[Amps] 300 W single band mobile amp needed

[Hal W5GHZ]

Good points, Jim, but you still have to design the amp and a ready made one can be left in the 20 meter position and drive reduced.  To get the narrow phone band only operation you would have to re-design the 20 meter filter.  Why bother to go through all of that work unless you just like designing amplifiers.  Then you can start out with a cheap CB amp.  They don't have a band switch.



________________________________
 From: Jim Thomson <jim.thom at telus.net>
To: amps at contesting.com 
Sent: Monday, October 8, 2012 3:37 AM
Subject: [Amps] 300 W single band mobile amp needed
 
Date: Sun, 7 Oct 2012 08:24:02 -0700 (PDT)
From: rick darwicki <n6pe at yahoo.com>
To: AMPS <amps at contesting.com>
Subject: [Amps] 300 W single band mobile amp needed
I have a friend that runs a motorcycle mobile on 20 Meters at about 100 watts. He is looking for a schematic/info/link for a simple no tune amp of about 300W that would just cover the SSB section of 20. Any help?

Thanks


Rick, N6PE

Going from 100 watts  to 300w  = exactly  4.77 db.    That’s nothing to sneeze at....and is enough to get the job done. 
The duty cycle on SSB is such that there is no way in hell your buddy is gonna fry his brains out on 20m band.
The average power is WAY too low... and so is the freq. 

Any mono band amp has some advantages, only ONE LP filter required.    Not only that, you then also don’t have to worry
about band switching various LP filters.  You just eliminated all the switching!     You also now have the luxury of designing the
combiner so it’s  100% optimized for 20m  band.     Then you get  max eff. 

Plan B might be to use a 11m  cb amp,  and install a  20M  LP filter into it..then retweak the bias a bit.

I would not worry about IMD  on any mobile amp.  With 300w pep,and a mobile ant,  you are not gonna be 
loud enough to anywhere  for anybody to start bitching about imd. 

To supplement your battery-alternator setup,  use a .5 to 1 farad cap across the 12 vdc buss.  The car stereo
guys use these caps all the time.  They work damn good too. No more lights blinking on heavy bass notes etc.
The 11m ops also use em  for mobile applications. 

Later.......  Jim  VE7RF

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