[Yaesu] Mark V Field Power Output Mod

[Jan Erik Holm]

Thank´s

this goes hand in hand with what measurements show!

73 Jim SM2EKM
----------------------
Joe Subich, K4IK wrote:

> It's hardly a guess since every advertisement, the brochure on 
> Yaesu's US web site and the brochure/specifications on Yaesu's 
> far east web site all say 100 Watts.  The only place 200 Watts 
> is even mentioned is Yaesu.co.uk.  Even at Yaesu.co.uk, the 
> narrative (page 1) of the Field information starts: 
> 
>  > Conservative 100W Low Distortion Final Amplifier Design
>  >
>  > The Field utilizes a pair of high-dissipation 2SC2879 
>  > bipolar transistors in a push-pull design, driven by 
>  > push-pull 2SC3133s, yielding a low-distortion 100- Watt 
>  > transmitter compatible with the Class-A operation 
>  > capability pioneered on the MARK-V FT-1000MP. These 
>  > transistors are run well below their rated output, and 
>  > are utilized in conjunction with pure local oscillator 
>  > signals and time-proven low-pass filter designs, to 
>  > provide you with the cleanest signal on the band! During 
>  > Class-A operation, SSB power output becomes 25 Watts, and 
>  > transmitter intermodulation products will be significantly 
>  > better than Class AB.
>   
> If Yaesu had respecified the Field for 200 Watts, even if 
> unofficially, you would see every vendor trumpeting that 
> information.  Typo is almost a certainty. 
> 
> In fact, here is the Toshiba 2SC2897 spec sheet web: 
> 
>    http://www.qsl.net/df7tv/datasheets/2SC2879.pdf
> 
> While the transistor is rated to 100 Watts, it shows substantial 
> non-linearity (> 1 dB gain compression) above 80 watts.  Best 
> (lowest) IMD occurs in the vicinity of 60 Watts output (120 Watts 
> for a pair).  At 100 watts the IMD is worse than -24 dB.  
> 
> The point is ... 200 Watts (or even 150 Watts) from a Field 
> is completely irresponsible.  With only a $310 difference in 
> the retail price, to risk blowing the final amplifier transistors 
> or increased IMD with a Field is the hallmark of the immature 
> persons who illegally "hotrod" CB radios.  
> 
> 73, 
> 
>    ... Joe, K4IK 
>  
> 
> 
> 
> 
>>-----Original Message-----
>>From: 1000mp-bounces at mailman.qth.net
>>[mailto:1000mp-bounces at mailman.qth.net]On Behalf Of Joe Subich, K4IK 
>>Sent: Friday, August 06, 2004 10:42 AM
>>To: 'All about Yaesu 1000mp'
>>Subject: RE: [1000mp] Re: Mark V Field Power Output Mod
>>
>>
>>
>>If you would bother to look at the information on the FT-1000MP/MKV 
>>on the same site, you will find identical data for the MKV.  Someone 
>>has simply failed to update the specifications when doing a cut and 
>>paste. 
>>
>>Look at the specification sheet here: 
>>
>> 
> 
> http://www.yaesu.com/downloadFile.cfm?FileID=675&FileCatID=156&FileName=
> MARK%20V%20Field%5FBrochure.pdf&FileContentType=application%2Fpdf  
> 
> You will see:  "Adjustable up to 100 Watts
>                 (25 Watts AM carrier)." 
> 
> 73, 
> 
>    ... Joe, K4IK 
>  
> 
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