Topband: New Linear amp

[Bruce]

Hi Tom,

The new Harris Flexiva 10 KW FM band (not pulse)  stereo transmitter is not 
having a heat problem with air cooling, in a reasonably small package . It 
has individual modules that can be hot switched. Will have more info when we 
install it next few weeks. It's going up on a mountain with no automobile/ 
truck road, so transporting takes time.

 I only meant that it was catching on fast in general. A French design is 
also making a 2 meter amp.

A pair of the devices, with an built in ALC, to keep the output below the 
non linear portion could could be one approach to a 1.5 KW Amp..

The Harris Salesman, Engineer, Ham, said there was already  a W2  using a 
pair, but had a small water cooled system.

73
Bruce







>> This MRFE6VP61K25H solid state device is catching on fast in amateur 
>> radio
>> circles. HF Amps next.
>>
>> http://www.m2inc.com/pdf_manuals/2M-1K2.pdf
>
>
> Here is the tough time with this, because I'm sure most people take device
> manufacturer's data at surface value. All of this stuff, to this point of
> time, is mostly vaporware.
>
> Here are the worries:
>
> 1.) While manufacturer's make wild claims about device VSWR tolerance, 
> those
> specs are really just creative marketing fantasy. A 2:1 SWR would 
> instantly
> blow the device up if peak voltage breakdown is exceeded, or over a short
> period of time if heat limits in the junction are exceeded. If you do not
> see SWR fault protection, and there are no current limits, you can bet
> devices will fail with some conditions of mismatch.
>
> Their popular U-tube video is at pulsed service with a power limited 
> supply.
> I can do the same thing with MRF150's, and actually designed a medical
> device that ran 1000 watts of peak output power on two MRF150's, without 
> SWR
> protection, on 27.120 MHz. The reason it lived is the power supply would
> barely supply 100 watts average power, and it was pulsed duty cycle with
> very low Q filters and matching.
>
> 2.) No SSB IMD spec's.
>
> 3.) All public data appears to be matched narrow-band class-C pulsed
> service.
>
> 4.) Getting heat out of a small surface transfer area at high power and 
> high
> duty cycles is a major problem.
>
> There was a good marketing presentation by the device manufacturer, but
> nothing indicates it is anything special for HF or linear service, or 
> going
> to "catch on fast".
>
> 73 Tom
>
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