[TenTec] Hercules 444 amp

[Brian Carling]

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 at 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 at 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 at yahoo.com> wrote:
>>> 
>>> 
>>> Date: Sat, 9 Aug 2014 10:12:45 -0400
>>> From: Brian Carling <bcarling at cfl.rr.com>
>>> To: "k9yc at arrl.net" <k9yc at arrl.net>,   
>>> Discussion of Ten-Tec Equipment
>>>   <tentec at contesting.com>
>>> Subject: Re: [TenTec] Hercules 444 amp
>>> Message-ID: <86F80EE5-1044-42AA-9641-D8859123467B at 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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