[Elecraft] Amp power per $$ spreadsheet download

[Bob Naumann]

Just to clarify a couple of things: the Acom amplifiers *do not* have
antenna tuners built-in.  

They merely use a traditional tuned final design that has the ability to
match into a moderate range of impedances.  This can be up to a 3:1 SWR in
certain limited circumstances (less on 160m).

If you have resonant antennas, you'll be just fine - even at the extremes of
75/80m in many cases.  If you have a very narrow band antenna, not so much.

The Acoms have no more of an "antenna tuner" than did an SB-220 or a 30L1
for example.

Also, aside from the new Solid State Acom 600S (with a switching power
supply), all of the Acom amplifiers use traditional linear power supplies
with multiple taps on the primary which allows using them on 120 to 240v,
single phase.

Needless to say, using them on 240v is best for numerous reasons.

73,

Bob W5OV


-----Original Message-----
From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jim
Brown
Sent: Sunday, April 26, 2015 5:35 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Amp power per $$ spreadsheet download

On Sat,4/25/2015 7:35 PM, Phil Wheeler wrote:
> Good job, Nick.  I didn't realize my AL-811H was so cost effective. 
> Sure is a royal PITA to use, though. I'll give it away to someone 
> local who will use it -- no way I will deal with shipping the beast. 

I modified the spreadsheet a bit and re-sorted it. First, since we here 
in the US are permitted only 1,500W, I set max power for those amps with 
higher power ratings to that value. Second, just as Nick has included 
his used Alpha 99, I added my used Ten Tec Titan 425s.

k9yc.com/PwrAmpdB.png

There are many features and properties of power amps that go far beyond 
pure dB per dollar.  some examples:

The ACOM 1010 is a reasonably compact competitor to the KPA500, but it 
doesn't cover 6M. I bought one used from K6SRZ (to have another amp for 
CQP), who bought a KPA500 just to get 6M. Also, my occupied bandwidth 
tests show that the KPA500 is a bit cleaner than that ACOM 1010. And the 
1010 is a single-voltage amp. It must be rewired to change it. The 
KPA500 can be switched by removing, rotating, and reinserting the fuse 
block built into the power plug.

The ACOM 1000 does cover 6M. Both it and the 1010 have manual antenna 
tuners built in. Some of these amplifiers have built-in tuners, some of 
those tuners are automatic or have memories. Some of these amps are much 
better built than others. My Ten Tec Titans use high quality vacuum 
relays with logic to prevent hot-switching, as do the Alphas. The 
Ameritron amps I've seen use much cheaper open-frame relays, so their 
switching is much slower.

My Titans are quite clean -- P3 measurements of both the KPA500 and the 
Titan look exactly like the K3 at the drive level required for rated 
power. But the Titans, like the lower cost ACOMs, are "manual everything.

73, Jim K9YC
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