob K4TAX
>
> Sent from my iPhone
>
>> On Aug 9, 2014, at 5:38 PM, Brian Carling <bcarling@cfl.rr.com> wrote:
>>
>> So maybe the Hercules can be converted to use MOSFETs. Seems like it should
>> be possible.
>>
>> I also think MFJ needs some competition on MOSFET linear amplifiers to get
>> the price point within reach of the average ham.
>>
>> There is just not a good reason why so many linear amplifiers should cost
>> $3500 to $9500 when you look at the parts cost and manufacturing cost.
>>
>> [/SOAPBOX]
>>
>> Best regards - Bry Carling
>>
>>
>>
>>> On Aug 9, 2014, at 5:24 PM, Douglas <sparks06524@yahoo.com> wrote:
>>>
>>>
>>> Date: Sat, 9 Aug 2014 10:12:45 -0400
>>> From: Brian Carling <bcarling@cfl.rr.com>
>>> To: "k9yc@arrl.net" <k9yc@arrl.net>,
>>> Discussion of Ten-Tec Equipment
>>> <tentec@contesting.com>
>>> Subject: Re: [TenTec] Hercules 444 amp
>>> Message-ID: <86F80EE5-1044-42AA-9641-D8859123467B@cfl.rr.com>
>>> Content-Type: text/plain;
>>> charset=us-ascii
>>>
>>> Seems like a lot of RF power transistors are similar, so it
>>> should not be too difficult to find a substitute.
>>>
>>> Best regards - Bry Carling
>>>
>>> ------------------------------------------------------------
>>>
>>> Ah - but it is hard to find a substitute. The Ten-Tec factory can't find
>>> one.
>>>
>>> There were only a few designs of 250 to 300 watt 50V bi-polar power
>>> transistors made. The remaining ones are hard to get and have an HFE that
>>> is too high. Several such transistors have been totally discontinued.
>>> Motorola for example is out of that business. M/AComm bought some of their
>>> designs but in general bi-polar RF transistors are considered passe. RF
>>> MOSFETS are now the name of the game.
>>>
>>> Per another poster: I've not had trouble with the power supply drifting
>>> upward with temperature rise. Perhaps they solved that with compensation.
>>>
>>> 73,
>>>
>>> Doug/WA1TUT
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