[Collins] parallel amplifiers

[Dave Brown]

Good point, Jerry, -but easily sorted with a ferrite core double wound 
xfmr xfmr driving the load-that way you get the advantage of load 
isolation and the ability to adjust the xfmr turns ratio to suit a 
standard dummy load-eg 50 ohms etc. Scott Tilley (VE?- I forget the 
call) successfully used a pair of these combiners recently on LF to 
combine a pair of 500 watt level solid state amps. 3dB is worth it 
when you are only a dB or so below the noise on an Argo screen. But on 
HF, hardly ever.
73
 Dave, ZL3FJ

----- Original Message ----- 
From: "Gerald" <geraldj at ispwest.com>
To: <collins at mailman.qth.net>
Sent: Tuesday, July 05, 2005 8:35 AM
Subject: Re: [Collins] parallel amplifiers


> On Tue, 2005-07-05 at 09:00 +1200, Dave Brown wrote:
>> See below for a useful 'on line' design aid for wilkinson 
>> combiners.
>>  But I'm inclined to reiterate Jerry's comments- On HF, 3 dB just
>> ain't worth the effort in most cases.
>>  73 Dave, ZL3FJ
>>
>> http://my.athenet.net/~multiplx/cgi-bin/wilk.main.cgi
>
> I left out Wilkinson combiners because the load that gets the 
> mismatch
> power is floating, very inconvenient for measuring the load power 
> for
> indicating the mistuning and so tuning progress. It is somewhat
> broadband otherwise.
> -- 
> 73, Jerry, K0CQ, Technical Advisor to the CRA
> All content copyright Dr. Gerald N. Johnson, electrical engineer
>
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