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Re: [TenTec] Hercules 444 amp

To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Subject: Re: [TenTec] Hercules 444 amp
From: Brian Carling <bcarling@cfl.rr.com>
Reply-to: Discussion of Ten-Tec Equipment <tentec@contesting.com>
Date: Sun, 10 Aug 2014 18:11:15 -0400
List-post: <tentec@contesting.com">mailto:tentec@contesting.com>
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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