[Amps] Mobile Amps

[Jim Thomson]

Date: Fri, 14 Apr 2017 12:49:50 -0300
From: "Mike Smith VE9AA" <ve9aa at nbnet.nb.ca>
To: <amps at contesting.com>
Subject: [Amps] Mobile Amps ?

I am thinking of upgrading my mobile station from 100w to something more.
500-600w minimum.

At one time there seemed to be more choices available to the mobile ham but
now about the only choice seems to be the Ameritron ALS-500. At $1350 CDN
+ 15% tax and then shipping, (making it about $1600 CDN) it's not cheap for a 
350-400w (CW) amp. I don't mind paying for quality, but what scares me more 
about this amp are some of the less than glowing reviews.

 

In my limited research I've found:

(RM Italy seems like lower power and some are illegal in NA)

(SGC no longer making the power cube I don't think)

(THP out of business)

 

What else is out there? 
Thanks
Mike VE9AA..VE9AA/m

##  SGC power cube would be good..if bought used, but dunno abt getting parts
for it..perhaps unobtainium.     The  ALS-500   will end up being sent back to radio 
world a half doz times getting repaired.  Pita.   VE6RF bought a AL-600, only to 
blow it up in a few mins,  replaced, and  another repeat blow up.   Ameritron had not 
soldered the final transistors in correctly, leaving  an air gap between  transistors and
mating heat sink...so they had no heat sink = kaboom.  3rd one finally worked, but 
what a pita, with shipping costs.   Its almost better to buy 2 of em, and send back 
which ever one doesnt work...and get a refund on it.  

##  The RM italy amps here in town seem to work pretty good.  IMD on ssb
in a mobile application is a non issue, since you dont have much of a signal
to begin with.   Didnt know abt SS amps and key clicks  +  high swr.  Assuming
a screw driver ant used, swr is a moot point.   CW has a lot higher duty cycle than ssb,
esp when sending dashes...with a 4 to 1  weighting.  

##  500 watts out means sucking 1kw  from the battery..which is a helluva lot.   1 kw
divided by 14 vdc =  71 Amps.   Are you sure you want to do this ?   Think you would
want at least a 135 to 160A  alternator...and maybe a 2nd battery.   And maybe one
of those   4-10 farad caps across the amps 14 vdc input terminals.    And big gauge
wire  to minimize V drops, like min 6 gauge, or perhaps paralleled 8 gauge. 

## Assuming you are stationary while sending CW,  you would probably want to leave
the eng running.   If you are using 2 batteries, you may want to diode isolate em, so
you only use the amp one  of the batteries, so you can charge both of em up with the
alternator, but only have the amp running on one battery.   Then  you can never kill the
2nd  battery.  With 2 semi dead batteries, you might not be able to start the eng. 

##  I would not use a  deep discharge battery.  Oem start batteries are designed for
high start current. 

Jim   VE7RF