[1000mp] (no subject)

[D. J.]

The IMD products from a amplifier are not table flat.  Check out the  
IMD curve for a BLF147 and you'll find it bottomed out at about 90  
watts at -45 db down, and -40 db down between 45 and 120 watts for a  
single BLF147.  So you could be running 240 watts output with a pair  
and still be below -40 db IMD. Also keeping in mind that turning your  
power way down also brings up the IMD, check out the curve, at 80  
watts out for a pair, the IMD goes up about -35 db, but it appears  
that if you want minimum IMD from a MKV you'd be wanting to turn down  
the power to about 160 watts out, that would give you typically a  
minimum of -45 db third order IMD as opposed to 200 @ -42, -3 db  
worse.  In any case the BLF-147 IMD performance is quite a bit better  
than the 2SC2879 which is what's in the old FT1000MP.

The only worry I'd have then is the heat sink and cooling air  
adequate and is the power supply up to the task.  For the .79 db gain  
you'd see by going from 200 to 240 just ain't worth it in my book.

Dale j.













On 07, Oct 2005, at 10:36, Scott Manthe wrote:

> Every rig is capable of more than it's rated output. Unfotunately,  
> getting there usually requires an increase in IMD and hence more  
> splatter on the bands and interference for your ham neighbors.
>
> The autotuner also will not like too much more output, because it  
> can barely handle 200 watts.
>
> So yes, the Mark V is capable of more than 200 watts, but why? 225  
> or 250 watts is not going to be perceptable on the other end, it's  
> going to make your signal dirtier and it's going to stress the  
> tuner. And if you can't drive an amp to full output with 200 watts,  
> it needs to be redesigned.
>
> 73,
> Scott, N9AA
>
>
> Bob Martin wrote:
>
>
>> I was told that the Mark 5 was capable of more output than 200  
>> watts without
>> causing damage to the finals.  Is this true, and if so, what internal
>> changes are necessary?
>>
>>
>> Every Day Hamday
>>
>>
>>
>>
>>
>>
>
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