Info: RF Amplifiers From Thunder Amps

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David Tanks

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Apr 5, 2026, 9:36:24 PMApr 5
to valleyhams
From the Amps List reflector:


   "Tubes like the 8877, 3CX-800A7, 3-500Z are all throwaway tubes. 
Then we have the Thunder amp folks in Indonesia selling complete
1/2/4/8 kw ham amps that cover 160-6m, dirt cheap, and the price
includes world-wide shipping..and they are all packed in 3/4" thick
plywood crates."  

Here is their website:


David AD4TJ

David Gordon

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Apr 6, 2026, 6:28:09 AMApr 6
to David Tanks, valleyhams
I thought anything above 2kw was illegal for amateur use. 

David Kb4lci 


From: 'David Tanks' via Valley Hams <valle...@googlegroups.com>
Sent: Sunday, April 5, 2026 9:36:17 PM
To: valleyhams <valle...@googlegroups.com>
Subject: [Valley Hams] Info: RF Amplifiers From Thunder Amps
 
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Michael

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Apr 6, 2026, 6:32:03 AMApr 6
to David Gordon, David Tanks, valleyhams
No that’s only US regulations for stations for example Canadian Stations can use 2.25KW 

Tom Whitehurst

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Apr 6, 2026, 10:10:15 AMApr 6
to Michael, David Gordon, David Tanks, valleyhams
Actually, isn't the power output limit for most bands 1.5 kw?  But that doesn't mean you can't use an amplifier that's capable of more.  Some of the tube-type Alpha amps, for example, are capable of much more, and just loaf along at 1.5 kw.   That's a selling point for their no time limit spec amps (recall their ads showing a brick holding down a straight key).  

Your barefoot radio may be capable of higher output levels than is allowed on some bands -- for example, the 60 m band has fairly low max power limits.

If you own an 8 kw amplifier, I believe all that's required to be legal is some restraint.

Tom

Jim Clymer

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Apr 7, 2026, 9:23:37 AMApr 7
to Tom Whitehurst, Michael, David Gordon, David Tanks, valleyhams

ws6x...@gmail.com

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Apr 7, 2026, 11:53:26 AMApr 7
to Tom Whitehurst, Michael, David Gordon, David Tanks, valleyhams

Gentlepersons:

I was going to make a wisecrack about hams with 8kW amplifiers using restraint but thought better of it. I thought I had deleted my email response, but Mr. “TJ” David informed me I had sent a blank email to the group. Busted, my bad!

You can use your imagination about what my response might have been.

73,

Jim – WS6X

Jeff Rinehart

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Apr 7, 2026, 12:16:18 PMApr 7
to Tom Whitehurst, Michael, ws6x...@gmail.com, David Gordon, David Tanks, valleyhams
Well I don't have the "good sense" to use restraint like WS6X so I'll tell my Big Amplifier story.  

Somehow I had acquired a home brew amp that I wanted to sell.  I was teaching school in North Carolina at the time and of course money was not plentiful.  I advertised this home brew amp with 3 or 4 of the 3-400 tubes and would run the legal limit - plus!  A fellow came to check it out - he brought his own wattmeter and dummy load.  He found out the amp Only put out a bit less than 3000 watts on 80 meters and even less on the higher frequencies.  So . . . he didn't buy it.

I have often wondered just how much power you "Needed" to run a Carolina Kilowatt?? 

Jeff W4PJW
Jeff Rinehart   W4PJW



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Randy

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Apr 7, 2026, 12:16:21 PMApr 7
to Tom Whitehurst, Michael, David Gordon, David Tanks, valleyhams
They look kind of shady to me. You have to dig through the website a
bit to find amps for anything other than the chicken band. In fact,
they have only 2 models with frequency ranges that specifically cover
the HF amateur bands, the "hf 1K" and "hf 2K". The notation of "lpf
band" versus "lpf all band" would appear to indicate low pass
filtering at either one or at multiple bands - but that's just a
guess. Both of these models are listed as covering 160 - 6m.

$450 for "Protect Control" which is listed as a standard feature on
every HF amp. I'm not real sure what that's for outside of a feature
to manually switch a filter... and I don't know why you'd ever want to
do that. If you select a filter too high above the operating
frequency, the spectral purity requirement will not be met and if you
select a filter lower than your operating frequency, the release of
smoke will be authorized.

A quick search in the FCC database for authorized equipment does not
show these amplifiers as having been certified for use in the amateur
radio service. Search terms included:
amper
thunder
alkahfi
banyu
urip

Having an amp that's capable of 2kW+ will run cooler at the 1kW output
level. The cooler running amplifier will last longer, all other things
being equal, but that operating tradeoff is ultimately left up to the
person using the amp. Note that there's only a 3 dB difference between
1kW and 2kW which roughly translates to 1/2 of an "s-unit" at the
receiving station. I'd wager not many run their 100 watt HF radio at
the 50 watt output level either...

Given the obvious target market, I'm surprised to see that these amps
are listed as using "devices" rather than "pills". Ugh.

Randy
> To view this discussion visit https://groups.google.com/d/msgid/valleyhams/CAAh40Yhq%2BTngMwzD8xbOpF%3D7NLPq%2BG08VmhtB8oCRf42FMt9cg%40mail.gmail.com.

David Gordon

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Apr 7, 2026, 12:57:20 PMApr 7
to Randy, Tom Whitehurst, Michael, David Tanks, valleyhams
I have “acquired” a Yaesu amp that will run on 120vac, but have yet hooked it up. Maybe one day I will. Supposed to put out about 800 watts. There goes my electric bill!

David Kb4lci 

From: Randy <rand...@gmail.com>
Sent: Tuesday, April 7, 2026 12:16:07 PM
To: Tom Whitehurst <whitehu...@gmail.com>
Cc: Michael <w4ac...@gmail.com>; David Gordon <kb4...@hotmail.com>; David Tanks <ad...@yahoo.com>; valleyhams <valle...@googlegroups.com>
Subject: Re: [Valley Hams] Info: RF Amplifiers From Thunder Amps
 
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